Do you already own a lathe? If not, they are quite expensive for a usable one. And they have to be large to be rigid enough to cut brass rod of that diameter, so you are looking at something about six to ten feet long, weighing about 500 to 1000 pounds, requiring its own special table and (if you have pets or kids) its own dedicated room.
The first thing you need to learn is how to turn stock and square it up. Then you have all types of cuts that require you to learn how to use that specific cutting tool.
Brass rod stock is stupid expensive right now. In that diameter, the price will make your eyes water.
This is not to be done by someone who just wants to mess around. It is a financial commitment that only really works if you dedicate yourself to making LOTS of mouthpieces.
If you just want to make mouthpiece-shaped objects, you can use one of those Chinese mini lathes that are for sale under many different labels, but they will only work for something trumpet-sized (and that it pushing it) with any sort of accuracy that will net you something that works well enough to give you usable feedback. It will cost you thousands of dollars to rebuild one of these Chinese lathes so that it is even decently accurate, and you must have a high degree of accuracy to make mouthpieces.
Oh, and one other, crucial thing:
Take the price of your intended lathe and double that (at least) for the cost of all the various tooling that you *must* have to do any work. This is something that I was told repeatedly, and I poo-pooed it. "I just need to get the lathe first. Then I'll worry about tooling." Wrong! Without all the cutters and attachments, you have a large, messy, dangerous paperweight.
And a lathe can kill you or put you into the ER *very quickly if you do not practice good toolroom safety measures.
With that in mind, a cheap-ish, small-ish lathe can make adjustments to existing mouthpieces all day, if the swing is large enough for a tuba mouthpiece. Most of the Chinese lathes cannot handle something the size and shape of a tuba mouthpiece. Something like one of the old Sears-Craftsman/Atlas lathes can do this. A Southbend 9" Junior would be perfect, but they are pretty much made of unobtanium and super expensive. I have an East German laboratory lathe that is probably too small to make mouthpieces, and it weighs over a hundred pounds and takes up an entire table in my shop. An old 9" Southbend would probably weigh in at something like 450 to 500 pounds. Usually, you need a 220V line to run one. Mine was wired for the UD home market, so it uses 120V but lacks power because of this.
An old lathe can be a nightmare to locate parts for. Current production lathes that do not suck have plentiful, easy-to-purchase attachments, but they are also pretty costly.
If you were going to start from scratch, I would recommend a Precision-Matthews PM-1022V as an excellent home unit that is affordable (as far as machine tools go).
https://www.precisionmatthews.com/produ ... -pm-1030v/
I love the utility of my commie DDR lathe. It is rigid, accurate, and well-made despite its very small size (for a lathe). But it cost me a lot for something so old, and the attachments are very hard to find and very expensive.
I love my Unimat SL, too, but it is not a serious machine; but more of a super-well-made toy or for hobbyists who work on very small things, and where repeatability is not important.
Whatever you end up doing, I wish you the best of luck!
Wade
My DDR-made lathe…
PS — Modern, high-quality mini lathes are still way too small to turn the stock needed to make a tuba mouthpiece. I mean, you can do it, but you have to have a chuck large enough, and this probably will be next to impossible to find. And the modern mini lathes are just not rigid enough to do that sort of heavy cutting work. Sure, Taig and Sherline are both excellent, not at all like the cheap Sieg-made Chinese lathes. But they are not inexpensive, and the results from such lightweight machines will be something unusable and costly to make.
Small lathes are pretty dangerous when you overload them. Taig and Sherline are the best of the US-made mini lathes. Both are almost as accurate as my Präzi SD 300, and I would not trust my lathe to safely hang on to such a heavy chunk of metal at those speeds. I *would* trust that PM I linked to above. I have used one, and it is excellent, once you clean it up and do proper setup work to the bed and such. (It is not Chinese, but made in Taiwan, and of known good quality, but you still have to do a lot of work to get it ready to use. I think all lathes require a lot of cleaning and setup work to make them run accurately.
I am NOT discouraging you. I am ENCOURAGING you, but warning you of the level of commitment needed to do this work at even a very low level of experimentation.
