1. Centre lathe

3. The Centre Lathe is used to manufacture cylindrical shapes from a range of materials including; steels and plastics.
Components that assemble to make an car engine work have been made using lathes.
The Lathe may be operated by people (manual lathes) or computer controlled lathes (CNC machines) that have been programmed to carry out a particular task.

4. A basic manual centre lathe
The lathe is controlled by a person turning handles on the top slide and cross slide in order to make a part.

5. Lathe Parts Lathe bed Made from rigid cast Iron
Accurately machined slideways
Slideways guide carriage & tailstock
Headstock on upper end of the lathe bed

6. Lathe parts Headstock Holds lathe spindle and gears
Chuck is fitted to spindle
Spindle is hollow for long bars

7. Lathe parts Tailstock Can be moved along slideways Can be clamped
in any location
Inside tapered
to hold drill chuck

8. Lathe parts Carriage Moves along bed between tailstock and headstock
Saddle – across the lathe
Apron – hangs down in front

9. Lathe parts Cross Slide Fitted on the Saddle
Moves cutting tool at right angles to lathe bed

10. Top Slide (Compound slide)
Lathe parts
Top Slide (Compound slide)
Fitted to top of Cross slide
Carries toolpost and cutting tool
Can rotate to any angle
Is used to turn tapers

11. Lathe parts Feed shaft Lead screw
Used to move the Carriage automatically
Lead screw
Used when screw cutting on the lathe

12. Lathe Parts Three Jaw Chuck Holds round and hexagonal work
Self centring
Holds round and hexagonal work
3 jaws are connected
Jaws are stamped 1,2 & 3 and fitted in order
Chuck key used to open

13. Lathe parts
Toolpost
Fitted on top slide and carries the cutting tool or the cutting tool holder
Can adjust the height on some types
Can carry 4 different tool holders

14. Lathe parts Tool holders Used for holding cutting tool bits
Available in Right hand, left hand and straight

15. Cutting Tools Can be High Speed Steel held in tool holders
Can be also Ceramic (Tungsten carbide) bits held directly in toolpost

16. Cutting Tool Angle Clearance angle
Ensures only the cutting edge of the tool touches the work
Too much clearance causes chatter

17. Cutting tool angle Rake Angle Allows the chip being cut to flow out
Changing the rake changes the power used in cutting and the heat generated
Large rake = soft ductile materials
Small rake = hard brittle materials

18. Cutting tool angle
Tool bits are held in holders at an angle of about 15°

19. Cutting tools
We can put different shapes on the High speed tool bits to cut different shapes on the workpiece

20. Lathe operations
Facing off
Parallel Turning

21. Parallel Turning
The tool moved parallel to the work and cylindrical shapes are
formed
Also known as sliding

22. Parallel Turning
The student can Parallel turn the work on the lathe manually or use the automatic traverse option

23. Facing off
The tool is moved at right angles to the work using the cross slide
Flat surfaces are produced

24. Knurling
A knurling tool is used to press a pattern onto a round section.
The pattern is normally used as a grip for a handle.
This provide a grip for the round part
e.g. Screwdriver

25. Knurling

26. Parting off
If the student wants to cut off the part they have turned, they can use the hacksaw and a vice or use the parting off tool on the lathe.

27. Setting the tool height
The cutting tool on the lathe must be set to the exact centre of the work-piece
We use the centre of the tailstock to guide us to the correct height

28. Screw-cutting on the lathe
Lathes are also used to cut threads in round bars
These threads take up different profiles e.g iso (60°) ACME etc.
These threads can be seen on bench vices, lathes etc.

29. CNC Lathes

30. In Industry it is not efficient or profitable to make everyday products by hand.
On a CNC machine it is possible to make hundreds of the same item in a day.
First a design is drawn using design software, then it is processed by the computer and made using the CNC machine.
In industry, CNC machines can be extremely large.

31. LATHE OPERATIONS Producing a Flat Surface
LATHE OPERATIONS
Producing a Flat Surface
Producing a Cylindrical Surface .
Taper Turning

32. Radius Turning Attachment
Drilling on a Lathe
Parting Off / Under Cutting