Hi Pat,

Welcome to the forum. I made an ER 32 chuck for my small lathe using mild steel. I have used the chuck often for several years without problems. With the use I have I guess the collet chuck will last longer than me.

Thor

Hi Pat

EN8 is a good choice but if new to machining you may find it more difficult to obtain mirror finish and crisp threads because it can be a tough material.
EN1Apb will be the easy material route and may suffice for occasional workshop use.

I would suggest buying a closing nut is worthwhile, especially the ball bearing type.

Emgee

Edited By Emgee on 12/01/2023 18:36:42

My go to choice of metal supplies are M-Machine in Darlington. They do EN1APB. other suppliers are also available.

I would strongly suggest a pre-hardened alloy steel for long term durability and accuracy.

709M40 (EN19 in old money) is widely available in U condition, and 826M40 (EN26) in W condition. West Yorks Steel will sell you both for delivery, via phone or email.

Those letters refer to the tensile strength and hardness as supplied, you would need to turn them with carbide, but the results are usually very good.

Personally I would be inclined to use 080M15 (EN32), do the threaded elements with an allowance for shrinkage, turn to near finished shape, then heat treat myself over a long soak time so the core normalises and the exterior case hardens to a decent depth, then hard turn the register and taper to final size with a CBN insert.

This, obviously is a more complex undertaking, but certainly not beyond the ken of an enthusiastic amateur; if you're curious I can explain in more detail.

Edited By Jelly on 13/01/2023 11:59:04

I'd be tempted to get a few small samples to try before you start the project proper.

See what works for you.

My novice take on different steels is as follows: (bear in mind i'm using home ground toolbits so my geometery may be way off for the material in question.

EN1 leaded, didn't like, 'smeary', marks easy, unlikely to buy again.

EN3~ much better, machines nicely (though a web search suggests it's not so good to machine as EN1) Does seem rather prone to rust however.

EN8~ like others have said, difficult to get a really good finish (at least for a novice like myself) You can tell when cutting it's noticeably harder than mild steels.

EN16T~ (T stands for tempered) Turns quite nice, just from the cutting sound you can tell it's quite hard, gives a good finish, odd colour, yellowy. I blunted a hss threading tool trying to put a thread on it. Probably did something wrong.

EN24T~ My internet research suggested i would have a hard time machining this with hss tools.

Now either i got burned, or the interweb is wrong.

Yes it's quite hard,(but seemed less so than EN16 ??) hss did the job~ beautiful finish, nice shiny silver colour Probably my favourite steel to date.