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Achievable tolerances on a hobby lathe

I think you seen a stipple art somewhere and there also a thing like wood burning (pyrography).
So I want to stipple on wood. Just like wood engraving with laser. But I have found that laser can't produce high contrast on wood, i don't know if they just blast away coal particles or it's some kind of another phenomenal.

I have made a simple CNC for tests and shows promise. The only problem is that it takes ages, so I want to increase the number of heads and reduce the dot size for better results.

How about in English this time eh ?

What parts doo you want to make on your hobby lathe ?
Arcadium: You are in Lithuania? Find your local makerspace/hackerpsace/technical college. See if they have a lathe (I did a quick google and there are several sprinkled around your country.) Talk to the people at the makerspace about your project and get some hands-on experience using a lathe. Your money will be MUCH better spent using their machines (some of them looked like some good old cold-war era Eastern European machines which were generally very well made.) You may find that for the cost of a few months membership you get the parts you need and the results you want. You may also find that some of the people at these places have a LOT of experience doing the kind of stuff you want to do... and they speak Lithuanian as their first language. Your English is excellent BTW (FAR better than my Lithuanian!)
Good Luck.

I once did the chuck in a chuck.....overspeeded the big chuck,which relaxed its grip on the 12" 3 j,which went for a turn around the shop at 2000 rpms when the spindle brake grabbed automatically .....for the mechanically challengd ,a Pratt 3j 12" weighs some 100lbs ,and makes a nifty jumping jack come spinning top.
High thermal conductivity, low reactivity at high temperatures, easy to machine...

Sounds like nickel plated copper might be a good bet for your application?

For simple wood burning, nickel plated steel might work just as well. 12L14 since mechanical performance isn't really a concern? As long as the lead content isn't an issue.

Otherwise if you need a truly high performance material that will last a long time you'd be looking at something like Monel or cupronickel.

Also, when pricing your lathe... consider you will end up spending quite a bit in tooling and measuring instruments unless you can score someone's old hobby machine that's already been tooled up. Easily $1,000 if you're serious about the hobby and want quality tools. Hell, I spent that much on my quick change tool post + holders alone because I didn't want Chinesium garbage. Insert tooling extra on top of that, never mind calipers, micrometers, boring bars, precision level, yada yada...

That's not to say you can't get *into* the hobby for less. As long as you have the patience to grind your own tools & keep them sharp, re-center your tools manually after every tool change unless you use a 4-position post and shim stock, etc. Price vs productivity you could say. You'll only get out of it what you're willing to put in. Whether by direct purchase or 'sweat equity'.

+1 for obtaining a used quality machine vs a cheap new Chinese "lathe shaped object" as they're commonly referred to as around here. You'll be hard pressed to find a single person who will recommend a Chinese mini-lathe around here.
The "Mini lathes" probably are just not good in general.

What I am used to calling a "hobby" lathe is (in the USA) a Logan, or Southbend. In the UK, a Boxford, or Myford. Not sure what it would be in other places.

But generally, that class of lathe is made to be able to work to about +- 0.001 inch, which is 0.025mm. A very good operator can, in limited circumstances, do better than that, but the basic construction and tolerances of the machine limit to around 0.025mm.

A "Mini lathe" may not do that well, and the ones I have seen have other problems. The machines I named above were all made to be "light industrial", or school, machines. They were intended to work right, but not made (or priced) for extreme accuracy.

The mini lathes are made to sell, not necessarily to work well.
For less money and far better lathe you can get a sherl*ne. It will handle that size part *better* than 7x12 or 72x120. This will allow you to enjoy the process more - freeing your mind for the saurat-bot design and details.

*better* = easier, It is designed for this size work.
A Sherline is slow and a pain in the butt for anybody used to a SB or Logan. It's good for light cuts only, but you can machine steel. Threading is annoying, but in spite of all that, it will hold reasonable tolerances and has enough accessories to do pretty much anything you'd want, up to its size limits. We have a few at work for specialized jobs and are reasonably happy with them.
I think I could make that part on such a lathe.
A good sharp HSS tool bit. the compound swung for a small increment cross in feed. a few tries to see how close I could get with little worry of going under and expecting hand-finishing from there. A tool bit scalp to center the reamed hole. having a reamer .0002 smaller than my bores size target, knowing that I may need to use that tail center. not uncommon for watchmakers to make a close part on a small lathe when time was not an issue.
Thank you all for the advice. I have never expected so much replies. I will try to look for some smaller Russian made lathes, even though info on them is in Russian and I don't understand it very well.
Also good info on nickel plated material.
I will also ask if I could get hands on experience with a lathe, i think that is a great idea.
Also for the soldering iron tips i have tried them, the problem is that their shafts differ from each other a bit and I would have to press in a sleeve or something and their tips are bent a bit usually which would require quite a bit of tuning.

I was truly pleasantly surprised by this forum.
What's a tolerance?
The tolerances are in the first post
"I need to turn a 8mm in diameter 40mm stickout brass shaft with h8 tolerance (+0; -0.022 mm)
Also I need to ream a 8mm hole in a 10mm brass rod(same stickout), also with a H8 tolerances."

I have figured from all the responses that i could go close to it and use bench stones and files I have some good stones for my woodworking tools and I did some fine honing to a tolerances with them previously without a problem, only difference that this time it will be on a round thing :)
get the machine.

i still have the chinese 3-in-1 i bought 25 years ago for $500 and use it almost every day. i can make that part to less than 10µ tolerance on it. you dont need scraped or hardened and ground ways to do that. my ways have a somewhat "angle grinder look", but its my go to machine for small stuff.

the fastest way to learn machining is on a bad machine that makes you think about whats really going on.

btw, how did you come up with the H/h. its a very sloppy fit even if you hit the middle of the tolerance. play with the machine, make an air spring by precisely fitting a rod into a (blind) cylinder. oil it and see if it holds pressure over night. this way you get a feeling for what you are doing.