MT&M lab manual

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LAB REFERENCE MANUAL

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Geethanjali College of Engineering and Technology Department of Mechanical Engineering 1 Geethanjali College of Engineering and Technology Cheeryal V Keesara M R.R. Dist. 501 301 Machine tools metrology Subject Code: 55604 LABORATORY MANUAL III Year 1 st Semester 2015-2016 Department of Mechanical Engineering

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Geethanjali College of Engineering and Technology Department of Mechanical Engineering 2 MACHINE TOOLS METROLOGYSubject Code: 55604 Laboratory Schedule Important reminders: 1. 1 ST TURN: FORMATION OF GROUPS. 2. HANDLE THE EQUIPMENT WITH CARE. 3. SET THE CUTTING TOOL POSITION PROPERLY. 4. CHECK THE DIMENSIONS AT REGULAR INTERVALS WHILE MACHINING. 5. TAKING THE READINGS CAREFULLY. 6. TAKE INITIAL ON THE MEASURED DATA/OBSERVATIONS. CONTENTS Machine tools S. No. Name of the Experiment Page No. From To 1 Introduction of general purpose machines-lathes drilling milling shaping slotting machines 2 Facing and Step Turning Operation 3 Taper Turning Operation 4 Right Hand Screw Thread Cutting And Knurling Operation

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Geethanjali College of Engineering and Technology Department of Mechanical Engineering 3 5 Drilling And Tapping On Radial Drilling Machine 6 Shaping 7 Slotting 8 Surface Grinding CONTENTS metrology S. No. Name of the Experiment Page No. From To 1 Measurement of lengths heights diameters by Vernier calipers Micrometers etc. 2 Bevel Protractor 3 Internal Micrometer 4 Machine Tool Alignment Test On The Lathe 5 Tool maker’s microscope

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Geethanjali College of Engineering and Technology Department of Mechanical Engineering 4 Note: 1. At least ten experiments are to be performed in the semester. 2. At least FOUR experiments should be performed from the above list. Remaining two experiments may either be performed from the above list or designed set by the concerned institute as per the scope of the syllabus. PREFACE Industrial Revolution has given man a lot many luxuries and these are generally in the form of Mechanical Machines. The manufacturing of their parts is not a simple task and requires a lot of accuracy many times. This is not obtainable by any of the direct methods from the molten metal. Hence metal is obtained in a basic shape and size which is then machined to the exact required size. The Study of these metal removing operations is done under MACHINE TOOLS. The lab sessions are intended to make the students understand the different operations in machines such as Lathe Drilling Machine Milling Machine Grinding Machine etc. The student will be provided with a raw metal piece along with the dimensions of the required work piece. The Laboratory for MACHINE TOOLS complements the learning experience of the lecture. Laboratory exercises provide opportunities for direct study of the Machines and their operation. The laboratory must be used as a chance to enhance understanding of the Machining chip formation. The following Learning Objectives for the laboratory will guide you in taking an active role in your education. 1. Gain familiarity with physical use of Machines. You will perform operations to obtain Metal pieces in various shapes: Step Tapered Drilled etc. A student is required to observe the different characteristics of the tool such as: a. Rake. b. The effect of the speed feed depth of cut on type of chip formation.

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Geethanjali College of Engineering and Technology Department of Mechanical Engineering 5 These experiments give a first hand experience with Machining Operations. As a result of performing these experiments one should be able to understand the difficulties faced in obtaining the desired shape and reduce the errors if there are any to a maximum extent possible. Also one should follow all the instructions carefully and take all the precautions so none’s life is put under danger. 2. Develop and reinforce measurements skills. A student should know how to read the different scales with Vernier or Thimble scales for smaller readings. He must be able to find the Least count error in the given scale and use the information to obtain the correct angle or measurement for the given work piece. 3. Develop and reinforce skills in documenting observations. You should develop good habits in the organization and recording of raw data in a notebook and take care to document the data such that it can be analyzed at a later time. You should sketch the physical apparatus used in the experiment. In doing so pay special attention to the specific mechanical and operational details that enable the apparatus to achieve the purpose for which it was designed. You should be able to list and describe the steps used to obtain the desired measurements. You should be able to identify whether any actions were taken to improve the outcome of the experiment. Likewise you should be able to identify any actions that may have contributed to undesirable outcomes. 4. Develop skills at writing laboratory reports. You will create reports to document your measurements in the laboratory. You will usea writing style and format that is common to technical documentation used in Civil and Mechanical Engineering. Your reports should be complete yet concise. By writing the report you should develop a clear understanding of the laboratory exercise and communicate that understanding in your written words. LAB POLICY 1. GROUPS

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Geethanjali College of Engineering and Technology Department of Mechanical Engineering 6 Students will be formed into groups of three or four on the first lab day. Once a student has signed up with a group he or she may not change groups without prior approval of the instructor and the group people has to complete the experiment at a time. 2. LAB REPORTS You will perform the experiment in group and turn in ONE REPORT PER GROUP. Your report should be self-contained i.e. an engineering technologist should be able to perform the experiment and duplicate your results by reading your report. DO NOT "adjust" your data to make them fit what you believe to be an acceptable value. Your report should be an accurate description of the experiment. If your results differ significantly from reference values you should check your settings carefully calibration wrong units wrong calculations etc. and do the experiment again. Try to explain any discrepancies but do not "adjust" your data. In group every one should calculate different readings. At least minimum 5 reading has to be taken. 3. REPORT FORMAT: The report must be hand written. A report should include the following in order A. A title page which includes the following information in order: 1. Course Number and Section Number 2. Experiment Title 3. Names of the Group Members who contributed to do the lab/report 4. Due Date B. Objective or purpose of the experiment work. C. Theoretical aspect of the experiment. D. Experimental procedure that explains briefly the procedure of how the experiment was performed and all the equipment used. E. Experimental and/or calculated results. Include all data you have taken a sample calculation and the results The result table must be presented in tabular form. Also all calculations and graphical work e.g. graph must be hand written/drawn. F. Discussion of results in light of the theoretical “predictions”. Include an error analysis. Quantify the errors whenever possible. G. Conclusions wherein you write what you learned from the experiment. Your conclusions must summarize your report and must be based on your experimental results

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Geethanjali College of Engineering and Technology Department of Mechanical Engineering 7 Lab reports are due at the beginning of next lab. Late lab reports will not be accepted. Note: In order to get a good grade in the lab please follow the instructions listed below: 1. Read about the lab prior to the beginning of the lab. Do each lab with an attitude of learning. 2. Please bring your lab manual to the lab. Every one should have their laboratory manuals during the laboratory time. Otherwise they will not allow to do experiment. 3. Students are advised to bring blank and graph papers to the lab on which you can do calculations and draw graphs and attach them in the manual and laboratory record. Remember the lab grade is 20 of your final grade. Doing well in lab will help you in getting a good overall course grade. Remember “Nothing worthwhile will ever be achieved without deep thought and hard work” 4. ATTENDANCE: Attendance will be taken at the beginning of every lab session. 5. STRENGTH OF MATERIALS LAB POLICY: We want to maintain the high quality conditions of this lab for the students in future years. Thus it is necessary for you to adhere to the established policy of NO BEVERAGES FOOD NEWS PAPERS MAGAZINES TOBACCO PRODUCTS AND ANIMALS within the Strength of Materials lab. 6. SAFETY: For your own safety please wear the pants and shoes that cover toes for this Lab. The safety goggle will be needed for several labs. 7. GENERAL INSTRUCTIONS i. Every student should obtain a copy of the 55604 laboratory manual. ii. Dress code: Students must come to the laboratory wearing: 1 trousers ii apron and iii Leather shoes. iii. Half pants loosely hanging garments and slippers are not allowed. iv. To avoid any injury the student must take the permission of the laboratory staffs before handling the machines. v. EVERY STUDENT IS REQUIRED TO HANDLE THE EQUIPMENT WITH CARE. vi. Students must ensure that their work areas are clean.

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Geethanjali College of Engineering and Technology Department of Mechanical Engineering 8 vii. At the end of each experiment the student must take initials from the staff on your data/observations. Without submitting the day to day laboratory marks will not be given. viii. Laboratory report must be submitted in standard sheet available at stores in the subsequent lab turn. Reports on ordinary sheets and computer papers will not be accepted. ix. Each member of any group must submit lab report even if the experiment has been performed in a group. x. The lab report must contain: 1 Title of the experiment ii Three to four lines stating the objectives iii A few lines on background iii Name of all equipments/tools used along with one line description of its use and iv Neatly labeled sketches diagrams. xi. Student can check their laboratory reports after correction for discussion.

