Repair Questions and Other Topics

[Daniel C. Oberloh]

For straight telescopic slide tubes; engine lathe with a single-point thread cutter, followed up with a facing tool and finished off with a three sided scraper to chamfer the inside edge. Or maybe a band-say.

Have you tried a hatchet?

Daniel C. Oberloh
Oberloh Woodwind and Brass Works
http://www.oberloh.com" target="_blank

[Dan Schultz]

Ian...

Of course... as Dan O mentioned... a lathe is the best way to go. But... obviously that requires that the tubes be taken off the horn.

On those occasions where it's not convenient to remove the tubes from the horn AND there is adequate clearance... I get good results using counterbores with interchangeable pilots in a variable speed hand drill. The pilot needs to fit the ID of the tube fairly closely and good speed/pressure control is necessary to keep the cutter from chattering.

Common counterbores of the size required to cut large tubing (1" - 1 1/4") come with HUGE shanks that need to be turned down to fit in a hand drill.

There was some talk on the Delphi Repair Forum about changing the rake on the cutting edge so the counterbore won't 'grab' the brass but I haven't found that to be necessary as long as precise hand control is used.

Some outer tubes on older horns appear to have a rolled edge. But... this is just a piece that soldered to the tube to finish the end where the slide goes in. That piece can be taken off and put back on after the cutting is done.

[J.c. Sherman]

I often use a rotary tool with a fine cutter, when I can't use the lathe (ie tuba still attached to the ax). It takes practice, and you'll want to clean the end up with a tapered grinder for a beveled edge and a tone-hole file for the final touch. Learning to cut straight, though, takes some time and practice.

Have to look into Tinker's idea

J.c.S.

[Rick Denney]

I've used, and seen used, a jeweller's fret saw for tubing that is still on the instrument. It will make a finer kerf than a hacksaw and it will be easier to steer. The blades can be very fine, too. Cutting straight is a matter of skill, which includes the proper body position so that the natural motion of your arm is going in the correct straight line. A very fine flat file can be used to square it up, and a broach can be used to deburr the tube. I usually stuff the tube upstream from the cut with cloth, which prevents the chips from migrating into the instrument. Pulling the cloth out brings the chips with it.

Removing the tube and using a lathe is best, but I'll bet few could look at the tubing I've cut (or that I've seen cut by the above method) and tell that it wasn't done that way at the factory. I've done lots of ugly things during solder practice, but cutting off tubes does not need to be an exercise in the most sophisticated tools possible.

Rick "recalling the story of Renold Schilke shortening the main slide of Jacobs's CSO York using a hacksaw he had stored in his locker" Denney

[Ken Herrick]

A standard hacksaw is one of the poorer options as even with a fine blade they are too large and aggressive to control well. A better choice is a jewellers saw or a 'mini' hacksaw with a very fine blade. Make sure the tubing is held securely, such as with a V block. It is also helpful to reverse the direction of the blade so that the actual cutting is done on a PULL rather than PUSH stroke. Patience is the key word with any saw with practice coming a close second.

The rotary tools such as Dremel are very handy, especially if you have an attachment which holds the tool and a V block to hold the tube set up with a stop so you can turn the tube and maintain its position as the small cutting wheels won't cut tuba size tube in one pass. This type set-up is also good if you are doing more than one tube and want to match the lengths.

Always remember the old carpenter's adage - measure twice - cut once. You can also cut more off but, its pretty hard to cut more on. A fine file, 3 sided scraper, and a large flat fine file such as a tone hole file are handy for finishing.

Of course a lathe with a proper, sharp, well set tool is the nice way to do the job.

JUST an observation............ If you are aspiring to become a top class technician, spend the money on top quality tools and master their use on projects which will return their investment rather than playing around with all kinds of weird and wonderful creations. Buy some beaters, do quality restorations, sell them at a profit, buy more tools and repeat the process. You will enhance your skills, build a reputation, equip your future workshop, and who knows, maybe even make a buck so that when you are well set up, you can afford the time and money to make the more fanciful items on a bespoke basis with somebody else footing the bill. It's a bit along the line of what Dan Oberloh said in a post a while back. Don't just stick something together in a half assed way - strive for perfection.

About a half century ago I used to go to Carl Geyer's shop in Chicago. He never hired apprentices or let other people do his work. WHY? He was a skilled artisan who took great pride in what he did. His name was on what he got paid for and he trusted only his self to produce the quality standard associated with his name. BUT, watching, and listening to him was a good education.

It's your time, effort, money, and career so, of course, it is up to you to decide how you proceed.

All the best,

Ken - not preachin, just obsevin - Herrick