LATHE



EXPERIMENT 1

INTRODUCTION TO GENERAL PURPOSE MACHINES –LATHE, DRILLING, MILLING AND SHAPER (STUDY)

1. LATHE

1.1 INTRODUCTION

The lathe is one of the oldest machine tools. The main function of a lathe is to remove metal from a piece of work to give it the required shape and size. This accomplished by holding the work securely and rigidly on the machine and then turning it against cutting tool, which will remove, metal from the work in the form of chips. To cut the material properly the tool should be harder than the material of the work piece, should be rigidly held on the machine and should be fed or progressed in a definite way relative to the work.

1.2 MAIN PARTS OF A LATHE

 Bed: Usually made of cast iron. Provides a heavy rigid frame on which all the main components are mounted.

Guide ways: Inner and outer guide rails that are precision machined parallel to assure accuracy of movement.

Headstock : mounted in a fixed position on the inner ways, usually at the left end. Using a chuck, it rotates the work.

Gearbox: inside the headstock, providing multiple speeds with a geometric ratio by moving levers.

Spindle: Hole through the headstock to which bar stock can be fed, which allows shafts that are up to 2 times the

length between lathe centers to be worked on one end at a time.

Chuck: 3-jaw (self centering) or 4-jaw (independent) to clamp part being machined.

Tailstock: Fits on the inner ways of the bed and can slide towards any position the headstock to fit the length of

the work piece. An optional taper turning attachment would be mounted to it. 

Tailstock Quill: Has a Morse taper to hold a lathe center, drill bit or other tool.

Carriage: Moves on the outer ways. Used for mounting and moving most the cutting tools.

Cross Slide: Mounted on the traverse slide of the carriage, and uses a handwheel to feed tools into the workpiece.

Tool Post: To mount tool holders in which the cutting bits are clamped.

Compound Rest: Mounted to the cross slide, it pivots around the tool post.

Apron: Attached to the front of the carriage, it has the mechanism and controls for moving the carriage and cross

slide.

Feed Rod: Has a keyway, with two reversing pinion gears, either of which can be meshed with the mating bevel

Ear to forward or reverse the carriage using a clutch.

Lead Screw: For cutting threads.

Split Nut: When closed around the lead screw, the carriage is driven along by direct drive without using a clutch.

Quick Change Gearbox: Controls the movement of the carriage using levers. 

1.3 SPECIFICATIONS

The size of a lathe is expressed or specified by the following items and illustrated in the given figure no.2.

1. The height of the centers measured from the lathe bed.

2. The swing diameter over bed. This is the largest diameter of work that will revolve without touching the bed and is twice the height of the center measured from the bed of the lathe.

3. The length between centers. This is the maximum length of work that can be mounted between the lathe centers.

4. The swing diameter over carriage. This is the largest diameter of work that will revolve over the lathe saddle, and is always less than the swing diameter over bed.

5. The maximum bar diameter. This is the maximum diameter of bar stock that will pass through the hole of the headstock spindle.

6. The length of bed. This indicates the approximate floor space occupied by the lathe.

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Block Diagram of Lathe

2. DRILLING MACHINE

2.1 INTRODUCTION

The drilling machine is one of the most important machine tools in a workshop. As regards its importance it is second only to the lathe. The hole is generated by the rotating edge of a cutting tool known as the drill, which exerts a large force of the work clamped on the table. As the machine tool exerts vertical pressure to originate a hole it is loosely called a “drill press”.

2.2 MAIN PARTS OF A RADIAL DRILLING MACHINE

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BLOCK DIAGRAM OF DRILLING MACHINE

1. Head: Head contains the electric motor, v pulleys and v belt , which transmit rotary motion to the drill spindle at a no. of speeds.

2. Spindle: spindle is made up of alloy steel. It rotates as well as move up and down in a sleeve.

3. Drill chuck: It is held at the end of the drill spindle and in turn it holds the drill bit.

4. Adjustable table: It is supported on the column of the drilling machine and can be moved vertically and horizontally. It also carries slots for bolts clamping.

5. Base: It supports the column, which, in turn, supports the table, head etc.

6. Column: It is a vertical round or box section, which rests on the base and supports the head and the table.

2.3 SPECIFICATIONS

The size of a drilling machine varies with the type of machine being considered.

1. A portable drilling machine is specified by the maximum diameter of the drill that it can hold.

2. The sensitive and upright drilling machines are specified by the diameter of the largest piece that can be centered under the spindle. Thus, in the case of a 600 mm size upright drilling machine, the spindle placed at a distance is slightly greater than 300 mm from the front face of the column.