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Geethanjali College of Engineering and Technology Department of Mechanical Engineering 9 MACHINE TOOL LAB: Introduction to general purpose machines LATHE Lathe is the oldest machine tool and is used to remove material from a rotating work-piece on the form of chips with help of a tool traversed along the work-piece and can be fed deep in to the work. The tool material should be harder than the work-piece and the later held securely and rigidly on the machine. A lathe is used mainly to produce cylindrical surfaces and plane surfaces at right angles to the axis of rotation. Working: - A lathe basically consists of a bed to provide support headstock cross slide to traverse the tool. Tool post mounted on the cross slide. The spindle is driven by a motor through a gear box to obtain a range of speeds. The carriage moves over the bed guide ways parallel to the work-piece and the cross slide provides the transverse motion. A feed shaft and led screw are also provided to power the carriage and cutting the threads respectively. Machining operations: - The most common operations that can be performed on a Lathe machine are: Turning Facing Taper turning Eccentric turning Boring Drilling Reaming Threading Knurling etc. In addition to these with the help of special attachments operations like key-way cutting Cam and gear cutting shaping Milling Fluting Grinding can also be performed on this machine. Components of the Lathe Machine:

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Geethanjali College of Engineering and Technology Department of Mechanical Engineering 10 Main parts of a lathe machine includes Bed Head stock Tail stock Carriage Feed mechanism Screw cutting mechanism etc. Bed: - The lathe bed forms the base of the machine. Headstock and Tailstock are located at either end of the bed. Carriage and tailstock are free to move / slide on bed where as headstock I fixed rigidly. Headstock: - The headstock consists of the head stock casting which is located on the ways of the bed at the left side of the operator the hollow spindle in which the live center I held rigidly by taper and gears and mechanism for obtaining various spindle speeds A head stock may be driven either from a line shaft or from an independent motor . The drive being transmitted to the constant speed main drive pulley. A separate speed change gear box is placed below the head stock to reduce the speed in order to have different rate of feed for threading and automatic lateral movement of the carriage. Tailstock: - It I located on the inner guide vanes of right hand end of the lathe bed. It can move freely on the guide ways provided on the lathe bed is used mainly to support the work piece while machining if the free length of the work-piece is large and also to hold some special tools such as drill bit taper bit boring tool etc. Carriage: - The carriage of the lathe contains several parts that serve the purpose to support move and control cutting tool. It consists of the following parts 1. Saddle 2. Cross slide 3. Compound rest 4. Tool post 5. Apron 6. Half-nut mechanism etc. Saddle is an H shaped casting that fits over the bed and slides along the guide ways. It carries the cross slide and the tool post. Cross slide comprises a casting machined on the underside for attachment to the saddle and carries location on the upper face for the tool post or the compound rest. Cross slide had wheel is graduated on either sides or a separate micrometer dial may be4 fitted on them so that a known amount of feed can be applied. Compound rest supports the tool post and cutting tool in it in various positions. It may be swiveled on the cross slide to any angle in the horizontal plane its base being graduated suitably. A compound rest is necessary in turning angles and boring short tapers and in turning angles and forms a forming tool. Tool post is used to hol the variouscutting tools and holders. Feed Mechanism:- The movement of the tool along the length of the work piece is called as feed. In lathe feed can be obtained by any of these the mechanisms: Gearing at the end of the bed Feed gear box Feed rod and lead screw Apron mechanism

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Geethanjali College of Engineering and Technology Department of Mechanical Engineering 11 Screw cutting mechanism: - Screw cutting mechanism is mainly obtained by the lead screw to get thread cutting on the work-piece. The pitch of the thread is controlled by the speeds of the headstock spindle and the lead screw. Specifications of the LATHE Usually a Lathe is specified by: 1. Distance between the two centers of the lathe 2. Swinging diameter over the bed 3. The largest diameter of the work-piece that can be revolved in the chuck without touching the bed 4. Height of the live and dead centers 5. Swinging diameter over the carriage This is the largest diameter of the work-piece that can revolve over the lathe saddle and it always less than swinging diameter over the bed 6. The maximum bar diameter this is the maximum diameter of the bar stock that will pass through the spindle hole 7. Length of the bed this indicates the approximate space on the floor by the lathe. 8. The power required by the lathe

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Geethanjali College of Engineering and Technology Department of Mechanical Engineering 16 SHAPER The shaper is the reciprocating type of machine tool intended primarily to produce flat surfaces these surfaces may be horizontal vertical or inclined Working of shaper: The shaper makes use of a single point tool that traverse the work and feeds over at the end of each stroke. It is used principally to machine flat or plane surfaces in

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Geethanjali College of Engineering and Technology Department of Mechanical Engineering 17 horizontal vertical or inclined planes. The cutting tool is mounted on the shaper head to the ram. The ram imparts reciprocating motion to the tool which operates over the shaper table. A big advantage of it is that since the amount of metal at one time is relatively small in area therefore little pressure is imparted upon the work and the elaborate holding fixtures are not needed. Vertical cuts can be taken by feeding the tool with the shaper head slide. The shaper head can be set at an angle in order to take angular cuts. Operations of shaper: While producing flat surfaces on the shaper it is observed that when tool comes into contact with the job it digs in to the job and therefore the edges are gradually not flat but slightly over curved. Some effect is observed at the end edges also. Due to its limited length of stroke it is conveniently adopted to the small jobs and best suited for the surfaces composed of straight line elements and for batch production. It can produce all types of surface finishes. The set up time and change over time are less as intricate fixtures and supporting devices are replaced by simple holding gadgets. It is also bets suited for cutting keyways and splines on shafts. Principal parts of shaper: Base: The base is the necessary support or bed referred from all machine tools. It is also designated that it can take up the entire load of the machine and forces set by the cutting tool over the work. It is made up of cast iron to resist vibration and take up high compressive load. Column: It is a box like casting mounted on the bas. It encloses the ram guiding mechanism. Two accurately machine guide ways are provided on the top of the column which the ram reciprocates. The front vertical face of the column has the guide ways for the cross load. The other side of the column contains levers handles for operating the machine. Cross rail: It has two parallel guide ways on its top in a vertical plane that is perpendicular to ram axis. The table may be raised or lowered to accommodate different sized jobs by rotating elevating screw which causes the cross rail to slide up and down on the vertical face of the column. Rotary table: It is a circular table which is mounted on the top of cross slide. The table may be rotated by rotating a screw which meshes with the warm gear connected to the under side of the table. The rotation of the table affected either by hand or power. In some machines the table is graduated in degrees. That enables the table to be rotated for indexing in dividing the periphery of a job in equal number of parts. ‘T’ slots are provide on the top face of the table for holding the work by different clamping devices.

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Geethanjali College of Engineering and Technology Department of Mechanical Engineering 18 Specifications of the SHAPER 1 The size of the shaper is specified by the maximum length of stroke that it can cut. The usual size ranges from 175mm to 900mm. 2 According power feed which ranges from 0.2mm to 5mm per stroke. 3 The power of the motor. SLOTTING MACHING

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Geethanjali College of Engineering and Technology Department of Mechanical Engineering 19 The Slotting machine falls under the category of reciprocating type of machine tool similar to a Shaper or a Planer. Working of Slotter: It operates almost on the same principle of a Shaper. The major difference between a Slotter and Shaper is that in a Slotter the ram holding the tool reciprocates in a vertical axis where as in Shaper the ram holding the tool reciprocates in a horizontal direction. Operations of Slotter: Machining flat surfaces cylindrical surfaces machining irregular surfaces and cam machining machining slots keyways and grooves etc. Principal parts of Slotter: Base: The base is rigidly built to take up all the cutting forces and entire load of the machine. The top of the bed is accurately finished to provide guide ways on which the saddle is mounted. Column: The column is a vertical member which is cast integral with the base and houses driving mechanism of the ram and feeding mechanism. Saddle: It is mounted up on the guide ways may be moved toward or away from the column either by power or manual control to supply longitudinal feed to the work. Cross slide: The cross-slide is mounted upon the guide ways of the saddle and may be moved parallel to the face of the column. Rotary table: The rotary table is a circular table which is mounted on the top of the cross slide. The table may be rotated by rotating a worm which meshes with a worm gear connected to the underside of the table. The rotary table enables a circular or contoured surface to be generated on the work-piece. Ram and tool head assembly: The ram is reciprocating member of the machine mounted on the guide ways of the column. It supports the tool at its bottom end on a tool head. Ram drive mechanism: A slotter removes metal during downward cutting stroke only where as during upward return stroke no metal is removed. To reduce the idle return time quick return mechanism is incorporated in the machine. Specifications of the Slotter:

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Geethanjali College of Engineering and Technology Department of Mechanical Engineering 20 The size of the Slotter like that of a shaper is specified by the maximum length of the stroke of the ram expressed in mm. The size of a general purpose or precision slotter usually ranges from 80 to 900mm. To specify a slotter correctly the diameter of the table in mm amount of cross and longitudinal travel of the table expressed in mm number of speeds and feeds available H.P of the motor floor space required etc. DRILLING MACHINE The drilling machine is one of the most important machine tool in the work shop. In drilling machine holes may be drilled quickly and also at low cost. The hole is generated by the rotating edge of a cutting tool known as the drill bit which exerts large force on the work piece clamped on the table. Working of drilling machine: Drilling I a process of making holes or enlarging a hole in a object for forcing a rotating tool called drill. The same operation can be accomplished in some other machines by holding the drill stationary and rotating the work. The most general

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Geethanjali College of Engineering and Technology Department of Mechanical Engineering 21 example of this case is drilling hole in lath in which the drill is held in the tail stock and the work I held and rotated in the chuck. Boring is the process of enlarging a hole that has already drilled. Principally it is an operation of turning a hole that ha been drilled previously with a single point tool. To perform this operation on drilling machine a special holder for the boring tool is required. Operations of drilling machine: Although the drilling machine is mainly meant for drilling operation it can also be used for performing the operations like Reaming Boring Counter boring Counter sinking Spot facing Tapping Trepanning Rivet spinning polishing etc. Principal parts of drilling machine: Base Column Radial arm Drill head Feed mechanism Specifications of the drilling machine 1.The size of the portable drilling machine is specified by the maximum diameter of the drill that which can hold. 2. Sensitive and Up right drilling are specified by the diameter of the largest hole that it can be drilled. 3.The radial drilling machine is specified by the length of the arm and column diameter. 4.Multiple spindle drilling machine is specified by the drilling area the size and the number of holes that the machine can drill.

