Lathe Machine

 Lathe machine is probably the oldest machine tool know to mankind. Its first use dates back to 1300 BC in Egypt. The first lathe was a simple Lathe which is now called a two-person lathe.

In this one person would turn the wood workpiece using rope and the other person would shape the workpiece using a sharp tool.

This design was further improved by the Ancient Romans who added the turning bow and lather the paddle (as there in the sewing machine) was added.

Further during the industrial revolution Steam Engines and water wheel were attached to the Lathe to turn the workpiece to a higher speed which made the work faster and easier.

Then in 1950 servo mechanism was used to control the lathe machine.

From this crude begging and over a period of more than two centuries, the modern engine lathe has evolved. Now we have the most advanced form of the Lathe Machine which is the CNC Lathe Machine.

HENRY MAUDSLAY, a British Engineer is considered as the inventor of the metal lathe.

A lathe machine is a machine tool which removes the 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 feed deep into the work.

A lathe is a machine which is one of the most versatile and widely used machine tool all over the world.

Lathe is also known as the ‘Mother of all Machines’.

Nowadays, Lathe Machine has become a general-purpose machine tool, employed in production and repair work, because it permits a large variety of operations to be performed on it.

Lathe Machine Parts and thre 

The various parts of the Lathe Machine are:

BED:

The bed of the lathe machine is the base on which all the other parts of the lathe are mounted.

The bed is made from Cast iron or nickel cast iron alloy and is supported on broad box-section columns.

Its upper surface is either scraped or grounded and the guiding and the sliding surfaces are provided.

The bed consists of heavy metal slides running lengthwise, with ways or v’s forced upon them. It is rigidly supported by cross griths.

The three major units mounted on bed are:

1.  
2.  

•  

The scrapped or the ground guiding along with the sliding surfaces on the lathe bed ensure the accuracy of the alignment of these three units.

• Headstock:

 

Headstock is present on the left end of the bed.

 

The main function of the headstock is to transmit power to the different parts of the lathe.

 

It supports the main spindle in the bearing and align it properly. It also houses a necessary transmission mechanism with speed changing levers to obtain different speeds.

Accessories mounted on the headstock spindle are:

1. Three jaw chuck.
2. Four jaw chuck.

• Lathe center and lathe dog.

1. Collet chuck.
2. Face Plate.
3. Magnetic chuck.

 

• Tailstock:

Tail stock is a movable casting located opposite to the headstock on the way of the bed. The basic function of the tailstock is:

1. To support the other end of the work when being machined.
2. To hold a tool for performing operations like drilling, reaming, tapping, etc.

It consists of the dead centers, the adjusting screws and the handwheel. The body of the tailstock is adjustable on the base which is mounted on the guideways of the bed and can be moved to and fro.

 

 

• CARRIAGE:

 

Carriage is located between headstock and tailstock. The basic function of the carriage is to support, guide and feed the tool against the job during operation.

It consists of 5 main parts:

1. Saddle: It is an H-shaped casting mounted on the top of the lathe ways. It provides support to cross-slide, compound rest and tool post.

1. Cross Slide:

Cross slide is provided with a female dovetail on one side and assembled on the top of the saddle with its male dovetail.

The top surface of the cross slide is provided with T slots to enable fixing of rear tool post or coolant attachment.

Carriage basically provides a mounted or automatic cross-movement for the cutting tool.

1. Compound Rest:

Compound rest is present on the top of the cross slide. It supports the tool post and cutting tool in its various positions.

Compound rest is necessary for turning angles and boring short tapers and forms on forming tools.

1. Tool Post:

The tool post is mounted on the compound rest. It is used to hold the various cutting tool holders.

The holders rest on a wedge which is shaped on the bottom to fit into a concave-shaped ring(segmental type), which permits the height of the cutting edge to be adjusted by tilting the tool.

It is fixed on the top slide. It gets its movement by the movement of the saddle, cross slide, and top slide.

The three types of tool post which are commonly used are:

1. a) Ring and rocker tool post:

It consists of a circular tool post with a slot for accommodating the tool or tool holder.

b)Quick change tool post