3. To specify a drilling machine , fully further particulars such as the maximum size of drill that the machine can operate, table diameter, the maximum spindle travel, numbers of spindle speeds and feeds available, the Morse taper number of the drill spindle, power input floor space required, net weight of the machine etc. are all needed.

4. The size of a radial drilling machine is specified by the diameter of the column and the length of the arm. Other particulars such as maximum drilling radius, minimum drilling radius, spindle speeds and feeds, etc. should also be stated to specify the machine fully.

3. MILLING MACHINES

3.1 INTRODUCTION A milling machine is a machine tool that removes metal as the work fed against a rotating multipoint cutter. The cutter rotates at a high speed and because of the multiple cutting edges it removes metal at a very fast rate. The machine can also hold one or more cutters at a time. This is a why a milling machine finds wide application 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.

3.2 MAIN PARTS OF A MILLING MACHINE

 1. Base: It gives support and rigidity to the machine and also acts as a reservoir for the cutting fluids.

2. 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 table feed.

3. Knee: The knee is a rigid casting mounted on the front face of the column. The knee moves vertically along the guide ways and this movement enables to adjust the distance between the cutter and the job mounted on the table. The adjustment is obtained manually or automatically by operating the elevating screw provided below the knee.

4. Saddle: The saddle rests on the knee and constitutes the intermediate part between the knee and the table. The saddle moves transversely, i.e., crosswise (in or out) on guide ways provided on the knee.

5. Table: The table rests on guide ways in the saddle and provides support for the work. The table is made of cast iron, its top surface is accurately machined and carriers T-slots which accommodate the clamping bolt for fixing the work. The worktable and hence the job fitted on it is given motions in three directions:

a). Vertical (up and down) movement provided by raising or lowering the knee.

b). Cross (in or out) or transverse motion provided by moving the saddle in relation to the knee.

c). Longitudinal (back and forth) motion provided by hand wheel fitted on the side of a feed screw.

In addition to the above motions, the table of a universal milling machine can be swiveled 45° to either side of the center line and thus fed at an angle to the spindle.

6. Overarm: The Overarm is mounted at the top of the column and is guided in perfect alignment by the machined surfaces. The Overarm is the support for the arbor.

7. Arbor support: The arbor support is fitted to the Overarm and can be clamped at any location on the Overarm. Its function is to align and support various arbors. The arbor is a machined shaft that holds and drives the cutters.

8. Elevating screw: The upward and downward movement of the knee and the table is given by the elevating screw that is operated by hand or an automatic feed.

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HORIZONTAL MILLING MACHINE

4. SHAPER

A shaper is a type of machine tool that uses linear relative motion between the work piece and a single-point cutting tool to machine a linear tool path. Its cut is analogous to that of a lathe, except that it is linear instead of helical. (Adding axes of motion can yield helical tool paths, as also done in helical planning.) A shaper is analogous to a planner, but smaller, and with the cutter riding a ram that moves above a stationary work piece, rather than the entire work piece moving beneath the cutter. The ram is moved back and forth typically by a crank inside the column; hydraulically actuated shapers also exist. A shaper is a type of machine tool that uses linear relative motion between the work piece and a single-point cutting tool to machine a linear tool path. Its cut is analogous to that of a lathe, except that it is linear instead of helical. (Adding axes of motion can yield helical tool paths, as also done in helical planning.) A shaper is analogous to a planner, but smaller, and with the cutter riding a ram that moves above a stationary work piece, rather than the entire work piece moving beneath the cutter. The ram is moved back and forth typically by a crank inside the column; hydraulically actuated shapers also exist.

4.1 PRINCIPAL PARTS OF A SHAPER

1. BASE: It is a heavy and robust cast iron body which as a support for all the other parts of the machine which are mounted over it.

2. COLUMN: It is a box type cast-iron body mounted on the base acts as housing for the operating mechanism of the machine and electrical. It also acts as a support for other parts of the machine such as cross rail and ram.

3. CROS RAIL: It is a heavy cast iron construction attached to the column at its front on the vertical guide ways. It carries two mechanisms: one for elevating the table and the other for the cross traversing of the table.

4. TABLE: It is made of cast iron and has a box type construction. It holds and supports the work during the operation and slides along the cross rail to provide fed to the work.

5. RAM: It is also an iron casting, semicircular in shape and provides with a ribbed construction inside for rigidity and strength. It carries the tool head and travels in dovetail guide ways to provide a straight line motion to the tool.

6. TOOL HEAD: It is a device in which is held the tool. It can slide up and down can be swung to a desired angle to set the table desired position for the operation.

7. VICE: It is job holding device and is mounted on the table. It holds and supports the work during the operation.

4.2. WORKING PRINCIPLE

In case of shaper; the job is rigidly held in a suitable device like a vice or clamped directly 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 material in the forward stroke. No cutting of material takes place during the return stroke of the ram. Hence it is termed as idle stroke. However in case of a draw cut shaper the cutting takes place in the return stroke and the forward stroke is an idle stroke. The job is given an index fed in a direction normal to the line of action of the cutting tool.