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Geethanjali College of Engineering and Technology Department of Mechanical Engineering 24 MILLING MACHINE A milling machine finds wide applications in production work. This is superior to other machines as regards accuracy and better surface finish and is designed for machining a variety of tool room work. Working of Milling Machine: A Milling machine is a machine tool that removes metal as the work is fed against a rotating multi point cutter. The cutter rotates at a high speed and because of the multiple cutting edges

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Geethanjali College of Engineering and Technology Department of Mechanical Engineering 25 it removes metal at a very fast rate. The machine can also hold one or more number of cutters at a time. Operations on Milling Machine: Plain Milling Face milling Side milling Straddle milling Angular milling Gang milling Form milling Profile milling End milling Saw milling Milling key ways grooves and slots Gear cutting Helical milling Cam milling Thread milling etc. Principal parts of Milling Machine: Base: The base is the machine is a grey iron casting accurately machined on its top and bottom surface and serves as a a foundation member for all the other parts which rest upon it. It carries the column at its one end. Column: The column is the main supporting frame mounted vertically on the base. The column is box shaped heavily ribbed inside and houses all the driving mechanisms for the spindle and the table feed. Knee: The knee is a rigid grey iron casting that slides up and down on the vertical ways of the column face. The adjustment of height is effected by an elevating screw mounted on the base that also supports the knee The knee houses the feed mechanism of the table and different controls to operate it. The top face of the knee forms a slide way for the saddle to provide cross travel of the table. Table: The table rests on the ways on the saddle and travels longitudinally. A lead screw under the table engages a nut on the saddle to move the table horizontally by hand or power. In universal machines the table may also be swiveled horizontally. For this purpose the table is mounted on a circular base which in it turn is mounted on the saddle. Overhanging arm: The overhanging arm that is mounted ion the top of the column extends beyond the column face that serves as a bearing support for the other end of the arbor. Front brace: The front brace is an extra support that is fitted between the knee and the overarm to ensure further rigidity to the arbor and the knee. The front brace is slotted to allow for the adjustment of the height of the knee relative to the over arm. Spindle: The spindle of the machine is located in the upper part of the column and receives power from the motor through belts gears clutches and transmit it to the arbor. The front end of the spindle just projects from the column face and is provided with a tapered hole into which various cutting tools and arbors may be inserted. The accuracy in metal machining by the cutter depends primarily op the accuracy strength and rigidity of the spindle. Arbor: The arbor may be considered as an extension of the machine spindle on which milling cutters are securely mounted and rotated the arbors are made with taper shanks for

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Geethanjali College of Engineering and Technology Department of Mechanical Engineering 26 proper alignment with the machine spindles having taper holes at their nose. The taper shank of the arbor confirms to the Morse taper or self release taper whose value is 7:24. The arbor may be supported at the farthest end from the overhanging arm or may be of cantilever type which is called stub arbor. Specifications of the Milling Machine: The size of the column and knee type milling machine is designated by the dimensions of the working surface of the table and its maximum length of longitudinal cross and vertical travel of the table. In addition to above dimensions number of spindle speed number of feed spindle nose taper Power available net weight and the floor space required etc. should also be stated in order to specify the milling machine fully.

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Geethanjali College of Engineering and Technology Department of Mechanical Engineering 27 GRINDING MACHINE Grinding in accordance with the type of surface to be ground is classified as : a. External cylindrical grinding b. Internal cylindrical grinding c. Surface grinding d. Form grinding.. Grinding machines according to the quality of the surface finish may be classified as i. Rough grinders ii. Precision grinders. Working of Grinding Machine: Grinding is the metal cutting operation performed by means of rotating abrasive wheel that acts as a tool. This is used to finish the work pieces which must show a high surface quality accuracy of shape and dimension Operations of Grinding Machine: Grinding of surfaces like external cylindrical grinding Internal cylindrical grinding Surface grinding Form grinding rough grinding Precision grinding roll grinding Cam grinding grinding of cutting tools sharpening cutters etc. Principal parts of Grinding Machine: Base: The base or bed is the main casting that rests on the floor and supports the parts mounted on it. On the top of the base a precision horizontal ways set at right angles for the table to slide on. The base also houses the table-drive mechanism. Tables: There are two tables lower table and upper table. The lower table slides on the ways on the bed provides traverse of the work past the grinding wheel. It can be moved by hand or

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Geethanjali College of Engineering and Technology Department of Mechanical Engineering 28 power within the desired limit. The upper table is pivoted at its center is mounted on the top of the sliding table. It can be swiveled and clamped in position to provide adjustment for grinding straight or tapered work as desired. Setting for tapers up to ±10¬¬¬0 can be made in this ways. Head stock: The head stock supports the work by means of a dead center and drives it by means of a dog or it may hold and drive the work piece in a chuck. Tailstock: The tailstock can be adjusted and clamped in various positions to accommodate different lengths of workpieces Wheel head: The wheel head carries a grinding wheel and its driving motor is mounted on a slide at the top and rare of the base. The wheelhead may be moved perpendicularly to the table ways by hand or power to feed the wheel to the work. Cross feed: The grinding wheel is fed to the work by hand or power as determined by the engagement of the cross feed control lever. Selection of Grinding Wheels: There are four constant factors in selection of a grinding wheel. They are 1. The material to be ground 2. Amount of stock to be removed 3. Area of contact 4. Type of grinding wheel. Specifications of the Grinding Machine: Grinding machine size is specified according to the size of the largest work piece that can be mounted on the machine.

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Geethanjali College of Engineering and Technology Department of Mechanical Engineering 29 Plain Turning Experiment No. 1 STEP TURNING OPERATION Aim: To perform a step turning operation on the given cylindrical work piece. Apparatus: 1. Lathe with standard accessories. 2. Work piece

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Geethanjali College of Engineering and Technology Department of Mechanical Engineering 30 Principle: Turning is a lathe operation in which an external cylindrical surface is produced by generating. The cutting Tool is first adjusted for the desired depth of cut using the cross slide. Then as the work piece rotates the cutting tool is advanced relatively slowly I a direction parallel to the rotational axis of the spindle. The motion is known as the feed. These combined motions cause the work piece by adjusting the feed so that the helical path of the tool tip overlaps and generates a cylindrical surface on the work piece. A spindle rpm which gives a desired cutting speed at the circumference of the cylindrical surfaces should be reflected. This may be calculated using the following formula: Spindle speed RPM∏dN/1000 Feed is measured as advance of the cutting tool per revolution of the work piece. Tools: Steel rule outside calipers tool holder with key chuck key HSS cutting Tool bit. Material: Mild Steel round rod of diameter 20 mm Procedure: Initially the given work piece is fitted the chuck using a chuck key. The high speed tool bit is positioned in the tool cutting is kept at an angle to the axis of the given work piece. During this process positioned in the tool holder the speed of the lathe is high. After this operation the diameter of the work piece is to be reduced according to the given dimensions by turning process. While doing the work piece one end of the work piece is reduced to the required diameter and after this chamfering. Process if performed by burning the tool but at 45O inclination and by bringing the tool in contact with the edge of the job this process removes all sharp edges of the component. Precautions: 1. The chuck key must be removed immediately after the use.

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Geethanjali College of Engineering and Technology Department of Mechanical Engineering 31 2. The power supply switched off before measuring diameter. 3. Before performing facing they must be in same line. Result: The required steps are made on the work piece for the given dimensions.

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Geethanjali College of Engineering and Technology Department of Mechanical Engineering 32 Experiment No. 2 TAPER TURNING OPERATION Aim: Test Procedure to perform Taper turning operation by Compound Rest Swiveling method on the given cylindrical work piece. Apparatus: 1. Lathe with standard accessories. 2. Work piece Principle: Cutting Tapers on a lathe is common application. A number of methods are available for cutting tapers on a lathe. They are: 1. Compound rest Swiveling Method. 2. Using form tools. 3. Tail stock offset method. 4. Taper attachment method. These methods are used for turning steep and short tapers. There is a circular base graduated in degrees which can be swiveled at any angle from the center line of the lathe centers. The amount of taper in a work piece is usually specified by the ratio of the difference in diameters of the taper to its length. This is termed as conicity and is designated by the letter K. Conicity K D-d/2xl Tools:

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Geethanjali College of Engineering and Technology Department of Mechanical Engineering 33 Chuck key high speed Steel HSS cutting tool bit outside calipers Tool Holder with key spanner etc. Material: Mild Steel round rod of diameter 20 mm Procedure: The work piece is fixed in the tool post tightly and the center of head stock and tail stock is coincided with the centers of head stock and tail stock. Facing and plain turning operations are performed to get the required diameter on the work piece. The compound rest is set on the required half taper angle and is locked by the cutting rod is adjusted to a fixed position for the best possible to the open hand wheel and cross feed. Then the carriage is locked and first cut is made at the end of the cut the tool is again cross fed is given for the next cut. Cuts are repeated piece is then removed from the chuck and dimensions obtained are noted. Precautions: 1. The work piece should be fixed tight in the jaw. 2. The power supply switched off before measuring diameters. Result: The required steps are made on the work piece for the given dimensions.

