Tubing Question

[CNCBrass]

Hi all,

I have several projects in various stages that are waiting for the right parts horn to somehow appear out of nowhere. This has inspired me to resurrect a tube drawing bench project that I had in the planning stages many years ago. I have a question for the repair techs and those who have worked on their own project horns. What is the longest length tube you have used or wish you could have used if it were available? Hate to make the bench to short but also don't want it taking up valuable space if it is not necessary.

Thanks in advance,

Dana

[Dan Schultz]

I don't think I've ever had a need for a piece of tubing longer than about 20".

[joh_tuba]

The metric stuff from MW comes in meter lengths.

[J.c. Sherman]

I've had to work with some extraordinarily long lengths of tubing, mostly bell tubes, but also bocals and other unusual parts (contrabass serpent bocal was the longest!). I've never worked with anything longer than 41 inches or so, but beyond 30 inches, things get very, very tricky. The mandrels and other tools make life hell after the distance

Generally, you need 8 inches on either end of a piece to work on for bending. So my 41" piece was initially damn near 4.5' long! My situations, though, are exceptional, and 36" is the longest I'd worry about; 30 should be sufficient for most things.

[Tundratubast]

MNSETC, BIRT in Red Wing, MN has a homemade jig for drawing tubes. They use is for drawing leadpipes and such.
Contact Lucas Pemberton or John Huff, they are the two that could give your the best "How To"
on your quest.

David

[UDELBR]

You can also just do this by hand, obviating the need for a bench. Just put your draw rings / plate in a vice and draw your annealed tube through by hand. Works great, and you can work any length of pipe this way.

[Daniel C. Oberloh]

Very ambitious of you, Dana.
The longest tubes I can recall, are the Holton 345/York like MW/HB50..... 4th valve slide tubes, at roughly 24''.

My shops hydraulic draw-bench has a 46'' draw capacity with a max diameter of 2.5''. So far, I have not really found a need to use it to the max but eventually plan to once I start using it for trombone slide tube repair work (story for another thread on another forum). The mandrels I make for a given project are typically only a bit longer then what I need and no more. For me, fabrication of the tooling is the biggest headache, the longer the draw-mandrel the more complications arise.

Still, it came in very handy for me when I needed to make the outside tuning slide tubes for this restoration project of a 1922 duel bore, Olds bass trombone hand-slide. Fun stuff. Good luck with the project.



Daniel C. Oberloh
Oberloh Woodwind and Brass Works
http://www.oberloh.com

[Daniel C. Oberloh]

Yup, going for the big bucks, Joe.

Dan'l

[CNCBrass]

Thanks for all of the replies. While I have obtained quite a bit of information over the years and have seen the process done, I still have a lot to learn. I plan on controlling the ID while sizing the OD. So this means a mandrel will be required. Experimentation will be required to determine if a short mandrel can be used if held in place via a cable or smaller diameter rod. It will need to be placed and held at the right location in respect to the OD die. Will the work hardening done while reducing the diameter be enough to keep the newly resized tube from continuing to stretch? I can see the real challenge of removing a long mandrel, but maybe I will only need these for the outer tubes so will not have to be real long. I seem to be able to acquire all kinds of odds and ends, but instrument parts. The hydraulic power pack that I plan to use is actually off of a warehouse sweeper. Polishing the dies and mandrels will be the most tedious and time consuming. Fun times ahead!

Dana