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BLOCK DIAGRAM OF SHAPER

EXPERIMENT 2

PLANNING , SLOTTING , CYLINDRICAL GRINDING, SURFACE GRINDING AND TOOL AND CUTTER GRINDING MACHINE (STUDY)

1. PLANING MACHINES

1.1 .INTRODUCTION

The planer like a shaper is a machine tool primarily intended to produce a plane and flat surfaces by a single point cutting tool. A planer is very large and massive compared to shaper and capable of machining a heavy work piece which cannot be accommodated on a shaper table. The fundamental difference between a shaper and a planer is that in a planer the work which is supported on the table reciprocates past the stationary cutting tool and the feed is supplied by the lateral movement of the tool, whereas in a shaper the tool which is mounted upon the ram reciprocates and the feed is given by the crosswise movement of the table.

1.2. PLANING MACHINE PARTS

Bed and table: The bed is a long , heavy base and table made of cast iron. Its top surface is flat and machined accuratelly. The flat top surface has slots in which the workpiece can be securely clamped. The workpiece needs rigid fixing so that it does not shift out of its position. The standard clamping devices used on planer machine are: Heavy duty vice, T-holders and clamps, angle plate, planer jack, step blocks and stop. The table movement may be actuated by a variable speed drive through a rack and pinion arrangement, or a hydraulic system.

Housings: The housings are the rigid and upright column like castings. These are located near the center on each side of the base.

Cross rail: The cross rail is a horizontal member supported on the machined ways of the upright columns. Guide ways are provided on vertical face of each column and that enables up and vertical movement of the cross rail. The vertical movement of the cross rail allows to accommodate workpiece of different heights. Since the cross rail is supported at both the ends, this type of planer machine is rigid in construction.

Tool heads: Generally two tool heads are mounted in the horizontal cross rail and one on each of the vertical housing. Tool heads may be swiveled so that angular cuts can be made.

Driving and feed mechanism: The tool heads may be fed either by hand or by power in the crosswise or vertical direction. The motor drive is usually at one side of the planer near the center and drive mechanism is located under the table.

The size of the planner is specified by the maximum length of the stroke, and also by the size of the largest rectangular solid that can be machined on it.

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BLOCK DIAGRAM OF PLANER

1.3. OPERATIONS OF PLANER MACHINE:

1. Planing flat horizontal, vertical and curved surfaces.

2. Planning at an angle and machining dovetails.

3. Planning slots and grooves.

SLOTTING MACHINES

2.1 INTRODUCTION

The slotting machine falls under the category of the reciprocating type of machine tool similar to a shaper or a planer. It operates almost on the same principle as that 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, whereas in a shaper the ram holding the tool reciprocates in a horizontal axis. A vertical shaper and a slotter are almost similar to each other as regards to their construction, operation, and use. The only difference being, in the case of a vertical shaper, the ram holding the tool may also reciprocate at an angle to the horizontal table in addition to the vertical stroke. The ram can be swiveled not more than 5° to the vertical. The slotter is used for cutting grooves, keyways and slots of various shapes, for making regular and irregular surface both internal and external, for handling large and awkward work pieces, for cutting internal or external gears and many other operations which cannot be conveniently machined in any other machine tool.

2.2 MAIN PARTS OF A SLOTTING MACHINE

COLUMN: The Column consists of two parts which are adequately ribbed & securely held together to form a rigid unit. The deep throat enables a wide variety of parts to be machined.

DRIVE  The Electric motor drives the clutch pulley and the gears fitted in the column. From there the power is transmitted to the ram by the means of link mechanism. The ram-movement is started by engaging the clutch. The link mechanism allows for an accelerated ram-movement in return stroke Ram speed changes are effected by sliding gears controlled by shaft through gear box.

RAM: The ram is well ribbed and is quite strudy. An taper wedge is provided for smooth running. The ram can be tilted 5 degrees on demand and swiveled 10 degrees in case of 400 mm stroke.

TABLE : The table is circular and is provided with T-slots. It is divided on its circumference into 360 degrees. A tapered whole is provided in the center of the table for reception of the centering mandrel while machining circular slotting work. Direct Indexing is provided for accurately locating the various positions.

FEED: The feed mechanism mounted on the column through side gearbox. The feeds are infinitely within range of 0.2mm to 1.5mm for 150 mm, 250mm & 300 mm. In case of 450mm stroke 0.2mm to 2 mm per cycle. The feeds can be adjusted when the machine is at the rest.

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MAIN PARTS OF A SLOTTER.

