Flat G tuning Mod

[EZSlider]

Hey all, I have become interested in modding the tuning on my Gb valve on a new to me and mostly new Bach
50A3. Since it has Hangman valves there are no braces in the way and it seems like a fairly simple trim.
Just looking for a little know how on a guess of how much trim is needed and general tooling. I am a fabricator,
plumber and general fix anything kinda person, but have learned to ask Q's first. Any help greatly appreciated.
Also if anyone has experience with this tuning or G as Mr. Pallard uses I would greatly appreciate that as well.
Thanks a bunch.
Eli

[EZSlider]

Any one point me in the right direction?

[BGuttman]

This is probably a question best asked of a tech. Maybe send a PM to bonearzt and ask him to reply.

Couple of suggestions:

1. Don't use your copper tubing pipe cutter for the trim. It will bend the tubing inwards. This will become a sonic problem on the inner tubes and make the outer tubes not take the inners. I would recommend careful sawing with a jeweler's saw or Dremel. Remember to deburr!

2. If you can't get an answer about how much, look at the slide movement to go from G to Gb. Halve this distance and that's what you need to remove. You may need to make 4 cuts: the outer tubes (obviously) and possibly the two inner tubes as well, depending on how far in the slide can go.

This is a pretty pricey horn to go sawing up if you don't know what you are doing. Maybe that's why you haven't heard much here.

[Matt K]

I probably wouldn't start with your 50A3 on such a project. I'd probably get an inexpensive beater horn and convert the F attachment to Gb or G first once you kind of know how things go. Replacement tubing from Bach can be... slow... and expensive.

I'm not a tech myself but I have some indication that you'd want to use a jewelers saw for the cutting. You'll probably want to measure twice and cut a million times to make sure you aren't cutting off too much at any one point. You'd basically want to take the length of the Gb tuning slide and compare it to the slide crook. Then determine how far G to Gb is in inches/mm/whatever and then cut that distance minus the difference from the tuning slides.

If you do this to another horn first, you'll hopefully get a feel for how much you can cut without going too far. And if you mess up, it isn't a huge deal then.

Post-writeup: Looks like Bruce beat me to the punch so to speak!

[ghmerrill]

Some DIY advice on butchering your instrument (gained from cutting my 1924 tuba from A=435 to 440-ish) ...

A saw is better than a rotary tool like a Dremel. Real hard to cut straight with the rotary tool. I used either a fine tooth hack saw or, at some points, I used one of those singled-handed ones that just hold one end of the blade -- in which case you might want to cut the blade length down to avoid its bending. Also, reverse it (like on a Japanese saw) so it cuts on the draw stroke -- more control, less likely to skip. When I did the second valve slide, I used the Dremel. There just wasn't room to get the saw in there. That went VERY slowly and carefully, and bit by bit.

I also made a little saw out of a jigsaw blade and a handle you can get to hole one of those. A lot of this was because when I cut the valve tuning slides, there wasn't a lot of room to work on that Eb tuba.

Go slowly and plan on multiple cuts with testing in between.

A good file is your friend. Always saw things a bit long, and then use the file to true up the end and get it to the exact length you want. You really can't expect to do that with a saw, and filing brass tubing is a breeze. Of course you have an excellent vise with good and effective soft jaws, right? And you know how to be careful not to deform the tubing when you're doing all this.

And you know to mask off/wrap/protect any other part of the instrument that even MIGHT get in the way of your blade/file. In some cases I used short lengths of angled aluminum stock taped to tubing in order to protect it from file or saw.

I guess that's all the advice I have. It's an adventure.

[elmsandr]

I almost always use a dremel. Good masking is key to making the cuts square as well as keeping the rest of the horn clean (IMO).

After you are done, clean it. Clean and flush again. When you think it is clean, clean and flush it two more times. Grit will kill your valves.

Also, this could be REALLY easy for you to get into trouble... Before you start, buy a couple of extra inner and outer slides. Readily available from OEThayer if you don't have another source.

To figure the length you want, 12th root of 2 is your friend in excel.

I would not do this if it is your only horn, but I am not shy about cutting into valve tubing. The first time is terrifying, but it is not too difficult if you have a particular set of skills.

Cheers,
Andy

[EZSlider]

Haha thank you very much all.. Yes it is for sure an expensive tester but it is what I have.
I greatly appreciate the in put and will keep you up to date. If any one knows resorces that go more into the theory behind the tunings I would appreciate that also. I may start with flat G and play with that first as I can always shorten to G.
Thanks again. Glad to be a part of a nice community here.
Eli

[Matt K]

Talking about the advantages and disadvantages probably makes more sense in the 'Instruments' section. I went ahead and made a topic there sine not everyone who has that knowledge might read this thread. You can find it here.

[ghmerrill]

Re testing, you can go on shopgoodwill.com and buy an old horn for next to nothing. Here's an old Olds beater currently at $10 and with no bids on it. There's even cheaper/junkier stuff there, and shipping/handling usually isn't too much. It's how I practiced (on an old junker broken Chinese trombone with F attachment). With all the other expense you're involved in, even a half hour or hour of practice could save you from a big blooper on an expensive horn. I'll concede that modifying tubing on a trombone is a lot easier than on a fairly closely wrapped tuba, but on the other hand, the risk/reward analysis needs to take into account the downside risk of botching a currently nice and expensive instrument in an instant just as a result of inexperience. I guess I've done my share of botches resulting from impatience, but think I'm finally (mostly?) over that. Probably just self-delusion.

I'm interested to see how you end up. I've often thought that a Gb (rather than an F) attachmeht might be beneficial -- or a double valve indy bass with Gb as the thumb valve. But I haven't wanted to try that even on my modified $500 Schiller since it's set up so nicely now.

[EZSlider]

Sorry for the radio silence. Life has been pretty busy. Had a lil son born on July 14th and my daughter turned 2 a couple of weeks prior. So sleep and playing time have been at a bit of a premium.
I decided to wait a little while before putting my baby under the knife(or cut-off wheel) until I got to know her a bit better. It seems to me that cutting to G is more what would suit me, and I plan to soon. I still might grab a junker to play around on first though. Since my last post my 50A3 suffered a snapped water key, from what is quite clearly a cold solder joint. Still waiting to hear back for Bach as to warranty support. Considered checking with them what they would charge to cut to g for me while they have it. Also wonder if the could screw bell it for me or not, but might try to find another tech for that. Anyone know a good reasonably priced tech in upstate NY?
ghmerrill Thank you so much for all the words of wisdom. I will let you know how things end up.

[Jgittleson]

As far as cutting, i usually use either my lathe or band saw. Then i file it a little and good to go. Id be happy to do the work for you, im on long island.

[doctortrombone]

I avoid jeweler's saws because they leave uneven ends (no matter how careful you are) and they get filings into the work piece. My technique of choice is to mount the tube I'm cutting on a well-fitted mandrel (the back-side, not the part that you use on slides.) That way, you can cut with a tubing cutter and maintain the proper inner diameter. If possible, the mandrel should be solidly mounted, and the tubing cutter should be kept stationary. The tube is rotated on the mandrel itself, thus reducing the chances that the cutting wheel will scar the mandrel.