How does a centrer lathe works?

Answer 1

A metal lathe is used to "turn" (cut) shapes of external and/or internal circular cross-section: cylinders, discs, cones (tapers), spheres (with a special attachment). It can also cut screw-threads to high accuracy; and its range of work can be increased by various extra attachments.

The metal-cutting lathe is the fundamental machine-tool upon which all others depend, and the basic principle of turning - rotating the work-piece against the cutting-tool - has been traced to the Ancient Egyptians perhaps 4000 years ago, for wood-working.

Answer 2

Then the material.

When you do this. Clamp your material so that you can turn your material a little bit and then clamp it good. This piece is difficult to tell , but when you put your material rough in your chuck then is can be like this.

This is immoderate, but it is possible.

We put a “tool” in the “toolpost”.

We use a normal tool.

When you begin with a Lathe i must tell you that every toolpoint must be in the center of the tailstock like this.
When you are an expert , you don’t do this always.

Now turn your tool like this.

On this picture You can see that the backside is further than the point.

This is ( at this moment ) not ok.

On this picture you see that the front is hitting the material instead of the point. This is also not ok.

When you practice a couple of times you will see that this is not good for this kind of tool.

On this picture you see the right position of the tool.

Before we turn on the lathe , we must know the rotation speed of our material. We can calculate this, on this page i show you how.
In this sample we use normal steel with a diameter of 20 mm and a HSS ( High Speed Steel ) tool.
The rotation speed of our material is about 800 turnings/minute.

Move the tool to your material like the picture above and fixate the slide.

Before we turn on the machine Please do your classes on to protect your eyes.

Now we gonna start to make the material “clean” at the front of your piece of material.

I mean to say that we cut of some material so that we hit it every where. Like this.

this is wrong

This is good

Move the tool slowly from the outside to the inside. When it’s not clear ? move the tool 0.1mm to the left and do this again until the surface is clean.
When it’s clean , set the nonius to zero.( i don’t know the right word for it )

use 2 hands for it. One to fix the handle and one to durn the nonius to zero.

On the picture you see one hand, that is because i must held the camera.

So now is one ax to set zero.

Now we do almost the same with the other ax.

Now set the nonius of that ax to zero.

When you messure the diameter then you have set the machine.

Example. You measure a size of 18mm and you want to have 16mm you must cut off 1mm a side. Look out at some machines is the nonius for 1 side and some machines for 2 sides. So if you turn the handwheel to 10, you cut of 0.1mm . On some machines is that
0.2mm.

Answer 3

the metal lathe works via motor belts well the electric one