TubaForum.net

Hogging out a Willson rotor to unRotax it…?

Anyone happen to have pictures of a Willson rotor before and after removing the material that defines it as a Rotax rotor? Really curious to see one of these in the final modified form and to see >>>how far the surgery is usually taken<<< (especially by Martin Wilk).

Anyone ever do this/have this done to the 5th valve on a 3400 piston Eb? If so, what are your thoughts…?

Thanks for reading.

Stay tuned… I’m having this done in about a month, but I believe @bort2.0 had this done to his rotor 3050 with good results.

They really don't get "hogged out"...Stuff that's removed is only on the surface and on the outside surface of that inside (prior to cutting) "tunnel".

Basically, you cut all of this bore-restricting stuff away (to make it like a traditional rotor) and smooth down the edges - so that it doesn't scrape in the casing.

Tunnel becomes a trench… I’m just curious how much is being removed. Are most people going straight from “circle to circle” or are they do more what you drew and using a slight arch like a normal rotor. Using a straight path (no arch) might be more in line with the “MAW” concept used in those pistons and involve more of the casing as an active air path. Would there be a benefit to that is my curiosity.

I would dip down in the middle - and just copy the style of a classic/typical rotor.
If you can file down thin in than center dipped-down area, all the better.

- more bore
- less weight

Looks like you need a dipstick to finish that out. Oh wait….

That’s where I’m at. More bore and less weight should only be an improved situation. Looking forward to hopefully seeing some examples.

The reason I’m asking is that I have a Willson (4 piston + 1 rotor) 3400 Eb in lacquer here. I’ve had it a number of years now. Not 100% sure when it was made, but know the ballpark. I imagine they exist, but I’ve never seen another one like it. Gold brass leadpipe rather than nickel, etc. It was formerly owned by the DC Navy band. I learned that it was ordered and then the intended player moved on (retired, didn’t reup, etc.). One of the next players wanted an F and, as I understand it, they are allowed to order what ever they want when the time is right. So, this sat unused. Gorgeous condition. Finish is perfect, has one small ding that I can find. I really dig the lacquer finish, too.

Anywho, when I got my paws on it, I discovered that it had double or triple thickness of felts stuck under the caps. Valves waaaaay out of alignment. Why? I have a theory, but I don’t know… Played less than optimal! Once I gave it a once over and sorted it out, it is just a dandy tuba. I’ve never played another 3400 this nice. A very lucky purchase of opportunity!

This tuba plays so incredibly well and balanced that I’d hate to mess it up, but I’m curious about this modification hence my on-going research on the rotor mod. It would be great to A-B it with an unmodified/modified rotor, but that might be a little tough to pull off!

From my discussion with Martin, and others, this modification is really nice for the all-rotary Willson tubas. If nothing else, the weight loss will make it 100% worth it to me.

Like you, I had considered doing this with my piston 3200 F, but moved it on before I had the chance. For just a thumb rotor though, I didn’t notice too much of an issue concerning the weight aspect of the one rotor. It is really noticeable when all 5 valves are those rotax valves, though. From what I can gather you’re looking more for an improvement in airflow/response, yes? I’m not sure you’d see too big of a difference with just the one valve, but who knows?

Thanks for that info! That’s what I was wondering regards to doing just 5th valve. Very interesting and something to think about.

Once you cut it, you'll probably want to take a file and back file it, and that's when you need to be careful.

I had Martin Wilk do the work for me... I'll have to see if I have photos somewhere. I seem to remember dropping the ball on that and withe having no photos, or really lousy photos.

For an all-rotor Wilson, I would un-Rotax again in a second.
For the rotor in a 4P+1R... I wouldn't be in much of a hurry.

bort2.0 wrote: ↑Mon Jun 17, 2024 8:34 pm For an all-rotor Wilson, I would un-Rotax again in a second.
For the rotor in a 4P+1R... I wouldn't be in much of a hurry.

yup.
The fifth lever set-ups on Willson piston tubas make the 5th rotors feel heavy - whether-or-not the rotors themselves are heavy.

In typical Willson fashion… over-engineered and too heavy.

The benefit of only having the one rotor done is that you’ll only need to pay for one valve!

I wonder if just doing the one valve will feel a little more “open” when using it. I just don’t think the Willson Eb and F tubas are challenging to play below the staff anyway, so any benefit you might get may be minuscule at most.

If it were me… I’d probably do it if I had the option. Just one less Willson weird thing that you’d need to deal with.

I won’t call it a “fleeting thought,” but I’ll have to cross all the “i’s” and dot all “t’s” before/if I go after it.

Regarding all the Willson over engineering, yeah, it can be heavy in the hand, but it sure is SOLID! Every time I pick it up, I admire it. I have to say, I’m glad I got it when I did.

Thanks to all who took time to respond to this thread!

I played a borrowed 3050 for about a year, and I don't think it was good for my tuba playing health.
I had never been much of a contrabass tuba player, and there were several years that I only owned an F tuba and played every job on it. I decided to audition for a full-time orchestra job, and borrowed the thing to play the low excerpts and use it for the audition. The one good thing I can say about it is that it is dent resistant. I think my contrabass tuba mastery did improve, I actually made the finals at that audition (which is a synonym for failure and $0), but I also developed some habits of working too hard to play, which meant that later I had to rid myself of those habits.

I don’t know much about their CC/BBb tubas. They’re definitely heavy. The one thing I do remember is thinking that the player feedback was different. Seemed like a challenge to know/understand what sort of product was being produced, if that makes sense. I imagine its just part of a learning curve.

I would look at their original piston E-flat tuba that Marty Erickson was promoting when it first came out, if I were more of an E-flat player, if it was constructed of normal thickness material, and if it had some sort of really easy on-the-fly way to play low G without playing it a mile sharp - as it has only five valves, and that pitch is far too commonly requested in all sorts of written tuba music.

The Gronitz PCK tuba is far from a perfect instrument, but it's astonishing how different it and the Willson 3050 are, considering that one has to look fairly closely to be able to tell them apart.

234 is pretty good to go on this 3400.

I went and googled the 3050 and PCK. They don’t look all that similar from internet pictures to me. The 3050 seemed pretty consistent. The PCK looks to have had quite a bit of variation (inner bows, upper bow to bell, etc.). Maybe up close and in person it’s different. Didn’t run across a side by side of any version.

Or maybe…

“They are similar… just because they’re toobas…”

Size/profile-wise, they are just about precisely the same.
Otherwise, they both have four pistons which are right at the same bore sizes and a larger bore rotor.