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Geethanjali College of Engineering and Technology Department of Mechanical Engineering 35 Experiment No. 3 TAPER TURNING AND KNURLING OPERATIONS Aim: Test Procedure to perform Taper turning operation by Compound Rest Swiveling method on the given cylindrical work piece. Apparatus: 1. Lathe with standard accessories. 2. Work piece Principle: Cutting Tapers on a lathe is common application. A number of methods are available for cutting tapers on a lathe. They are: 1. Compound rest Swiveling Method. 2. Using form tools. 3. Tail stock offset method. 4. Taper attachment method. These methods are used for turning steep and short tapers. There is a circular base graduated in degrees which can be swiveled at any angle from the center line of the lathe centers. The amount of taper in a work piece is usually specified by the ratio of the difference in diameters of the taper to its length. This is termed as conicity and is designated by the letter K. Conicity K D-d/2xl Tools: Chuck key high speed Steel HSS cutting tool bit outside calipers Tool Holder with key spanner etc. Material: Mild Steel round rod of diameter 20 mm.

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Geethanjali College of Engineering and Technology Department of Mechanical Engineering 36 Procedure: The work piece is fixed in the tool post tightly and the center of head stock and tail stock is coincided with the centers of head stock and tail stock. Facing and plain turning operations are performed to get the required diameter on the work piece. The compound rest is set on the required half taper angle and is locked by the cutting rod is adjusted to a fixed position for the best possible to the open hand wheel and cross feed. Then the carriage is locked and first cut is made at the end of the cut the tool is again cross fed is given for the next cut. Cuts are repeated piece is then removed from the chuck and dimensions obtained are noted. Precautions: 1. The work piece should be fixed tight in the jaw. 2. The power supply switched off before measuring diameters. Result: The required steps are made on the work piece for the given dimensions.

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Geethanjali College of Engineering and Technology Department of Mechanical Engineering 37 Experiment No. 4 RIGHT HAND SCREW THREAD CUTTING AND KNURLING OPERATION Aim: To obtain a Right Hand Screw threaded workpiece of given dimensions. Apparatus: 1. Lathe with standard accessories. 2. Work piece Material: Mild Steel round rod of diameter 20 mm Procedure: The given workpiece is fixed tightly in the 3 jaw chuck. Facing and turning operations are done to make the diameter equal to the major diameter of the screw thread. According to the given Pitch the necessary gearing ratio is calculated. The feed selection lever that unlocks the half-nut lever for use is set on the carriage apron for cutting metric threads the included angle of the cutting edge should be ground exactly 60 O the thread cutting tool is fixed in the tool post so that the tip of the tool coincides with the axis of the workpiece the lathe spindle speed is reduced by on half on forth of the speed required for turning by back gear mechanism or quick change levers. The half nut lever engaged at the end of the cut the spirit nut lever disengages the carriage and the tool is withdrawn to its position sufficient depth is given for each cut using the cross slide the process is repeated till the required dimensions are obtained. Precautions: 1. For cutting right threads the change gears should be so arranged that the direction of the lead screw is in same direction as that of the rotation of spindle. 2. The work piece should be fixed tight in the jaw. 3. The power supply switched off before measuring diameters. Result: Right Hand thread with required pitch is produced on the given workpiece.

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Geethanjali College of Engineering and Technology Department of Mechanical Engineering 38 Experiment No. 5 DRILLING AND TAPPING ON RADIAL DRILLING MACHINE Aim: To perform drilling reaming and tapping operations on the given M.S Flat workpiece. Apparatus: 1. Drilling Machine with standard accessories 2. Work piece Material: Mild Steel round rod of diameter 20 mm. Procedure: 1. The given workpiece is first fitted to get required length breadth and thickness wet chalk is applied on four sides and with the scriber lines are drawn to get center hole at required location. 2. The centers are punched with a Punch and hammer. 3. The workpiece is fixed firmly in the vice of the Drilling Machine 4. 3/8” drill bit is fixed firmly in the chuck and drilling is performed giving uniform depths. 5. The drill bit is removed from the drill chuck and is replaced by a reamer. 6. The reaming operation is performed on the hole which has been previously drilled. 7. The work is removed from the vice for performing tapping operation. 8. The job is fixed firmly in a bench vice. 9. Tap is fixed in the tap handle and pressure applied on the taps to obtain internal thread. Precautions: While performing reaming and tapping operations lubricant should be used to minimize friction. Result: Drilling Reaming and Tapping operations are performed on the given work piece as per given dimensions.

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Geethanjali College of Engineering and Technology Department of Mechanical Engineering 39

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Geethanjali College of Engineering and Technology Department of Mechanical Engineering 40 Experiment No. 6 MILLING OF HEXAGONAL SURFACE AIM : To machine a given hexagonal surface in a given workpiece using milling machine. TOOLS AND EQUIPMENTS REQUIRED : Milling Machine Vernier caliper Steel rule Mandrel PROCEDURE : 1. The given workpiece is checked for its dimensions. 2. The width across the flat is first determined Across flat 1.5 S + 3 mm 3. A universal dividing head is mounted on the table with its spindle swiveled to the horizontal position. 4. The workpiece is mounted at the nose of the dividing head spindle by the help of a suitable chuck. 5. The workpiece is centered below the cutter and the first cut is taken. 6. The workpiece is rotated through one sixth of a revolution by using the indexing mechanism and then the second cut is taken. It is to be repeated for six number of times to finish six faces of the workpiece. RESULT : Thus the required hexagonal surface is machined using the milling machine to the given dimensions.

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Geethanjali College of Engineering and Technology Department of Mechanical Engineering 41 CALCULATION : Diameter D 2 x S Distance across the Flat 1.5 x S + 3mm Diameter D – Distance across the Flat Depth of cut ----------------------------------------------------- 2 INDEXING CALCULATION : For Hexagonal surface the number of faces Z 6. 40 Simple Indexing ---- Z S20

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Geethanjali College of Engineering and Technology Department of Mechanical Engineering 42 Experiment No. 7 SHAPING AIM: To machine maximum size of square from a given cylinder work piece by using the shaping machine. Tools required: vice tool scale etc Apparatus: shaping tool lubricating oil circular shape w/p punch hammer steel rule CALCULATIONS: Cos45 x/2/ d/2. X/2 D/2 cos45 X 2 x/2. Each side to get width XD-X/2. SPECIFICATIONS: Capacity: Length of arm without tool side 775 mm Length of stoke 400 mm Length of working stoke 375 mm Maximum distance from table to arm 345 mm Ram adjustment 180 mm

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Geethanjali College of Engineering and Technology Department of Mechanical Engineering 43 Table:- Table size lwh 325225230 mm 3 Working area on the table 225380 mm Table displacement vertically 310 mm Horizontally 455 mm Tool Head:- Tool Slide Travel 160 mm Tool Slide Tilting 600 - 00 600 THEORY:- Shaper in a vertical machine which is primarily intended for producing flat surfaces. This machine involves the use of single point tool head in a properly designed tool box mounted on reciprocating ram. In case of a shaper the job rigidly held in a vice on the machine table. The tool is held in the tool post mounted on the ram of the machine. This ram reciprocates to and fro and in doing so makes the tool to cut the machine in forward direction no material is removed during the return stoke of the ram hence it is termed as a ideal stoke. SEQUENCE OF OPERATIONS: 1. Marking on the work piece. 2. Hold the work piece. 3. Adjust stroke length. 4. Adjust ram position. 5. Each side D-X/2 metal is removed by step by step. PROCEDURE: 1. MEASURING AND MARKING: For a given diameter of the circular work piece. Calculate side of a square and locate the centre. Mark the square with the help of punch and hammer by drawing the diagonals. 2. TOOL SETTING: The tool is held in the tool post mounted on the ram of the machine. 3. JOB FIXING: The job is rigidly held in a vice. Now adjust the table so that the highest portion of the circular part should exactly coincide with the tip of the tool.

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Geethanjali College of Engineering and Technology Department of Mechanical Engineering 44 4. SHAPING: By selecting a suitable depth of cut start the machine to remove the material. Feed should be given to the table either by hand or by using power. Note down the number of passes required to complete the side of a square. 5. Depth of cut should be increased rapidly during return stroke. 6. After completion of one side rotate the job and repeat the above procedure till completion of a square piece. PRECAUTIONS: 1. The depth of cut should be given at small rates. 2. Lubrication should be provided for reciprocating and other moving parts. 3. Remove the chips continuously from the work surface or table. 4. It should be seen that always quick return motion is achieved.