3. CYLINDRICALGRINDING MACHINES

3.1. INTRODUCTION

This machine is used to produce an external cylindrical surface. The surfaces may be straight, tapered, steps or profiled. Broadly, there are three different types of cylindrical grinding machine as follows:

1. Plain center type cylindrical grinder

2. Universal cylindrical surface grinder

3. Centrerless cylindrical surface grinder

Plain center type cylindrical grinder

The machine is similar to a center lathe in many respects. The workpiece is held between headstock and tailstock centers. A disc type grinding wheel performs the grinding action with its peripheral surface. Both traverse and plunge grinding can be carried out on this machine .

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4 SURFACE GRINDING MACHINE:

4.1. INTRODUCTION

This machine may be similar to a milling machine used mainly to grind flat surface. However, some types of surface grinders are also capable of producing a contour surface with formed grinding wheel.

Basically there are four different types of surface grinding machines characterized by the movement of their tables and the orientation of grinding wheel spindles as follows:

1. Horizontal spindle and reciprocating table

2. Vertical spindle and reciprocating table

3. Horizontal spindle and rotary table

4. Vertical spindle and rotary table

Horizontal spindle reciprocating table grinder

This machine with various motions required for grinding action. A disc type grinding wheel performs the grinding action with its peripheral surface. Both traverse and plunge grinding can be carried out in this machine .

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Vertical spindle reciprocating table grinder

This grinding machine with all working motions is shown in following figure. The grinding operation is similar to that of face milling on a vertical milling machine. In this machine a cup shaped wheel grinds the workpiece over its full width using the end face of the wheel. This brings more grits in action at the same time and consequently a higher material removal rate may be attained than for grinding with a peripheral wheel.

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Horizontal spindle rotary table grinder

In principle the operation is same as that for facing on the lathe. This machine has a limitation in accommodation of workpiece and therefore does not have widespread use. However, by swivelling the worktable, concave or convex or tapered surface can be produced on individual part as illustrated in Fig. 29.6

Vertical spindle rotary table grinder

The machine is mostly suitable for small workpieces in large quantities. This primarily production type machine often uses two or more grinding heads, thus enabling both roughing and finishing in one rotation of the work table.

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5. TOOL AND CUTTER GRINDER:

Tool and Cuter grinders are used mainly to sharpen and recondition multiple tooth cutters like reamers, milling cutters, drills, taps, hobs and other types of tools used in the shop. With various attachments they can also do light surface, cylindrical, and internal grinding to finish such items as a jig, fixture, die and gauge details and sharpen single point tools. They are classified, according to the purpose of grinding into two groups: Universal – tool and cuter grinders Single – purpose tool and cuter grinders

Universal toot and cutter grinders are particularly intended for sharpening of miscellaneous cutters. Single purpose grinders are used for grinding tools such as drill, tool-bits, etc, in large production plants where large amount of grinding work is necessary to keep production tools in proper cutting condition. In addition tools can be ground uniformly and with accurate cutting angles.

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EXPERIMENT 3

STEP TURNING AND TAPER TURNING ON LATHE

1. AIM: To perform Step turning and Taper turning operations on the given work piece

2. MATERIAL REQUIRED: Mild steel rod of 25 mm diameter and 10 mm long.

3. TOOLS REQUIRED: Vernier calipers, steel rule, spanner, chuck spanner, and H.S.S. Single point

Cutting tool.

4. MACHINE REQUIRED: Lathe

5. THEORY: Lathe removes undesired material from a rotating workpiece in the form of chips with the help of a tool which is traversed across the work and can be fed deep in work. The tool material should be harder than the work piece and the Later help securely and rigidly on the machine. The tool may be given linear motion in any direction. A lathe is used principally to produce cylindrical surfaces and plane surfaces, at right angles to the axis of rotation. It can also produce tapers and below etc.

6. SEQUENCE OF OPERATIONS:

1 .Centering

2. Facing

3. Plain turning

4. Chamfering

5. Step turning

6. Grooving

7. Taper turning

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1. The work piece is fixed in a 3-jaw chuck with sufficient overhang.

2. Adjust he machine to run the job to a required cutting speed.

3. Fix the cutting tool in the tool post and centering operation is performed so give the feed and depth of cut of the cutting tool

4. Facing operation is performed from the center of the job towards outwards or from the circumference towards the center.

5. Plain turning operation is performed until the diameter of the work piece is reduced to 23 mm.

6. Check the dimensions by using vernier calipers.

7. Then chamfering is done on the 23mm diameter surface.

8. Reverse the workpiece in the chuck and facing operation is performed to reduce the length of work piece to the required dimensions.

