Parts of Lathe Machine
- Compound slide
- Quick change gearbox
- Feed Shaft
- Lead Screw
It is a fixed unit of lathe on the left hand side. Its main functions are to :
- provide a means to assemble work-holding devices
- transmit the drive from the main motor to the work to make it revolve
- accommodate shafts with fixed and sliding gears for providing a wide range of work speeds
- have shift levers to slide gears to bring in mesh for different speeds
- have a means for lubricating the gears, shafts and bearings.
It is a sliding unit on the bed-ways of the lathe bed. It is situated on the right hand side of the lathe. It is made in two parts, namely the ‘base’ and the ‘body’. The base bottom is machined accurately and has ‘V’grooves
corresponding to the bed-ways. It can be slide over the bed and clamped in any position on the bed by means of the clamping unit. The body of the tailstock is assembled to the base and has a corresponding longitudinal movement as to that of the base, along the bed. It has a limited
transverse movement as well, with respect to the base. Graduations are marked on the rear end of the base and a zero line is marked on the body.
When both zero lines coincide the axis of the tailstock is in line with the axis of the headstock.
The carriage is the part of the lathe which slides over the bed-ways between the headstock and the tail stock.
It provides various movements for the cutting tool manually as well as by power feed. The carriage can be locked on the bed at any desired position by tightening the carriage lock-screw. The tool is provided with the following three movements by the carriage.
Longitudinal feed – with the help of the carriage movement (parallel to the axis of work).
Cross-feed – with the help of the cross-slide movement (perpendicular to the axis of the work).
4) Cross Slide
The bottom of the cross-slide has got a dovetail groove machined, which corresponds to the external dovetail machined on the saddle. The cross-slide is assembled to the saddle with the help of a tapered jib. The adjustment of the jib facilitates the required fit for the movement of the
cross-slide on the saddle. The cross-slide functions perpendicular to the lathe axis either by hand feed or by automatic feed.
A left hand square or acme thread screw-rod fitted with a hand wheel helps in the manual movement of the cross-slide. The automatic feeding is achieved through gearing. A graduated collar mounted on the screw-rod along with the hand wheel helps to set the fine, movements of the cross slide.
5) Compound slide or Compound rest
Compound rest is made of two parts.
• The swivel base
• The top slide
The swivel base is assembled to the top of the cross-slide and may be clamped at any required position between 0° to 360° by tightening the T’ bolts. The head of the bolts moves in the T slot groove on the top of the cross-slide. The swivel base is provided with a dovetail on its top surface
and the top slide has a corresponding dovetail groove. The assembly of the top slide to the swivel base is done by a tapered jib which can be adjusted to control the top slide movement. The sliding of the top slide on the swivel base is accomplished by the help of a screw-rod fitted with a hand wheel and a graduated collar. Only manual operation is possible for the top slide. The top slide assists in feeding the tool to the work.
6) Lathe Bed
Functions of Lathe bed
The two functions of a lathe bed are :
- to locate the fixed units in accurate relationship to each other
- to provide slideways upon which the operating units can be moved.
Constructional features of a lathe bed
In the majority of cases, the bed generally, a single iron casting. In larger machines, the bed may be in two or more sections, accurately assembled together. Web bracings are often employed to increase the rigidity. For
absorbing shock and vibration, the bed should be of considerable weight. Bed castings are usually rough machined and then allowed to ‘age’ naturally before finish machining to remove distortions.
A swarf or a combined swarf and a coolant tray are provided on the lathes. This may be an integral part with the lathe bed. This increases the rigidity of the bed.
The bed generally rests on cast iron or welded sheet metal legs of box section. This provides the necessary working height for the lathe. Very often the electrical switch gear unit and the coolant pump assembly are housed in the box section legs at the headstock end.
The surfaces of the bed in contact with the sliding units of the lathe are known as bed-ways or guide-ways or guide shoars. The beds are classified according to the shape of the ways.