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Geethanjali College of Engineering and Technology Department of Mechanical Engineering 45 Experiment No. 8 MILLING AIM: To machine a slot on a given work piece as shown in figure by using milling machine. TOOLS REQUIRED: Side face cutter standard arbor spacers vice. APPARATUS: Milling Machine Steel Rule Punch Hammer Number Punch SELECTION OF RPM: VπDN/1000 Where • V cutting speed m/min selected based on work tool combination from data book. • D dia of cutter. • N rpm of cutter. N V×100/πD • Depth of cut 0.5 to 1mm • Type of milling Up milling. • Feed given manually.

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Geethanjali College of Engineering and Technology Department of Mechanical Engineering 46 SPECIFICATIONS: • Surface of the table 1050 250 mm • Distance between the t-slots 62 mm • Longitudinal travel table 600 mm • Gross travel of the table 230 mm • Metrical adjustment of table 450 mm • Distance b/w center of spindle to Lower surface of the over arm115 mm • Taper in spindle IS040 STD • Diameter of Milling Arbor 254 mm • Range of spindle speeds. No 6 • R.P.M 65 To 525 SEQUENCE OF OPERATION: 1. Hold the work piece in vice. 2. Select the cutting speed. 3. Remove the metal by layer layer each depth of cut. PROCEDURE: Milling of an 8×2 groove on the given work piece involves the following steps. MEASURING AND MARKING: The given work piece is checked for the required dimensions. Filing is done in order to get the flat surface and to obtain the required dimensions of the job. Marking is done on the work piece with the help of punch and hammer. TOOL SETTING: The required multi point cutting tool is placed in the arbor of a milling machine to perform the operation. JOB FIXING: The job is fitted in the jaws provided on the table and raises the table so that the work piece is in contact with the cutting tool. MILLING: Now select a suitable depth of cut in terms of a known value and raise the table based on the graduations provided on the dial.

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Geethanjali College of Engineering and Technology Department of Mechanical Engineering 47 Start the machine so that the tool rotates in clock wise direction. The feed is given to the work table in the direction opposite to cutter direction. This milling is termed as up milling. Increase the depth of cut at successive intervals and repeat the same procedure until we get the required groove on the job. The supply is to be switched off. PRECAUTIONS: 1. Before starting the process select the suitable type of milling either up milling or down milling. 2. Depth of cut should be given in small quantities. 3. The fed should be given slowly.

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Geethanjali College of Engineering and Technology Department of Mechanical Engineering 48 Experiment No. 9 SLOTTING AIM: To machine slots on a given hallow work piece as shown on the figure using slotting machine. TOOLS: Slotting tool steel rule chuck with dividing head etc DIVIDING HEAD DETAILS: Gear ratio 36:1 No of slots to be cut4 1 crank rotation the spindle rotation1/36×36010 To turn work piece by 90 the crank should be rotated 9 full rotations SEQUENCE OF OPERATION: 1. Hold the work piece in the chuck. 2. Pick up the tool and align the work piece center. 3. Adjust stroke length. 4. Complete the slotting at present position.

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Geethanjali College of Engineering and Technology Department of Mechanical Engineering 49 5. Index the job for next position. 6. Complete at all position. PROCEDURE: 1. The given work piece is placed in the vice by clamping the jaws. 2. The ram is adjusted so that the tool bit is placed inside the work piece hole and just touches the end. 3. Depending on slot size the depth of cut is given by hand wheel. 4. Now rotate the work piece exactly at 90 by using the index plate mechanism .i.e. rotate the index plate by 9 turns to get the required position. 5. Repeat the above procedure for the required four slots. PRECAUTIONS: 1. Care should be taken while locating the centre position for the work piece. 2. The position of work piece in the clamp is such that the ram must passes through the entire hole of work piece.

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Geethanjali College of Engineering and Technology Department of Mechanical Engineering 50 METROLOGY LAB Experiment No. 1 1. a. Vernier calipers Aim: To measure the dimension of a given specimen using Vernier Calipers Instruments required: Vernier Calipers given specimen. Theory: Vernier calipers are employed for both internal and external measurements. It can also be preset to a given measurement for checking dimension of a component. Principle: The principle of vernier is based on the difference between two scales or divisions which are nearly but not quite alike for obtaining small difference. If enables to enhance the accuracy of measurement. Fig.1.Vernier Calipers Construction: The vernier caliper consists of two scales: one is fixed and the other is movable. The fixed scale called main scale is calibrated on L-shaped frame and carries a fixed jaw. The movable scale called vernier scale slides over the main scale and carries a movable jaw. The movable jaw as well as the fixed jaw carries measuring tip. When the two jaws are closed the zero of the vernier scale coincides with the zero of the main scale. For precise setting of the movable jaw an adjustment screw is provided. Also an arrangement is provided to lock the sliding scale on the fixed main scale. Least Count of Vernier Instruments: Vernier instruments have two scales: Main scale and the Vernier scale. The main scale is fixed and the vernier scale slides over the main scale.

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Geethanjali College of Engineering and Technology Department of Mechanical Engineering 51 When zero on the main scale coincides with the zero on the vernier scale the vernier scale has one more division than that of the main scale with which it coincides. So the value of a division on vernier scale is slightly smaller than the value of a division on the main scale. This difference is the least count. Least count L.C. is the difference between the value of main scale division and vernier scale division. Thus least count of a vernier instrument Value of the smallest division on the main scale - The value of the smallest division on the vernier scale. Fig. 1 illustrates the principle of vernier scale and gives a clear idea about its least count. The value of smallest division on the main scale is 1 mm. Fig. 1shows that 50 divisions on the vernier scale coincides with 49 divisions on the main scale. Therefore the value of smallest division on vernier scale 49/50 mm. Thus least count value of smallest division on main scale - value of smallest division on vernier scale. i.e. L.C. 1 – 49/50 0.02 mm. The least count can also be calculated by the ratio of the value of minimum division on the main scale to the number of divisions on the vernier scale in this case L.C. 1/50 0.02 mm. Procedure: 1. Before using the instrument it should be checked for zero error. The zero line on the vernier scale should coincide with zero on the main scale. If this does not happen then error is present in the micrometer which must be taken into account while taking the readings. 2. The least count of the vernier is calculated. Least count Minimum division on the main scale / No. of divisions on the vernier scale 3. Place the specimen to be measured in between the measuring jaws. 4. Note the reading in mm on the main scale to the left of zero on sliding scale. 5. Now count the number of divisions on the vernier scale from zero to a line which exactly coincides with any line on the main scale. 6. Total reading can be calculated as follows. Total reading M.S.R. + V.S.R X L.C

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Geethanjali College of Engineering and Technology Department of Mechanical Engineering 52 Precautions: i. While measuring outside diameters with vernier calipers the plane of the measuring tips of the caliper must be perpendicular to the center line of the work piece. The calipers should not be tilted or twisted. ii. Grip the instrument near or opposite to the jaws and not by the overhanging projected main bar of caliper. iii. Move the caliper jaws on the work with light touch. Do not apply undue pressure. iv. The measuring instrument must always be properly balance in hand and held tightly in such away that only fingers handle the moving and adjusting screws. OBSERVATIONS:- Main Scale Reading M.S.R Vernier Scale Reading V.S.R Least Count L.C Total Reading M.S.R + V.S.R X L.C S.No. Component to Linear M.S.R. V.S.R. Least Total Reading L 1 L 2 L 3

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Geethanjali College of Engineering and Technology Department of Mechanical Engineering 53 be Measured Measurement Count T.R M.S.R + L.S.R. L.C. 1. 2. 3. 4. 5. 6. RESULT: The dimensions of the given component are ________________________ 1. b. Vernier Height Gauge Aim: To measure the height of a given specimen using a Vernier height gauge Equipment: Vernier height Gauge Theory: Vernier height gauge is similar to vernier calipers but in this instrument the graduated bar is held in vertical position and it is used in conjunction with a surface late.

