A lathe machine is a machine whose function is to remove metal from a workpiece to give it the required shape and size.
The workpiece is held firmly by the chuck from each end of the lathe machine.
Lathe machines can be used for several operations which are; drilling, reaming, taper turning, facing, knurling, screw thread cutting, chamfering and many more that I will be discussing in this article.
We can say that a lathe machine is a multi-function machine since it can do several operations without changing the design.
The old thing you will have to change are the bits that will be used in shaping the workpiece
There is much to talk about lathe machines, but I will summarize important points that will make you understand the work of this machine and its several parts.
Type of lathe machines.
There are many types of lathe machines that are designed differently but they all work under the same principle.
I will share with you some of the common lathe machines and give you brief descriptions of them.
Speed lathe; this is the simplest of all lathe machines since it doesn’t have many parts as the other lathe machines that I will be discussing in this article.
The main parts of this lathe machine are; a bed, tailstock, headstock and tool post that is mounted on an adjustable slide.
The speed lathe machine is used in applications that require less force e.g woodworking spinning, centring and polishing.
This lathe machine is very fast hence the name “speed lathe”
Centre lathe or engine lathe; This lathe machine is the one that is mostly used in different industries.
It’s not very different from speed lathe since it contains all the basic parts of the speed lathe except it has a strong headstock and it can be driven at multiple speeds.
There are different types of lathe machines, but they are usually classified according to the methods they use to transmit power to the machines.
We have ba elt drive, individual motor drive and gear head lathe machines.
The centre lathe machine is relatively large compared to the speed lathe since it has many complicated parts.
Bench lathe; This is a small lathe machine that can be mounted on top of a bench hence the name ‘bench’.
The fact that it’s small doesn’t mean that it is not doing some of the operations that are done by speed or centre lathe machine, it has all the parts and it performs all the operations perfectly.
It’s different from the speed and centre lathe machines since it’s small and it only works on small pieces of work.
Toolroom lathe; This lathe is similar to the engine lathe since it contains the same features, the only thing is that it’s much more accurately built.
It has a wide range of spindle speeds ranging from very low quiet to a high speed of 2500 rpm.
This lathe machine is mainly used for precision works on tools, dies, gauges and machining work where high accuracy is needed.
So, when you want to work on tools that need a high accuracy this is the lathe machine that you should go for.
Capstan and Turret lathe; This is a more developed lathe machine compared to the centre lathe.
The main feature that distinguishes this machine from the rest is that the tailstock is replaced by a hexagonal turret which can accommodate different workpieces at once.
All these work pieces held by this hexagonal turret can be fed and worked on in a proper sequence.
With this lathe, you don’t need to reset the work tools since multiple operations can be done at once.
This feature enables this kind of lathe to be more reliable since it can maximize the products produced by this machine.
Special purpose lathes; These are the lathe machines that are designed for special purposes.
They are different from the engine lathe machine as they only work on a certain type of operation.
Examples of special-purpose lathe are; wheel lathe, which is used to finish journals and turn the tread on a railroad car and locomotive wheels.
The gap bed lathe is used to swing extra large diameter pieces. T-lathe machines are used for machining rotors of a jet engine and Duplicating lathe machine which is used to duplicate the shape of a flat or round template on the workpiece.
Automatic lathe; From the word ‘automatic’ this lathe machine is designed in such a style that all the work is done automatically.
The only thing you have to do is to place the workpiece on the machine set your controls and let it do its work.
This type of lathe machine is very fast, very heavy and mass produces the products needed.
Components of lathe machines.
The main components of lathe machines are;
Headstock – the main function of this part is to transmit power to the rest of the lathe machine.
Chuck – This is the part where the workpiece is held firmly.
The bed – This is where the carriage lays and all other parts are mounted on this part.
Carriage – This is that part that helps to move the workpiece and slide it where it’s needed. It can move in a direction parallel to the spindle axis.
Tailstock – The main function of this part is that it gives outer bearing and supports the circular work turned on centres.
Feed mechanism – It’s a combination of different units that involve the moving of the headstock spindle to the carriage of the lathe machine.
The feeding mechanism works in support of other parts too, which are end of bed gearing, feed gear box, lead screw and feed rod.
Threading cutting mechanism – This involves the cutting of threads on the workpiece. The half nut or spit nut is used for cutting threads.
The rotation of lead screw is used to traverse the tool along the workpiece to cut the screw threads.
This rotation is achieved when there is an engagement or disengagement of the carriage with the lead screw.
Working principle of lathe machine.
The workpiece is held firmly at the centre of the bed using chuck and then it’s turned against the cutting tool at a single point, in a specific movement which will shape the job by removing metal from it in form of chips.
If a different shape or size of the change is desired then the workpiece will be reset and the cutting tool will be changed too.
That is if you are using an engine lathe (centre lathe machine), but if you are using an automatic lathe machine then the only thing you will have to worry about is the controls.
Operations of lathe machines.
The operations of lathe machines are so many, in this article I will share with you the common ones.
Taper – This is a uniform increase or decrease in the diameter of a piece measured along its length.
Taper turning – This is when a workpiece is fed into the machine to produce a certain angle, this means it will be fed at a certain angle to achieve that.
Drilling – This is the process of producing holes on jobs.
Facing – This is the operation of smoothing the surface of a job.
Knurling – Putting marking like thread like on a job so that to increase its friction for a grip.
Chamfering – This operation reduces the sharpness on an edge of a workpiece.
Step turning – Reducing the diameter of a different part on the same workpiece.
Threading – This operation is used for cutting threads on the workpiece.
This marks the end of this article, there is so much left to discuss the lathe machines if you have any questions leave your comment.
I have covered the basic part of the lathe machines, but there is still more to cover.
If you would I talk more about it then leave your comment. Thanks for reading, see you in my next article.
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