A new tailstock lock handle

Today I made the first useful object with my lathe. The original tailstock lock handle was made from plastic and it was cracked. I made a new one from stainless steel. I used the parting tool to make a simple pattern for a better grip. The thread is M10 and I made it with 3 taps. I polished it with Autosol paste and a felt disc on the grinder. It feels very nice. This is a video with some steps of the process:

Edited By Sonic Escape on 23/04/2023 21:07:13

That has turned out very nice indeed!

I take it the polishing process also softened the edges of the pattern enough to make it comfortable in the hand without removing the nice "crisp arrises" which give it visual appeal.

You were lucky with the stainless, some grades are not nice to machine.

Looking at the chips it looks like one of the ferritic or martensitic stainless steels which fall into machinability class P, the neutral rake on the tool will definitely be helping with getting it to short-chip too which will do no harm.

I have found that kind of stainless to be similar to medium carbon steels when turning but perhaps a bit less forgiving if you don't maintain an even feed, crucially it doesn't do the built up edge behaviour that you get with the Austensic and Duplex grades which really stresses the cutting edge.

Edited By Jelly on 24/04/2023 16:12:56

I cheated a little with those edges. I used a half-round file while the handle was still spinning in the lathe

There is a small aesthetic problem with this method. The parting tool doesn't create a perfect finish. At least I didn't found the right feeding speed. And also you can't polish it well since the channel is quite narrow. But this are small details, it feels very nice when you grab it.

If regular stainless steel is not so easy to machine it make me think if it would not be a good idea to buy another bar. This is not from a shop. A guy made his green house from 5m long bars and now he is selling them. He still has a few left. The price is only 30% higher than normal steel.

Edited By Sonic Escape on 25/04/2023 21:54:30

If its easy to machine and tap then grab it

Most stainless is difficult to work

Agree. There's nothing wrong with metal that cuts OK. Problem is plenty of alloys don't cut well, and some are horrible. Industry choose alloys for particular purposes, and often don't require it to be machinable. What turns up as scrap can be almost anything.

When I started with a lathe I had terrible problems - almost bad enough to put me off completely. Turned out my entire collection of scrap metal was unsuitable. Gummy aluminium, gritty steel, work-hardening stainless, pipes with super-hard welds, and other bad news. Almost by chance I bought some EN1A, which is a mild-steel specifically made to be easily machined. Suddenly the lathe worked properly!

Not realising a metal is difficult is very confusing. Experienced operators recognise difficult metal and adapt, but it's safer to learn how decent metal turns before trying to cut the difficult ones.

When things go wrong in the workshop people tend to blame the tool first. Then, maybe, the operator. (Many have touching faith in themselves, despite not having developed any skills yet!). It's easy to forget the material could be horrible. Now I understand tools and materials better most of my workshop problems are caused by me.

Dave