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Geethanjali College of Engineering and Technology Department of Mechanical Engineering 54 Construction: A vernier height gauge consists of i A finely ground and lapped base. The base is massive and robust in construction to ensure rigidity and stability. ii A vertical graduated beam or column supported on a massive base. iii Attached to the beam is a sliding vernier head carrying the vernier scale and a clamping screw. iv An auxiliary head which is also attached to the beam above the sliding vernier head. It has fine adjusting and clamping screw. v A measuring jaw or a scriber attached to the front of the sliding vernier. It is designed for accurate measurements and making of vertical heights above a surface plate datum. It can also be used to measure difference in heights by taking the vernier scale readings at each height determining the difference by subtraction. OBSERVATIONS:- Main Scale Reading M.S.R Vernier Scale Reading V.S.R Least Count L.C Total Reading M.S.R + V.S.R X L.C H 1 H 2 H 3

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Geethanjali College of Engineering and Technology Department of Mechanical Engineering 55 S.No. Component to be Measured Linear Measurement M.S.R. V.S.R. Least Count Total Reading T.R M.S.R + L.S.R. L.C. 1. 2. 3. 4. RESULT: The dimensions of the given component_______________ 1.c Micrometer Aim: To measure the diameter of a given specimen using micrometer. Equipment used: Micrometer specimen Theory: Micrometer is one of the most common and most popular forms of measuring instrument or precise measurement. Principle of Micrometer:

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Geethanjali College of Engineering and Technology Department of Mechanical Engineering 56 Micrometers work on the principle of screw and nut. We know that when a screw is turned through nut through one revolution it advances by one pitch distance i.e. one rotation of screw corresponds to a linear movement of a distance equal to pitch of the thread. If the circumference of the screw is divided into number of equal parts say ‘n’ its rotation through one division will cause the screw to advance through ł Ł n Pitch length. Thus the minimum length that can be measured by such arrangement will be ł Ł n Pitch . By reducing the pitch of the screw thread or by increasing the number of divisions on the circumference of screw the length value of one circumferential division can be reduced and accuracy of measurement can be increased considerably. Least Count of Micrometer Least count is the minimum distance which can be measured accurately by the instrument. The micrometer has a screw of 0.5 mm pitch with a thimble graduated in 50 divisions to provide a direct reading of ł Ł n Pitch 50 50 . 0 0.01mm Least count of a micrometer is thus the value of one division on a thimble which is connected to the screw. L.C. of micrometer spindle on the divisions of Number screw spindle the of Pitch Micrometers can be classified as i outside micrometer ii inside micrometer iiiScrew thread micrometer iv Depth gauge micrometer. The following figure illustrates an external micrometer. It is used to measure the outside diameter and length of small parts to an accuracy of 0.01mm. Procedure: 1. Select the micrometer with a desired range depending upon the size of the work piece to be measured. 2. Before using the instrument it should be checked for zero error. The zero on the thimble should coincide with the zero on the reference line on the main scale. If this does not

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Geethanjali College of Engineering and Technology Department of Mechanical Engineering 57 happen then zero error is present in the micrometer which must be taken into account while taking the readings. 3. The barrel has graduations in intervals of 1mm above the reference line. There are also graduations below the reference line at the middle of two successive upper graduations so as to read 0.5mm. 4. For measuring the particular dimension hold the work between the faces of the anvil and spindle then move the spindle by rotating the thimble until the anvil and spindle touches the work surface. Make fine adjustment with the ratchet now take the reading on the main scale taking into account the divisions below the reference line. 5. Take the thimble reading which coincides with the reference line on the sleeve. 6. Total reading M.S.R. + T.R. x L.C OBSERVATIONS:- M.S.R Main Scale Reading T.R Thimble Reading L.C Least Count Total Reading M.S.R + Thimble Reading L.C S.No. Component to be Measured Diameter M.S.R. Thimble Reading Least Count Total Reading T.R M.S.R + T.R. L.C. 1. 2. 3. 4. 5. 6. RESULT: The dimensions of the given component_______________

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Geethanjali College of Engineering and Technology Department of Mechanical Engineering 58 Experiment No. 2 2. INTERNAL MICROMETER Aim: to measure internal diameter of given specimen by using inside micrometer. Instruments used: inside micrometer. Theory: Inside Micrometer is used for measuring larger internal dimensions. It consists of four parts:

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Geethanjali College of Engineering and Technology Department of Mechanical Engineering 59 i Measuring head micrometer unitii Extension rods iii Spacing collars iv Handle. Fig.1. Nomenclature of Internal Micrometer The micrometer unit or measuring head consists of a barrel and a thimble similar to the outside micrometer. It has no frame and spindle. The measuring points are at extreme ends and adjustment is effected by advancing or withdrawing the thimble along the barrel. Extension rods are provided in order to obtain a wide measuring range. The range of measurement for which an extension rod is applicable is always marked on it. Spacing collars are used when those dimensions are needed which can’t be obtained by the use of extension rod micrometer unit. The micrometer set for measuring range 25+ 50mm is generally slipped with a suitable detachable handle so that micrometer head can be easily lowered into deep holes. The micrometer assembly with any combination of extension rods and spacing collars should be very rigid. For taking measurements with this instrument first the diameter of bore is measured approximately by a scale. Extension rod is then selected to the nearest one on and inserted in the micrometer head. Then zero error is checked by tacking the dimension on standard sized specimen like slip gauge Total reading L.S + M.S.R + T.R. x L.C Where:

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Geethanjali College of Engineering and Technology Department of Mechanical Engineering 60 LS Length of sleeve /collar M.S.R. Main scale reading T.R. Thimble reading L.C. Least count S.No. Component to be Measured Diameter M.S.R. Thimble Reading Least Count Total Reading T.R M.S.R + T.R. L.C. 1. 2. 3. 4. RESULT: The dimensions of the given component_______________ Experiment No. 3

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Geethanjali College of Engineering and Technology Department of Mechanical Engineering 61 3. MACHINE TOOL ALIGNMENT TEST ON THE LATHE Alignment tests on the lathe: Test for level of installation or levelling of machine or bed: It is essential that a machine tool be installed in truly horizontal and vertical planes and that this accuracy must be maintained if for example we consider the case of a long bed lathe which is not installed truly horizontal it is clear that the bed will undergo a deflection either to produce a simple bend or if the deflection is in two directions a twist will be introduced. It would thus follow that the movement of the saddle could not be in a straight line and it would therefore be impossible to turn geometric cylinder on the lathe. The maintenance of the initial installation accuracy is depending upon the type and thickness of foundation on which the machine is set. Also this must be insulated from the surroundings floor by introducing some torm or damping. The method of testing for level is shown in Fig. 1. in which is outlined the bed and bed-ways of a centre lathe. Fig:1 With the saddle at the approximate mid-span of the bed support feet a precision level is placed at a-a to give the level in the longitudinal direction. The transverse test at b-b will usually require the use of a bridge piece to span the front and rear guide-ways. Preferably readings should be taken simultaneously in each direction so that the effect of adjustments in one direction may also be observed on the level in the other. It will be noted that readings taken transversely will reveal any twist or wind in the bed. That is. if the bed is out of level readings of the bubble position should all the either plus or minus. The process of correcting the error in level may be clone by wedges and shims set at suitable points under the support feet or pads of the machine until an accuracy of 0.02 mm/meter is obtained. The type of level suitable for this work has a sensitivity of 0.04 mm/meter and has a vee base so that direct contact may be made with the inverted vee ways of the machine bed.

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Geethanjali College of Engineering and Technology Department of Mechanical Engineering 62 The straightness of bed in longitudinal direction for the long beds can also be determined by other methods e.g. using straight edges auto collimators or by taut wire method. But the test in transverse direction can be carried out only by spirit level. True running of locating cylinder of main spindle: To locate the chuck or face plate locating cylinder is used locating surface is cylindrical but not threaded one. Because when threads get worn-out. It causes play in face plate or chuck. For the true run off face plate. It is essential that. Locating cylinder must run truly. Fig: 2 The dial indicator is fixed to the carnage or any other fixed member and the feeler of the indicator touches the locating surface. The surface is then rotated on its axis and indicator should not show any movement of needle. Axial slip of main spindle and true running of shoulder face of spindle nose : Axial play is a normal feature of a thrust bearing and had no effect on true axial running as long as the thrust load is applied consistently in one direction. There will be rise in temperature and as a result thermal expansion of spindle occurs due to its running. If no axial play is allowed it would try to bend. Thus there will be no adverse effect of axial play if the direction of cutting forces remains same. If the direction of cutting force changes there would be some error introduced due to movement of spindle axially in either direction. Under such conditions therefore it is advisable to cut threads in one direction only. Axial slip is defined as the axial spindle movement which follows the same pattern and is due to the manufacturing error. Axial float or slip is due to : i. Errors in the thrust bearing lack of alignment of the thrust washers ii. Lack of alignment of locating shoulder i.e. the face of locating shoulder is not perpendicular to the axis of rotation iii. the face is irregular.

