To cut Screw Thread on a Lathe
First make the right diameter with a smaller piece like this.
The smaller piece is for the extension of the chisel.
If you want to make metrical thread, you need a tool with a tip angle of 60 degrees.
Put the Top Slide to 60 degrees.
This its the reason i put the top slide on an angle
I will, that when i cut of some material, it goes from one side. When i don’t do that, my tool tip will certainly break.
Set the tool with a Treading-tool template in the right position.
Now change the wheels to get the right pitch.
Set the turning speed to 100
Don’t forget this. When you forget this , you will lose your lathe. Because the lead screw has a transportation speed for example 1 turn of the head is 1mm moving. So when you turns 1000 rotations a minute and you turn the leadscrew handle, your cutter is at the end of your machine.
I hope you have this thing on your Lathe. It’s a thread dial indicator.
I don’t know the name for it, but it’s very very handy.
I get it off, to let you see that is easy to make.
as you can see are the teeth on the wheel in an angle. You can use right teeth and put the block in an angle. The distance of the teeth must the same as the lead screw.
It’s easy to use. There are a few numbers at the top side. Take one number. It’s turning around slowly when you turn on the machine. When that number is at the line , you turn the “screw handle” and you start to cut your screw thread. When your at the end you can turn off the “screw handle” and go back ( set the top slide 0.1mm deeper ) to do it again.
When you start every time on the same number it will be ok. When you don’t do that, you got a double screw thread. ( sometimes it can be handy )
Maybe in the future i will place a short movie on this page. I said maybe, because movies cost me a lot of bandwidth and a lot of money.
Practise in soft material to get the feeling. 0.05mm at a time.