9. Again the Plain turning operation is performed until the diameter of the work piece reduced to 18mm.

10 .Using V-cutting tool grooving operation is performed according to the given dimensions and finish the grove using a parting tool.

11. Swivel the compound slide to the required angle and taper turning operation by rotating the compound slide wheel.

The angle can be measured by using the formula

D-d

Tanα =-----------------

2L

12. Check Finally the dimensions by using vernier calipers.

PRECAUTIONS:

1. The workpiece should be held rigidly in the chuck before operating the machine.

2. Tool should be properly ground, fixed at correct height and properly secured, and work also be firmly secured.

3. Before operating the machine see whether the job and tool is firmly secured in devices or not.

4. Optimum machining conditions should be maintained.

5. Chips should not be allowed to wound around a revolving job and cleared as often as possible

6. Apply cutting fluids to the tool and work piece properly.

RESULT: Job had done according to given figure.

EXPERIMENT 4

THREAD CUTTING AND KNURLING ON LATHE

AIM: To perform Thread cutting and Knurling operation on the given work piece.

MATERIAL REQUIRED: Mild Steel rod of 25 mm diameter and 10 mm long

TOOLS REQUIRED: vernier calipers, steel rule, spanner, chuck spanner, and H.S.S. Single point

cutting tool, parting tool and V- cutting tool.

THEORY: Lathe removes undesired material from a rotating workpiece in the form of chips with the help of a tool which is traversed across the work and can be fed deep in work. The tool material should be harder than the work piece and the later help securely and rigidly on the machine. The tool may be given linear motion in any direction. A lathe is used principally to produce cylindrical surfaces and plane surfaces, at right angles to the axis of rotation. It can also produce tapers and bellows etc. A lathe basically consists of a bed to provide support, a headstock, a cross side to traverse the tool, a tool post mounted on the cross slide. The spindle is driven by a motor through a gearbox 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 lead screw are also provided to power the carriage and for cutting the threads respectively.

SEQUENCE OF OPERATIONS:

Centering

Facing

Plain turning

Chamfering

Step turning

Grooving

Thread cutting

Knurling

PROCEDURE:

1. The work piece is fixed in a 3 – jaw chuck with sufficient overhang.

2. Adjust the machine to run the job to required cutting speed.

3. Fix the cutting tool in the tool post and centering operation is performed so that the axis of the job coincides with the lathe axis.

4. The Facing is performed by giving longitudinal depth of cut and cross feed.

5. Perform plain turning operation until the diameter of the work piece reduced to 20mm.

6. Chamfering operation is done according to the given dimensions.

7. Then reverse the workpiece in the chuck and plain turning operation is performed according to the given dimensions.

8. Using V-cutting tool and parting off tool perform grooving operation to the required dimensions.

9. Reduce speed of the spindle by engaging back gear and use Tumbler feed reversing mechanism to transmit power through the lead screw and calculate the change gears for the required pitch to be made on the work piece.

10. Using half nut mechanism perform thread cutting operation(right hand threading) according to the given dimensions and continues it until required depth of cut is obtained.

11. At the same speed knurling operation is performed using knurling tool.

12. For every operation check the dimensions using vernier calipers.

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PRECAUTIONS:

1. Low spindle speeds should be used for accurate threads in thread cutting operation.

2. Ensure correct, engage and dis-engage of half- nut.

3. Plenty of oil should be flown on the work and tool during thread cutting.

RESULT: Job had done according to given figure

EXPERIMENT 5

DRILLING AND TAPPING

1. AIM: To drill the given work piece as required and then to perform internal threading operations on the given specimen.

2. MATERIALS REQUIRED: mild steel specimen, coolant (oil and water mixture), lubricant oil, nut and bolt.

3. MACHINE REQUIRED: Drilling machine

4. MEASURING INSTRUMENTS: Vernier calipers

5. CUTTING TOOLS: Button pattern stock, Dies, Drill bids, Hand taps and Tap wrench.

6. MARKING TOOLS: Dot punch

7. WORK HOLDING FIXTURES:Bench vice, V-Block

8. MISCELLANEOUS TOOLS: Brush,Allen Keys

9. SEQUENCE OF OPERATIONS:

a. Mark the center of hole and center punching

b. Drill bid

Dd = dh-p Where,

Dh - dia. of the hole,

dd – dia. of drill bid,

p = pitch

c. Use the suitable drill size for required tapping

D=Dia. of tap Tap Drill size = (D-1.3p)+0.2 – for metric threads

d. Chamfering of specimen

e. Use the sequential tapping as tap set 1,2,3

f. Internal taping of drilled specimen

g. Filling of specimen on which external threading to be done

h. Measuring the diameter of the specimen & choosing of dies according to it

PRECAUTIONS:

