TromboneChat

I seem to remember at some point that Shires made in-between (1/4 size) leadpipes. Is that correct? Has anyone ever seen a 1.75 leadpipe? 2.25?

We used to do them as custom orders. Not sure what they would do now. Also, there was a dealer at one point who had us make 1.8 and 2.3 pipes in every bore size, so there are some of those out in the wild.

How does one "size" a leadpipe? Given the 3d nature of the shape and the number of design variables it's not obvious to me how to describe how one differs from another.

I have three 2.25 pipes I had made about 8-10yrs ago. Not 100% sure but I think they don't do that kind of stuff anymore. (you could ask, the worst they'll say is "no")

baileyman wrote: ↑Fri Nov 02, 2018 7:33 am How does one "size" a leadpipe? Given the 3d nature of the shape and the number of design variables it's not obvious to me how to describe how one differs from another.

In the case of Shires - and I presume Edwards - they have one shape and rate of taper they use for all leadpipes in the same bore. The size numbers within that refer to the diameter of the venturi - the smallest point of the taper after the end of the mouthpiece.

To make a leadpipe they draw a tapered tube and cut it to length. Where exactly along the taper they cut it determines which size number it is. Then the mouthpiece receiver is shaped by flaring the tube at the small end.

Trumpet leadpipes and some makers' trombone leadpipes (King, for example, and I've also seen this on a Jupiter XO large bore tenor) are made a little differently, without flaring the mouthpiece receiver but instead soldering a machined receiver on.

Ah, very helpful, thanks.

It would seem then that if Venturi diameter is the sizing point and the taper is constant, then the lengths of the tubes would vary depending on slide bore together with Venturi size (smaller should imply longer length to get from the small Venturi to the slide bore at constant taper).

So the Bach #402 pipe that came in my MV9 slide and is very short and barks like a dog must be a relatively large Venturi, whereas the one I prefer that behaves smoothly until I want that cutting sound and is almost twice as long must have a relatively small Venturi.

There is usually a straight section at the large end of large bore and bass lead pipes, so the length can be a separate variable from the venturi. For example, Edwards trims their sterling silver leadpipes to a different length than their brass leadpipes.

Cheers,
Andy