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Geethanjali College of Engineering and Technology Department of Mechanical Engineering 63 Fig: 3 These errors cause an undesirable axial oscillating movement of the spindle during rotation. Plane surfaces and shoulders cannot be obtained with facing operations if the spindle floats axially. For the test after the plunger is placed against the shoulder face of the spindle readings are taken while the spindle axially loaded against the thrust bearings is slowly rotated. Measurements reported with I the dial gauge plunger resting against the shoulder face at a point diametrically opposite to that of the first measurement. In all tests concerning running conditions and alignment of main spindle the machine must be at its working temperature. Due to axial slip in screw cutting the pitch will not be uniform due to periodic movement of the spindle. This however is not important while turning. True Running of Headstock center: If the axis of headstock center is not concentric with the main spindle axis eccentricity will be caused while turning a work. Fig: 4 For testing this error the feeler of the dial indicator is pressed perpendicular to the taper surface of the center Fig. 4 and the spindle is rotated. The deviation indicated by the dial gauge gives the trueness of the center. Parallelism of the main spindle to saddle movement: To be checked in both horizontal vertical directions. The mandrel which is used for this test must so proportioned that its overhang does not produce appreciable sag or else the sag must be calculated and accounted for. A tapered surface is generated when the axis of the spindle is not parallel to bed in horizontal direction. Similarly a hyperboloid surface is generated when the spindle axis is not parallel to bed in vertical direction. For this test a

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Geethanjali College of Engineering and Technology Department of Mechanical Engineering 64 mandrel having a concentric taper shank which closely fits into the spindle not taper is used. It is then fitted in the taper socket of the spindle. Fig: 5 The feeler of the dial indicator is pressed on the mandrel and the carriage is moved. The indication in horizontal plane is given by dial b and in vertical plane by dial ci Fig. 5. In vertical plane the mandrel should be rising towards the free end in order to counteract the weight of mandrel and job. But for counteracting cutting forces it should be lower towards free end. In horizontal plane mandrel should be inclined in a direction opposite to the direction of tool pressure. True Running of taper socket in main spindle : An eccentric and tapered jobs will be produced. When the axis of tapered hole of the socket is not concentric with the main spindle axis. To test a mandrel is fitted into the tapered hole and readings at two extremes of mandrel are taken by I means of a dial indicator as shown in Fig. 6. Fig: 6 Parallelism of tailstock guide ways with the movement of carriage: For turning of the job which is held between head stock and tail stock center the job axis must I coincide with the tail stock center which otherwise results in taper turning.

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Geethanjali College of Engineering and Technology Department of Mechanical Engineering 65 Fig: 7 To check the parallelism of tailstock guide ways in both planes /.e. horizontal and vertical a block is I placed on the guide ways and the feeler of the indicator is touched on the horizontal and vertical surfaces of I the block. The dial indicator is held in the carnage and carriage is moved. Any error is indicated by the pointer of dial indicator. Movement of upper side parallel with main spindle invertical Plane: A mandrel is fitted in the spindle and the dial indicator is fitted in the tool post. Fig: 8 The feeler of the dial gauge is pressed against the mandrel in vertical plane and the upper slide is moved longitudinally. This error is not tested in horizontal plane because there is swiveling arrangement for I taper turning. Parallelism of tailstock sleeve to the saddle movement : The height of dead center would vary as varying lengths of sleeve are taken out. when the tailstock sleeve is not parallel to the saddle movement. It is essential that the central axis of the dead center should be coaxial with the job axis in both the planes when the jobs are held between 2 centers. For this test the dial indicator is fixed on the tool post and the plunger is pressed against the sleeves first in vertical and then in horizontal plane. The carriage is moved along the full length of the sleeve and deviations as indicated by dial indicator are noted down. Tailstock sleeve should be rising towards the free end in vertical plane and should be inclined towards the tool pressure in horizontal plane.

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Geethanjali College of Engineering and Technology Department of Mechanical Engineering 66 Fig: 9 Parallelism of tailstock sleeve taper socket to saddle movement: A mandrel is put in the sleeve socket. The dial gauge is fixed on the tool post and plunger is pressed against the mandrel and saddle is moved from one side to the other. This test is carried out in both the horizontal and vertical planes. Fig: 10 Alignment of both the centers in vertical plane : The axis of the job will not be parallel to the carriage movement when both the main spindle axis tailstock axis may be parallel to carriage movement but they may not be coinciding. This test is to be carried out in vertical plane only. A mandrel is fitted between the two centres and dial gauge on the carriage. The feeler of the dial gauges is pressed

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Geethanjali College of Engineering and Technology Department of Mechanical Engineering 67 Fig: 11 against the mandrel in vertical plane as shown in Fig. 11 and the carriage is moved and the error noted down. Pitch accuracy of lead screw: The accuracy of the threads cut on any machine depends upon the accuracy of its lead screw. Thus it is lead screw. Thus it is very essential thai pitch of the lead screw throughout its length be uniform. Test for this is performed by fixing a positive stop on the lathe bed. Against the stop the length bars and slip gauges can be located. An indicator is mounted on the carriage and first it makes contact against the calculated length of slip gauges. The initial loading of the dial gauge against the slip gauge is noted. The slip gauges are then removed and the carriage is connected to the lead screw and lead screw is disconnected from the gear train. An indexing arrangement is utilized for rotating the lead screw and lead screw is given some revolutions so tha distance travelled by carriage is equal to the length of slip gauges. The reading of the dial indicator against the stop is noted down in this position. If it is same as before there is no error otherwise it can be recorded. Alignment of lead screw bearings with respect to each other: The alignment of the bearings decides the position of the lead screw. Misalignment of lead screw i.e.. it not being parallel to the bed in vertical plane or horizontal plane can cause additional stresses due to bending when carriage is moved. Due to it the lead screw might get damaged and the precision of the machine is reduced. Alignment of lead screw bearings with split nut in both the planes is also essential. Axial slip of lead screw: If both the abutment collar and thrust bearing of the screw are each slightly out of square to the screw axis a periodic pitch error will be introduced into the motion. This error will be additional to any true periodic error existing in the screw itself and may either increase or decrease it. The auto-collimator may be used in conjunction with a reflector mounted on a crossed-strip hinge to detect this error. It may be argued that a dial indicator would be just as applicable to this test since it is this function that the auto-collimator is fulfilling.

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Geethanjali College of Engineering and Technology Department of Mechanical Engineering 68 For testing the axial slip in lead screw a ball is fitted in the end of lead screw and the feeler of the dial gauge is pressed against the ball. The lead screw is rotated and deviation if any. in any direction is noted down. Practical tests: These are of a type designed to reveal the combined effects of several possible errors both in the alignment accuracy of the machine and in its rigidity. They involve the machining of a test piece under prescribed conditions of cutting speed feed rate depth of cut and tool geometry. The test piece is then measured for its geometry and surface finish and the results compared with standards for these features. Experiment No. 4 4.Tool maker’s microscope Aim: To measure the diameters of holes in a given specimen and to measure the distance between the centers of these two holes and also to measure the angle in the specimen. Instrument Used: Tool maker’s microscope Description: Toolmakers microscope and the optical system are shown in Fig..1 A and B.

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Geethanjali College of Engineering and Technology Department of Mechanical Engineering 69 Fig: 1Tool Makers Microscope The optical head tube 1 can be adjusted vertically along the ways of the supporting column 2. The tube is clamped in the required position by the screw 3. The table 5 secured on the base 4 has a compound slide by means of which the measures part can have longitudinal and lateral movements controlled by accurate micrometer screws having thimble scale and vernier 6 and 7. The light source 8 provides a horizontal beam which is reflected by the mirror 9 through 90 0 . The beam of light passes through a transparent glass plate or stage 10 on which flat parts may be placed. A shadow image of the outline or contour of the part passes through the objective 11 of the tube and is projected by a system of three prisms to a ground glass screen 12. Observations are made through the eyepiece 13. Measurements are made by means of cross lines engraved on the ground glass screen. This screen can be rotated through 360" and the angle of rotation is read through the microscope. Various graduated and engraved screens and corresponding eyepieces are used for different measuring elements. A revolving screen is used for measuring standard threads. All basic profiles of threads in the pitch range from 0.25 to 4mm are engraved on the screen. The angle of the thread is determined by rotating the screen until a line on the screw coincides with one flank of the thread profile. A angle of screen rotation is noted and then the screen is rotated further until the same line coincides with the other flank of the thread. The difference in angular reading will be the actual angle of thread on the screw.

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Geethanjali College of Engineering and Technology Department of Mechanical Engineering 70 USE OF TOOL MAKERS MICROSCOPE: The instrument has its greatest utility in measuring odd profiles hole locations and the location of -odd profiles angles etc. especially on their flat stock where conventional methods of measurement are difficult. It is useful for checking jigs. Figure 1. represents an intricate workpiece and the dimensions to be checked down on it. In the field of microscope a small area only is visible. Figure also shows the steps in-obtaining the various dimensions. Checking dimension f: Rotate the job on the table until the edge x is parallel to the horizontal cross hair B clamp the workpiece in this position and the whole table is slid till the edge y coincides with the horizontal cross wire - to check the proper claiming of workpiece. Note the reading of the micrometer when the edge x coincides with horizontal cross hair. Bring any one the holes in to the field view of the microscope by operating thimble screws. The hole is centered on the vertical cross hair and the upper edge is located tangent to the horizontal cross hair C The reading of the micrometer is noted. Again the workplace is-moved until the horizontal cross hair is tangential to the lower edge of the table D and the micrometer reading is noted. Determine the differences of readings BC and B.D. The average of these two readings will give the dimension f. Now the table is moved along horizontally until intersection of edge z with the cross hair E takes place. The right to left micrometer reading is taken. Using the above technique the dimension a can be checked/determined. In a similar way. all the other dimensions can be measured. TYPICAL APPLICATIONS OF TOOL MAKERS MICROSCOPE: 1. Linear measurement: The workpiece is placed over the table. The microscope is focused and one end of the workpiece is made to coincide with the cross line in the microscope by operating micrometer screws. The table again is moved until the other end of the workpiece coincides with the cross line on the screen and final reading taken. The difference between the initial and final reading gives the required linear measurement. 2. Measurement of screw pitch: The screw is mounted on the table. The microscope is focused until a sharp image of the projected contour of the screw is seen on the ground glass screen. The contour is set so that some point on the contour coincides with the cross line on