1. Ensure that the edges of the flat are perfectly square.

2. Slightly lower speeds of the order of 25% less than drilling should be used in reaming operation,

3. Drilling should be performed only after pilot hole is made.

RESULT: Required specimen obtained according to specified operations(drilling and tapping operations) with given dimensions

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EXPERIMENT 6

SHAPING AND PLANNING

SHAPING

1. AIM: To perform V -cut on the given work piece.

2. MATERIALS REQUIRED: Mild steel / Cast iron / Cast Aluminum.

3. MACHINE REQUIRED: Shaping machine

4. MEASURING INSTRUMENTS: Vernier calipers, Vernier height gauge, Dial indicator, Required steel bar.

5. CUTTING TOOLS : H.S.S tool bit, V tool, Plain tool.

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6. SEQUENCE OF OPERATIONS:

1. Measuring of specimen.

2. Fixing of specimen in the machine vice of the shaping machine

3. Giving the correct depth and automatic feed for the slot is to be made.

4. Check the slot with the Vernier calipers & precision measurement by slip gauges at the end.

7. PROCEDURE:

1. The two ends of the work piece are first smoothed by filing and apply chalk on its surface.

2. Place the work piece in the V-block and mark center on the end face using surface gauge, scriber and Vernier

height gauge.

3. Mark square on the end face , according to the required dimensions.

4. By using dot punch made permanent indentation marks on the work piece.

5. The tool is fixed to the tool post such that the tool movement should be exactly perpendicular to the table.

6. The workpiece is then set in the vice such that the tool is just above the work piece.

7. Adjust the length of the stroke.

8. Make sure that line of action of the stroke should be parallel to the surface of the work piece.

9. Give depth of cut by moving the tool and feed is given to the workpiece during the return stroke of the ram.

10. Continue the process, until the required dimensions are to be obtained.

11. Repeat the process for all the four sides.

12. Finally , make a key way on one side, according to the given dimensions

8. PRECAUTIONS:

1. Marking should be done accurately.

2. The workpiece should be set securely and rigidly in the vice.

3. Before starting a shaper make sure that the work vise, tool, and the ram is securely fastened.

4. Check that the tool and tool holder will clear the work and also the column on the return stroke.

5. Always stand parallel to the cutting stroke and not in front of it.

6. Never attempt to remove chips or reach across the table while the ram is in motion.

7. Never attempt to adjust a machine while it is in rotation.

8. Suitable feeds and depth of cut should be maintained uniformly.

9. Apply cutting fluids to the tool and work piece properly.

10. Always feed will be given to the tool in the backward stroke only.

9. RESULTS: Required specimen obtained according to specified operation with given dimensions

PLANNING

1. AIM: To perform plane planning operation on the given specimen (mild steel) & get to its correct dimensions.

2. MATERIALS REQUIRED: Mild steel specimen.

3. MACHINE REQUIRED: Planning machine

4. MEASURING INSTRUMENTS: Vernier calipers

5. CUTTING TOOLS: Single Point cutting tool

6. MARKING TOOLS: Steel rule, scriber, Work holding fixtures: work piece supporting fixtures

7. SEQUENCE OF OPERATIONS:

1. Measuring of specimen

2. Fixing of specimen in the vise on the planning machine.

3. Giving the correct depth and automatic feed cut the specimen

4. Check the specimen with measuring instruments at the end.

8. PROCEDURE:

1. The two ends of the work piece are first smoothened by filing and apply chalk on its surface.

2. Place the work piece in the V -block and mark center on the end face using surface gauge, scriber and Vernier height gauge.

3. Mark square on the end face, according to the required dimensions.

4. By using dot punch made permanent indentation marks on the work piece.

5. The tool is fixed to the tool post such that the tool movement should be exactly perpendicular to the table.

6. The workpiece is then set in the vice such that the tool is just above the work piece.

7. Make sure that line of action of the stroke should be parallel to the surface of the work piece.

8. Give depth of cut by moving the tool and feed is given to the work piece.

9. Continue the process, until the required dimensions are to be obtained.

10. Repeat the process for all the four sides.

9. PRECAUTIONS:

a. Marking should be done accurately.

b. The work piece should be set securely and rigidly in the vice.

c. Before starting a shaper make sure that the work vise, tool, and the ram

d. is securely fastened.

e. Never attempt to remove chips or reach across the table while the table is in motion.

f. Never attempt to adjust a machine while it is in motion

g. Suitable feeds and depth of cut should be maintained uniformly.

h. Apply cutting fluids to the tool and work piece properly.

