1. …………..Continued Recap Machine tool Lathe machine Basic components
Functions

2. Unit 4 Machine Tools Machine Tools (Basic Elements, Working principle
and Types of Operations)
Lathe Machine – Centre Lathe
Drilling Machine – Radial Drilling Machine
Grinding Machine -Surface grinding, cylindrical
grinding, centerless grinding, All
operations

3. Operations performed on the Centre Lathe Machine
1. Turning – a. Straight Turning b. Taper Turning 2. Facing 3. Parting off 4. Chamfering 5. Knurling 6. Grooving 7. Thread Cutting 8. Drilling 9. Reaming 10. Boring

4. Operations on Lathe .. Turning ..
machine length of job to reduce diameter of Job
Cutting Tool: Turning Tool
Feed:
in direction parallel to work piece axis
Depth of Cut:
in direction perpendicular to work- piece axis

5. Turning ..
Operations on Lathe ..
Cylindrical job

6. Turning

7. Turning ..
Operations on Lathe ..
Cylindrical job

8. Facing .. Operations on Lathe .. machine end of job  Flat surface
or to Reduce Length of Job
Cutting Tool: Turning Tool
Feed: in direction perpendicular to workpiece axis
Length of Tool Travel = radius of workpiece
Depth of Cut: in direction parallel to workpiece axis

9. Flat Surface/Reduce length
Facing
Operations on Lathe ..
Flat Surface/Reduce length

10. Facing

11. Facing

12. Taper Turning

13. Taper Turning

14. Operations on Lathe ..
Knurling

15. Knurling

16. Knurling

17. Operations on Lathe ..
Grooving
Produces a Groove on workpiece
Shape of tool  shape of groove
Carried out using Grooving Tool

18. Operations on Lathe ..
Grooving ..

20. Parting Off/cutting off ..
Operations on Lathe ..

22. Operations performed on the Centre Lathe Machine
1.TURNING OPERATION:
2. FACING OPERATION:
In this operation a flat surface is produced at the either end of the work piece. Thus by facing operation the length of the work piece gets reduced.
The tool used for this operation is known as Facing Tool or regular Turning Tool, which is clamped in the tool post. The tool moves crosswise perpendicular to the centre line of the lathe machine with the help of Cross Slide. The feed rate is provided to the tool with the help of Carriage. During this operation the work piece may be rotated at higher speeds.
3. PARTING OFF / CUTOFFOPERATION:
In this operation, specific part of the work piece is removed (detached) from the total length of the work piece. The tool used for this operation is known as Parting Off Tool. The tool moves specific lengthwise which is parallel to the centre line of the lathe machine with the help of Carriage. The feed rate is provided with the help of Cross Slide. During this operation the work piece is rotated at lower speed.

23. Operations performed on the Centre Lathe Machine
4. CHAMFERING OPERATION:
Basic of this operation is to remove sharp edges on the work piece by required angle. The tool used for this operation is known as Chamfering Tool and having the tip angle of 45o or 60o. The tool moves specific lengthwise which is parallel to the centre line of the lathe machine with the help of Carriage. The feed rate is provided with the help of Cross Slide. During this operation the work piece may be rotated at higher speeds.
5. KNURLING OPERATION:
In this operation, diamond shape pattern is embossed over the surface of the work piece. Knurling is useful to grip the work piece or the part of the work piece firmly. The tool used for this operation is known as Knurling Tool, which consists of set of hardened steel rollers. The tool moves specific lengthwise which is parallel to the centre line of the lathe machine with the help of Carriage. The feed rate is provided with the help of Cross Slide. During this operation the work piece is rotated at lower speed.

24. Operations performed on the Centre Lathe Machine
6. GROOVING OPERATION:
In this operation, the diameter of the work piece is reduced over a small narrow surface for particular length of the work piece. The tool used for this operation is known as Grooving Tool. The tool moves specific lengthwise which is parallel to the centre line of the lathe machine with the help of Carriage. The feed rate is provided with the help of Cross Slide. During this operation the work piece is rotated at lower speed.

25. Operations performed on the Centre Lathe Machine –
7. THREAD CUTTING OPERATION:
In this operation, helical grooves are produced over the cylindrical surface of the work piece. For thread cutting operation definite relationship between the rotation of the work piece in the Spindle and longitudinal travel of the Carriage is required. This is done with the help of engagement of the lead screw. After engagement of lead screw the whole Carriage unit moves forwards (from tailstock towards headstock) and backwards (from headstock towards tailstock) by controlling the levers that are provided on the apron unit. The tool moves specific lengthwise which is parallel to the centre line of the lathe machine. The feed rate is provided with the help of Cross Slide. During this operation the work piece is rotated at very lower speed.

26. Operations performed on the Centre Lathe Machine –
8. DRILLING OPERATION:
In this operation, a cylindrical hole is produced in a work piece, by cutting edge of a cutter known as the drill. The drill bit is fitted into the barrel of the tailstock (drill is stationary). First the drill is bringing in contact to the work piece. In this position the tailstock is locked on to the bed with the help of lever provided on the tailstock, so as to avoid the backward movement of the tailstock. The feed is given to the drill with the help of hand wheel which is provided on the tailstock. Before drilling operation, centre is marked on the either face of the work piece with the help of centre drill. This is required so as to avoid the eccentricity or taper of the hole into the work piece. During the operation the drill moves in longitudinal direction which is parallel to the centre line of the lathe machine. During this operation the work piece is rotated at lower speed.

27. Operations performed on the Centre Lathe Machine –
9. BORING OPERATION:
In this operation, the hole is enlarged, which has been produced previously by drilling, casting or forging. Boring cannot originate a hole like drilling. Boring is used to correct error in concentricity and alignment in the previously drilled hole. The operation of boring is same as drilling operation.
10. REAMING OPERATION:
It provides sizing and finishing to the already drilled hole. Operation of tool and movement of tool is same like drilling operation. The tool used for reaming operation is known as reamer, which has multiple cutting edges. Reamer cannot originate a hole. It simply follows the path which has been previously drilled and removes a very small amount of material.

28. Operations performed on the Centre Lathe Machine –
11. Contour Turning
A typical shape / curve is by using a single point tool.
12. Form Turning
The shape of the tool is replicated on the workpiece.

29. Lathe operations
Turning, Facing, Parting, Thread cutting, Grooving, Reaming & drilling, Boring, Knurling
Milling, Grinding, Tapping, Spinning etc.

30. BORING OPERATION:
DRILLING OPERATION:
Form Turning

31. Lathe operations

32. Thread Cutting Mechanism