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Geethanjali College of Engineering and Technology Department of Mechanical Engineering 71 the screen. The reading on the thimble of longitudinal micrometer screw is noted. Then the table is moved by the same screw until a corresponding point profile of the next thread coincides with the cross line. The reading is again noted and the difference in two readings gives the screw pitch. 3. Measurement of thread angle: The screw is rotated until a line on the screen coincides with a flank of the thread and the reading is noted. The screen is further rotated until the same line coincides with the other flank of the thread. The difference between two angular readings gives the angle of the thread. 4. Pitch diameter: Lateral movement to the table is given to measure the pitch diameter of the thread. Various types of graduated and engraved screws and corresponding eye pieces are used for measuring different elements. The main objective lens is interchangeable giving a magnification range X10 X25 X30. X60 and X100. The graticule also is interchangeable to cater for line angular radial and thread form inspection. The tool makers’ microscope although capable of inspecting any component shape that can be accommodated by optical projectors is best suited to relatively small intricate components and tools. Tool signature of the given H.S.S.Single point cutting tool:-

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Geethanjali College of Engineering and Technology Department of Mechanical Engineering 72 Experiment No. 5 5. a. Bevel Protractor AIM : To measure the angle of V-Block and given specimen by using bevel protractor. APPARATUS: Bevel protractor V-Block Specimen and surface plate. SPECIFICATIONS: size of the adjustable blade least count 5 1 THEORY AND DESCRIPTION: It is used to measure the angle between two surfaces to an accuracy of 5 minute. This consists of main body base plate adjustable blade circular plate containing vernier scale and acute angle attachment The base plate in attached to the main body as an adjustable blade is attached to a circular plate containing vernier scale. The main scale graduated in degree is provided on the main body the adjustable blade is capable of rotating fully about the center of main scale engraved on the body of the instrument can be locked in any position. An acute angle is attached is provided at time top for measuring acute angles. The blade can be reversed. It is about 150 - 300 mm per angle 13 mm wide and 2 mm thick. Its ends are beveled at angle of 45° 60°. LEAST COUNT CALCULATION: The main scale is graduated in degree of arc. The vernier scale has 12 divisions each side of center of zero. These are marked 0.60 nun of arc so that each division occupies the same space 23 degree on main scale. Therefore each division on me main scale and 1 division on the vernier scale is 2° 5 1 of arc.

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Geethanjali College of Engineering and Technology Department of Mechanical Engineering 73 PROCEDURE: The base plate of protractor is allowed to coincide with arc side of the angles and on adjustable blade with other side of the angle. At mid position blade is locked by locking nut. The inclined angle between the base plate and adjustable blade is calculated. Fig .1 : Bevel Protractor OBSERVATIONS : M.S.R. Main Scale Reading V.S.R Vernier Scale Reading L.C Least Count Total Reading M.S.R + V.S.R. L.C S.No. Component M.S.R. V.S.R. L.C. Total Reading PRECAUTIONS: 1. The reading should be taken with out any parallax error. RE8ULT: The total included angle for specimen

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Geethanjali College of Engineering and Technology Department of Mechanical Engineering 74 5. b. SINE BAR Aim: To measure the taper angle of a given specimen by using sine bar. Apparatus : Sine Bar slip gauges angle plates dial indicator surface plates. Theory: Sine bars are used either for measuring angles very accurately or for locating any work to a given angle within very close limits. For precision work the upper face of the since bar must be parallel with the plane passing through the axes of both cylinders. The top and bottom faces of the sine bar also must be parallel so that the top or bottom face could be used as working surfaces. Some holes are drilled in the sine bar to reduce the weight and also for easy handling. The distance l between the axes of the cylinders is exactly 10000 300mm in metric system. Fig: 1. Sine Bar Principle of sine bar: The principle of operation of sine bar is based on the laws of trigonometry. To set a given angle on e roller of the bar is placed on the surface plate and the combination of slip gauges is inserted under second roller. Sin bars is conjunction with slip gauges constitute a very good device for the precise measurement of angles. The arrangement is based on the fact that for any particular angle ‘ the sides of a right angle triangle will have precise ratios i.e.

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Geethanjali College of Engineering and Technology Department of Mechanical Engineering 75 Fig.2: Sine Principle Sin Opposite side / Hypotenuse h / l If h and l could be measured accurately value ‘h’ is built by slip gauges and the value ‘l’ is constant for a given sine bar. Procedure: For measuring an unknown angle a set up similar to one shown in fig 3 is made use of with the help of angle plate clamping the sine bar to an approximate value of the angle of the job. A dial indicator is moved on the surface of the job after locating the job on the surface of the sine bar. The slips are adjusted so that the dial indicator reads zero when moved across the work surface. Fig.3:Angle measurement set up of taper plug gauge

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Geethanjali College of Engineering and Technology Department of Mechanical Engineering 76 Thus the angle of the job is obtained by sin -1 h l For better results both the rollers could be placed on slip gauges of height h and h 2 respectively. Then Sin h 2 -h 1 l where: h 1 Height of the slip gauges under the first roller h 2 Height of the slip gauges under the second roller l center distance between the roller of the sine bar Note 1: Sine bar is fairly reliable for angles less than 15 o and becomes increasingly inaccurate as the angle increases. It is impractical to use sine bars for angle above 45 o Note 2: For larger work the sine bare principle can be extended by making equipment in the form of sine centers. Precautions : 1.Reading should be taken without any parallax error. Questions : 1.What are the limitations of sine bar 2.What is sine center

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Geethanjali College of Engineering and Technology Department of Mechanical Engineering 77 Experiment No. 6 6. Surface roughness measurement by Talysurf Aim: To measure the surface roughness of the given specimen by using Talysurf. Equipment: Taylor – Hobson Talysurf C.I. block.

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Geethanjali College of Engineering and Technology Department of Mechanical Engineering 78 Theory: Taylor – Hobson Talysurf is a stylus and skid type of instrument working on carrier modulating principle. The measuring head of this instrument consists of a sharply pointed diamond stylus of about 0.002 mm tip radius and skid or shoe which is drawn across the surface by means of a motorised driving unit. Fig: 1. Taylor – Hobson Talysurf In this instrument the stylus is made to trace the profile of the surface irregularities and the oscillatory movement of the stylus is converted into changes in electric current by the arrangement as shown in fig 1. The arm carrying the stylus forms an armature which pivots about the centerpiece of E – Shaped stamping. On two legs of Outer Pole Pieces the E – Shaped stamping there are coils carrying an A.C. currant. These two coils with other two resistances form an oscillator. As the armature is pivoted about the central leg any movement of the stylus causes the air gap to vary and thus the amplitude of the original a.c. current flowing in the coils is modulated. The output of the bridge thus consists of modulation only as shown in figure this is further demodulated so that the current now is directly proportional to the vertical displacement of the stylus only. The demodulated output is caused to operate a pen recorder to produce a permanent record and the meter to give a numerical assessment directly. If it is a graph for assessment of average roughness the following three methods are used:- 1 C.L.A Method Ra 2 R.M.S. Method Ra 3 Ten Point Height Method Rz

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Geethanjali College of Engineering and Technology Department of Mechanical Engineering 79 C.L.A Value measured is preferred to R.M.S Value measure because its value can be easily determined by measuring the areas with planimeter or graphs or can be readily determined in electrical instruments by integrating the movement of the stylus and displaying the result as an average. Centerline Average or Arithmetic Average is defined as the average values of the ordinates from the mean line regardless of arithmetic sings of the ordinates. Ra or C.L.A. Value h 1 +h 2 +h 3 +…. h n microns N Where: h 1 +h 2 +h 3 +…. h n Average heights above ad below the mean line regardless of the arithmetic signs of the ordinates N No. of average heights Case i: The C.L.A value can also be calculated by using the Planimeter. Ra or C.L.A A 1 +A 2 +A 3 +…. A n A microns L L Where : L sampling length A Area of planimeter C.L.A. method: In this method the surface roughness is measured as the average deviation from the nominal surface. For the purpose of quantitative comparisons and analysis it is necessary to express the roughness of surface in terms of an index. Figi shows the cross- section under consideration. A mean line ML is found that is parallel to the general surface direction and divides the surface in such a way that the sun of the areas above the ML is equal to the sum of the areas below the ML. The - x-axis is drawn parallel to the general surface direction and touches the lowest trough of the surface. A minimum base light i.e. sampling length ‘L’ must be chosen to make the measurement reliable and typical of the whole surface. Case ii C.L.A Scale Horisontal X ale VerticalSc X A A 1 1 Procedures:

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Geethanjali College of Engineering and Technology Department of Mechanical Engineering 80 1 Place the given specimen on the table and then adjust the stylus to touch the surface of the specimen. 2 By taking appropriate sampling length. The profile of the surface is drawn by using Talysurf. 3 Average roughness can be assessed from the graph by using C.L.A. method. Questions: 1 What is primary texture 2 What is secondary texture 3 In many cases the sampling length is not specified Should be the assumed sampling length in these cases 4 What is lay 5 What is the difference between R a and R z values 6 What is the international parameter of roughness and how it is measured

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