10. RESULTS: Required specimen obtained according to specified operations with given dimensions

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EXPERIMENT 7

SLOTTING

1. AIM: to make a slot on the given work piece.

2. MATERIALS REQUIRED: mild steel, aluminum.

3. MACHINE REQUIRED: Slotting machine

4. MEASURING INSTRUMENTS: Vernier calipersslip gauges.

5. CUTTING TOOLS: H.S.S.Tool bit of the required slot size.

6. SEQUENCE OF OPERATIONS:

1. Fix the specimen in the three-jaw chuck of the slotting machine .

2. By giving the required feed and depth of cut, the required slot is being made progressively .

7. PROCEDURE:

1. The tool is fixed to the tool post such that the movement should be exactly perpendicular to the table

2. The workpiece is then set in the vice such that the tool is just above the work piece.

3. Adjust the length of the stroke of the ram.

4. Slotting operation is performed and make one slot on the work piece to the required dimensions.

8. PRECAUTIONS:

1. Choose the proper feed and depth of cut.

2. Feed should be controlled to avoid any damage to the cutting tool

3. Lock the index table before starting the operation.

4. Care has to be taken so as to maintain the right feed of the material.

5. Work-wheel interface zone is to be flooded with coolant

9. RESULTS: Required specimen obtained according to specified operations with given dimensions

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EXPARIMENT 8

MILLING

1. AIM: To perform plane milling operation on the given specimen (mild steel) & get to its correct dimensions.

2. MATERIALS REQUIRED: Mild steel specimen.

3. MACHINE REQUIRED: Milling machine

4. MEASURING INSTRUMENTS:Vernier calipers

5. CUTTING TOOLS: Plane (face) milling cutter

6. MARKING TOOLS: steel rule, scriber

a. Work holding fixtures: work piece supporting fixtures

b. Miscellaneous tools: Hammer, brush & Allen key

7. SEQUENCE OF OPERATIONS:

i. Measuring of specimen

ii . Fixing of specimen in the milling m/c.

iii. Giving the correct depth and automatic feed cut the specimen

iv. Check the specimen with Vernier caliper at the end.

8. PROCEDURE:

1. The dimensions of the given rod are checked with the steel rule.

2. The given rod is fixed in the vice provided on the machine table such a, one end of it is projected outside the jaws of the vice.

3. A face milling cutter is mounted on the horizontal milling machine spindle and one end of the rod is face milled, by raising the table so that the end of the rod faces the cutter.

4. The rod is removed from the vice and fitted in the reverse position.

5. The other end of the rod is face milled such that, the length of the job is exactly 100 mm.

6. The table is lowered and the rod is removed from the vice and refitted in it such that, the top face of the rod is projected from the vice jaws.

7. The face milling cutter is removed from the spindle and the arbor is mounted in the spindle; followed by fixing the plain milling cutter.

8. The top surface of the job is slab milled; first giving rough cuts followed by a finish cut.

9. The job is removed from the vice and refitted in it such that, the face opposite to the above, comes to the top and projects above the vice jaws.

10. The top surface of the job is milled in stages; giving finish cuts towards the end such that, the height of the job is exactly 40 mm.

11. The burrs if any along the edges, are removed with the help of the flat file.

PRECAUTIONS:

1. The milling machine must be stopped before setting up or removing a work piece, cutter or other accessory.

2.Never stop the feeding of job when the cutting operation is going on, otherwise the tool will cut deeper at the point where feed is stopped.

3. All the chips should be removed from the cutter. A wiping cloth should be placed on the cutter to protect the hands. The cutter should be rotated in the clockwise direction only for right handed tools.

4. The work piece and cutter should be kept as cool as possible (i.e. coolant should be used where necessary to minimize heat absorption).

5. The table surface should be protected with a wiping cloth.

6. The Tool must be mounted as close to the machine spindle as possible.

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EXPERIMENT 9

CYLINDRICAL SURFACE GRINDING

SURFACE GRINDING

1. AIM: To perform a surface grinding operation on the given work piece.

2. MATERIALS REQUIRED: mild steel specimen.

3. MACHINE REQUIRED: surface grinding machine

4. MEASURING INSTRUMENTS: Vernier calipers, Micrometer.

5. CUTTING TOOLS: Diamond point dressing block.

6. WORK HOLDING FIXTURES: Magnetic chuck

7. MISCELLANEOUS TOOLS: Wire brush (for cleaning the formed chips), Lubricant(coolant),

8. SEQUENCE OF OPERATIONS:

1. Measuring of the specimen using Vernier caliper, screw gauge micro meter

2. Fix the work piece magnetic chuck and lock it

3. Move the specimen close to the moving grinding wheel so that it touches the specimen.

4. Perform the surface grinding operation.

5. Check the final dimension using a vernier caliper, screw gauge micro- meter.

9. PROCEDURE:

1. Workpiece is mounted on magnetic table, so that the line along the face of a grinding wheel coincides with the edge of the workpiece.

