TubeNet

I have a new toy to play with (a pair of stereolithography "3D printers"). I'm looking for
demonstration projects (mostly to get students interested). Given the mechanical and size
constraints of the cheapo devices I have at the moment, tuba mouthpieces are a perfect fit.

Most (as in 99.9%) mouthpieces can be adequately described by 2 curves - the inner and outer contour (from rim to shank). The outside contour is no problem. The inside contour is a bit more difficult.
Not impossible, by any means - but...tedious.

So, I'm in the market for a few (1 or 2 will do nicely, but the more the merrier) such contours.
There are a few websites with something close to what I need - but they often "intentionally distort" the curves, presumably to slow down potential copiers.

I am *not* in the business of creating or designing mouthpieces, and don't intend to start now. I'm interested in this data "for educational purposes". The only reason I want accurate data is so that I can assess how successful this construction technique is. If I have an original mouthpiece AND a reconstructed one, I can play test them and verify (or not) that the reconstructed ABS plastic mouthpiece is an adequate performer. If it *is*, then it might make sense to play with
oddball variations (such as non-circular cross-sections, or bulbous cups, or...)

so...if you know of a source of such data (or, if you have such data because you make them...and don't mind sharing), please let me know.

Oh...I suppose I'm also interested in mouthpieces for other instruments.

And...if you know of the "best" low-tech device for measuring depth and width of spaces similar
to the inside of a brass mouthpiece, I'm all ears. Making wax models is so messy...

sloan wrote:And...if you know of the "best" low-tech device for measuring depth and width of spaces similar to the inside of a brass mouthpiece, I'm all ears. Making wax models is so messy...

Take a look at Sculpey oven clay.

The standard way to measure holes is using a hole gauge, which includes three feelers and thus assumes circularity, or to use an inside caliper with good technique. A "T" gauge will not work--it requires a cylindrical bore. You have to measure depth. You might set your inside calipers to a given dimension, and then drop them in until they touch, and mark the plane of the rim with a straightedge clamped to the calipers.
http://www.amazon.com/gp/aw/d/B0042SWH7A/

Of course, the prescribe method to use with a stereo lithography machine is to shave a donor in .001 layers and measure the edge with a tracking laser.

Rick "noting these are accurate to no better that .001"--good enough for this" Denney

Perhaps you could saw a kellyberg in half? They're quite cheap enough.

Maybe even saw a slice out of the middle?

If you don't want to be in the mouthpiece business, isn't what you've already found on the world wide web quite good enough for your purposes?

Mike Finn used to have a cutaway picture on his web site. Maybe he might share it with you.

One way to get the inner contour without destroying the mouthpiece is by molten wax. I did this many years ago. First I coated the mpc with a soap film to make it easier to separate the wax. Then I placed the mpc in a pool of molten paraffin in double-boiling pan, arranging it so that the axis of the piece coincided with the surface of the wax. After it cooled and solidified I broke away the wax from the outside of the mouthpiece and carefully removed the inner portion, using hot water to help un-stick the wax. (The thermal conductivity of brass far exceeds that of wax.) Then I placed it flat-side down on a sheet of graph paper and traced the outline with a sharp pencil. (Photography would be better, but this was a long time ago!)

Copying the backbore is more difficult. I used to use soft and fine-grained wood such as willow, and shave it with a sharp knife. After many insertions and twists I could whittle it down to a very accurate inverse copy of the backbore taper.

For your purpose I think sawing a Kelly in half would be much simpler and quicker.

cjk wrote:

If you don't want to be in the mouthpiece business, isn't what you've already found on the world wide web quite good enough for your purposes?

No.