Posted by John Swensen on August 21, 2002 at 11:45:30:
In Reply to: fire up the smithy for our own mp's posted by Shane Ackbar on August 20, 2002 at 21:59:42:
I have not made a complete mouthpiece from scratch, but I have adapted mouthieces to screw rims and I have made a few rims. It's fun, but no way to save money.
The smallest lathe that can handle tuba mouthpieces is the tiny Sherline, which costs between $500 and $1000, depending on how many accessories you buy with it (you can use a surprising number of them, so that tooling and accessories accounts for at least the same value as a basic lathe (of any size). If you don't, already, have one, a grinder for tool bits will run you between $50 and $100 for an import, plus another $30-50 for decent grinding wheels, plus $30 for a wheel dresser.
Cutlery is, usually, 420 stainless steel, and melts at white-hot temperatures; fishing weights are lead, which is too toxic for me to put anywhere near my mouth. Mouthpieces are, traditionally, made of free-machining brass (made so by adding small amounts of lead to encourage machining chips to separate cleanly from the metal, rather than tearing), which is silver plated to slow tarnishing. You can buy brass from a metal recycler (just about all of their round, bar, and hex stock will be free-machining), or from a machinery supply place like MSC. Alternatives are nickel silver (actually, no silver at all; just brass with about 15-18% nickel to make it white), or bronze (which is very difficult to machine). Stainless steel would be tarnish free, about as heavy as brass, and very difficult to machine. Plastics (acrylic, polycarbonate, or Delrin) are other possibilites, and they are much lighter, often transparent, and don't require plating.
Tuba rims are between 1 3/4" and 1 7/8" in diameter, cups are between 1 1/4" and 1 1/2" in diameter, and shanks are around 3/4" in diameter. You could machine rim-sized stock down to a complete mouthpiece, but it will take a while, and you will be turning lots of expensive brass into chips (machine shops sell their brass chips to metal recyclers). Alternatively, you could make each piece separately, threading them together, but this requires threading capability (another accessory for Sherline lathes, often comes built-in to larger lathes).
Once you have your lathe, you need to machine reamers for backbores (O-1 steel, machined to the desired taper, ground to a D-shape, then hardened and tempered, then polished and sharpened), and lots of jigs, tooling, and mandrels to hold the parts accurately and firmly as they are being cut; aluminum will do for occasional use, but should be machined to attach directly to the lathe's drive spindle or collet for accuracy and repeatability.
So, for the price of a handful of Monette mouthpieces, you can start making your own. The first will, probably, not be as good as those you can buy, but you can experiment to your heart's content, particularly if you opt for the screw-rim, screw-shank approach.