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20J customize?

Posted: Mon Jun 11, 2018 3:40 pm
by bigboymusic
While I know anything is possible, I am asking our gurus that know this stuff about whether or not it would be worth the attempt.

20J body with a Kanstul upright bell, reversed to accept front action
either a King 4V set plus a 5th rotor or the preference, a 4 or 5 Valve MeinlSchmidt rotor set

I already have the bell sitting and waiting for the day.... And finding a 20J body is quite easy... My mind thinks this would be worth the attempt at a beautiful sounding, in-tune 6/4 Bflat...

Thoughts amigos????

Re: 20J customize?

Posted: Mon Jun 11, 2018 5:35 pm
by bort
You might want to talk to Norm Epley. A few years ago, he grafted a Cerveny rotor section to a big Conn. I can't remember if it was in BBb or CC. I think it turned out pretty well...?

Re: 20J customize?

Posted: Mon Jun 11, 2018 7:26 pm
by The Big Ben
bigboymusic wrote:While I know anything is possible, I am asking our gurus that know this stuff about whether or not it would be worth the attempt.

20J body with a Kanstul upright bell, reversed to accept front action
either a King 4V set plus a 5th rotor or the preference, a 4 or 5 Valve MeinlSchmidt rotor set

I already have the bell sitting and waiting for the day.... And finding a 20J body is quite easy... My mind thinks this would be worth the attempt at a beautiful sounding, in-tune 6/4 Bflat...

Thoughts amigos????
Art Hovey built one such as you suggest but with a recording bell:

http://galvanizedjazz.com/tuba/20J/20Jconversion.html" target="_blank

Re: 20J customize?

Posted: Mon Jun 11, 2018 8:38 pm
by Donn
The Big Ben wrote:Art Hovey built one such as you suggest but with a recording bell:

http://galvanizedjazz.com/tuba/20J/20Jconversion.html" target="_blank" target="_blank
Wow - his modest, matter of fact account almost makes that sound like an easy job.

Is that the way it's usually done, using a rotary grinder to thin large bow tenon joints to fit? I've seen a repairman use a sort of crimper like thing to enlarge a small tenon, which seems like it would be easier as you'd naturally maintain a constant thickness, but making the tenon smaller might not be so easy.

Re: 20J customize?

Posted: Mon Jun 11, 2018 11:22 pm
by Art Hovey
Adam Crowe now owns that tuba. He added a Kanstul upright bell and has used it in a concert with the New Haven Symphony.
Doing the conversion wasn't exactly "easy", but I was able to do it with only a moderate amount of skill and simple equipment.
It was just something I had always wanted to try and it worked out. I have no idea how a real tuba mechanic would do it, but it can be done.
If money were no object I would choose a Meinl-Weston valve section.

Re: 20J customize?

Posted: Mon Jun 11, 2018 11:33 pm
by TUbajohn20J
Go for it if you have the skill or have the means to pay for the work. Or you could buy a 36J and have the horn you are wanting already made from the factory. Or, if you are wanting to keep it short action you can buy a 22K sousa valve section and possibly use the 2nd valve of the 20J to make the 4th valve. Yes the 20J valve would be a slightly larger bore but that will be good for a 4th valve and really open up the low range. Keep us posted!

Re: 20J customize?

Posted: Mon Jun 11, 2018 11:38 pm
by Kirley
Here is an old thread from someone who converted a 20J to a front action horn using a 20K (slightly smaller bore) valve section:
viewtopic.php?f=2&t=39070" target="_blank