2. Depth of cut is given to the work piece by down feed hang wheel.

3. The work piece is reciprocates under the wheel and the table feeds axially between passes to produce flat

Surface and to get the required size of work piece.

10. PRECAUTIONS:

1. Coolant usage is compulsory as the speeds employed are very high and continuous application of coolant is

necessary for ductile materials like steel etc.

2. The grinding tools are first dressed properly.

3. Care has to be taken so as to maintain the right feed of the material.

4. Work-wheel interface zone is to be flooded with coolant

5. Dressing of grinding wheel to be done before the commencement of cutting action, intermittent dressing also to be done if wheel is loaded.

11.RESULTS: Required specimen obtained according to specified operations(surface grinding operation) with

given dimensions

[pic]

CLINDRICAL GRINDING

1. AIM: To perform cylindrical grinding operation on the given work piece.

2. MATERIALS REQUIRED: mild steel specimen.

3. MACHINE REQUIRED: Cylindrical grinding machine

4. MEASURING INSTRUMENTS: Vernier calipers, Micrometer.

5. CUTTING TOOLS: Diamond point dressing block.

6. WORK HOLDING FIXTURES: Holding chuck

7. MISCELLANEOUS TOOLS: Wire brush (for cleaning the formed chips), Lubricant(coolant),

8. SEQUENCE OF OPERATIONS:

1. Measuring the specimen using the Vernier caliper, screw gauge micrometer

2. Fix the work piece onto the magnetic chuck and lock it.

3. Move the specimen close to the moving grinding disc so that it touches the specimen.

4. Perform the cylindrical grinding operation.

5. Check the final dimension using screw gauge micro- meter.

9. PROCEDURE:

1. Work piece is mounted in chuck , so that the line along face of grinding disc coincides with the

Cylindrical surface of work piece.

2. Depth of cut is given to work piece by giving feed to wheel disc.

3. The work piece rotaes continusly and rotating grinding disc grinds the cylindrical surface of work piece

produce finished surface and to get the required size of work piece.

10. PRECAUTIONS:

1. Coolant usage is compulsory as the speeds employed are very high and continuous application of coolant is

necessary for ductile materials like steel etc.

2. The grinding tools are first dressed properly.

3. Care has to be taken so as to maintain the right feed of the material.

4. Work-wheel interface zone is to be flooded with coolant

5. Dressing of grinding wheel to be done before the commencement of cutting action, intermittent dressing also to be done if wheel is loaded.

11.RESULTS: Required specimen obtained according to specified operations(surface grinding operation) with

given dimensions

[pic][pic]

EXPERIMENT 10

GRINDING OF TOOL ANGLES

1 AIM: To cut tool angles on the given work piece.

2. MATERIALS REQUIRED: mild steel specimen.

3. MACHINE REQUIRED: Tool and Cutter grinding machine

4 CUTTING TOOLS: Diamond point dressing block

5. WORK HOLDING FIXTURES: Vice

6. MISCELLANEOUS TOOLS: Wire brush (for cleaning the formed chips), Lubricant(coolant),

7. THEOREY

Tool and Cutter grinders are used mainly to sharpen and recondition multiple tooth cutters like reamers, milling cutters, drills, taps, hobs and other types of tools used in the shop. With various attachments they can also do light surface, cylindrical, and internal grinding to finish such items as a jig, fixture, die and gauge details and sharpen single point tools. They are classified, according to the purpose of grinding into two groups: Universal – tool and cutter grinders Single – purpose tool and cutter grinders. Universal tool and cutter grinders are particularly intended for sharpening of miscellaneous cutters. Single purpose grinders are used for grinding tools such as drills, tool-bits, etc. in large production plants where large amount of grinding work is necessary to keep production tools in proper cutting condition. In addition tools can be ground uniformly and with accurate cutting angles.

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RESULT: Tool angles are obtained according to requirement.

INTRODUCTION TO GENERAL PURPOSE MACHINES –LATHE, DRILLING, MILLING AND SHAPER (STUDY)

PLANNING , SLOTTING , CYLINDRICAL GRINDING, SURFACE GRINDING AND TOOL AND CUTTER GRINDING MACHINE (STUDY)

EXPERIMENT 3

STEP TURNING AND TAPER TURNING ON LATHE

EXPERIMENT 4

THREAD CUTTING AND KNURLING ON LATHE

EXPERIMENT 5

DRILLING AND TAPPING

EXPERIMENT 6

SHAPING AND PLANNING

EXPERIMENT 7

SLOTTING

EXPARIMENT 8

MILLING

EXPERIMENT 9

CYLINDRICAL SURFACE GRINDING

EXPERIMENT 10

GRINDING OF TOOL ANGLES

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