Question about rotor valves

[Dan Schultz]

Go to http://www.mcmaster.com/ and look for Amber Polyurethane Rod 1/4" Diameter, 6" Length part numbers 8784K821 (40A Durometer hardness) or 8784K822 (60A Durometer hardness). Some people like the harder one for the stop and the softer for the return.

Posted: Sat Feb 04, 2006 3:01 am

I followed Bandmaster's recommendation and bought the polyurethane rods from McMaster-Carr.

I got to the point in the order where they asked for my credit card number, but they had not given the shipping charges. It is my policy with online purchases to not give a credit card number without knowing the total price that will be charged to my card, and I sent them feedback to that effect.

MA

I've been buying stuff from McMaster-Carr for years. They haven't caused any problems for me at all.

[Dan Schultz]

...Oiling it with Hetman Bearing and Linkage oil helps for a while, but isn't a permanent fix. I need to find a source for those ball ends.

This thread recommends a source for these:
viewtopic.php?t=25980

I did a little research on these on McMaster (even before it was posted here, no less) and I may have finally found a source for these.

If you type "ball joint rod ends" into the search at McMaster-Carr, click "ball joint rod ends," then click "high strength ball joint rod ends" you should be able to customize a rod end to fit your horn.


....of course this is all assuming that MC has ends that will fit our horns. Perhaps someone with a caliper (Tubatinker ) and a few extra minutes could see if these migh work for our uses.

It might be difficult finding an EXACT match for what's already on your horn. Often, I find it quicker, easier, and much less expensive to just replace all of the ball links with hardware from DuBro. The DuBro links are plastic but I've found them to be very robust. For rotary tubas, the #4-40 units seem to be the easiest to incorporate. Where threads are required, just retap the existing holes to #4-40. In some cases, you can simply drill out the mounting hole and use the locking nut on the backside... as is the case on paddle lever arms. Here's the link:

http://www.shopatron.com/index/101.0.5210.5163.0.0.0

[Dan Schultz]

The smallest that McM/C seems to carry is 6-32 thread with an 1/8" hole, which is pretty chunky.

The vast majority of rotor-related noise is caused by VERTICAL BEARING PLAY in the rotor itself.

The Bloke is correct. Normally, the only reason to replace a link is if it is broken. Even the old 'S' links aren't normally the source of rotor noise.

[Rick Denney]

The smallest that McM/C seems to carry is 6-32 thread with an 1/8" hole, which is pretty chunky.

True, but the mention of McMaster-Carr related to the 1/4" plastic rod used for bumpers.

But I do find everything needed for a conversion to ball ends at McMaster except for the ball joints themselves. Those are readily available at any hobby shop that caters to radio-controlled airplanes, and especially radio-controlled helicopters.

The hobby store will have 4-40 threaded rod in plain steel, but McM has it also in brass and stainless, for example.

Rick "whose rotary valves have always been noisy because of lateral play in the bearings" Denney

[Rick Denney]

Rick "whose rotary valves have always been noisy because of lateral play in the bearings" Denney

Same here. I think three of the five valve ball ends on my horn click obnoxiously. I can hear them clicking and I can definitely see WHY they're clicking if I stop the valve from rotating. There's lots of play in them, and in one of them it's enough that Hetman Bearing & Linkage doesn't help.

Different bearings. I was referring to the rotor shaft bearings, not the ball links.

My ball links are ALL the Du-Bro type mentioned by Dan. Those never, ever make noise. And if they wear enough to rattle a bit, a quarter turn on the screw eliminates that play.

On the subject of linkages, allow me to be even more pedantic than usual and propose a series of requirements. These requirements related directly to what tuba player do with their tubas:

1. The linkage shall move the rotor solidly in response to finger motion on the paddle. ("Solidly" would need to be defined.)

2. The linkage shall not make audible noise. (It's a tuba, not a percussion instrument.)

3. The linkage shall not allow detectable play. (This could be refined to limit play to some acceptably small number.)

4. The linkage shall not create friction. (Again, should be refined to some acceptably small measure.)

5. The linkage shall fulfill these requirements for the life of the instrument.

6. The linkage shall be routinely serviceable without disassembly or the use of special tools or techniques.

NONE of the metal-on-metal ball links that I have seen will fulfill all these requirements as well as the plastic Du-Bro ball links. The adjustability of the ball links is how they respond to Requirement 5. The composition of the plastic responds will to Requirement 4. The open nature of the link, and the easy adjustment, responds to Requirement 6. And so on.

I didn't include the requirements important to manufacturers and some repair folk. They are:

7. The linkage shall look expensive.

8. The linkage shall look strong.

None of the 4-40 ball links of any description have a problem with strength. Breaking one is nearly impossible, even with abuse. But folks think the shiny metal ball links look fancier than the clunky plastic Du-Bro links. So be it. I just can't find a way to connect that requirement to anything important to how the instrument plays.

Given that my linkages do not have excessive play or make noise, any noise they make must come from somewhere else. There are only two possibilities: The bearing between the lever and the lever shaft, and the rotor bearings themselves. The lever shafts are preloaded with a spring, and even when loose won't rattle. Thus, any mechanical clatter must be in the rotor bearing.

And metallic clank is different from bumper noise that even piston valves have to minimize. Replacing bumpers can only fix bumper noise and maladjustment. It can't fix any other source of noise.

Rick "who replaced linkages of all types that clearly didn't meet those requirements" Denney

[WakinAZ]

...I think three of the five valve ball ends on my horn click obnoxiously. I can hear them clicking and I can definitely see WHY they're clicking if I stop the valve from rotating. There's lots of play in them, and in one of them it's enough that Hetman Bearing & Linkage doesn't help.

The Hetman lube made specifically just for ball joints is very viscous/thick/sticky, might help more: http://www.dillonmusic.com/HeleoCart/Pr ... ET-15.aspx

Eric "Hetman fan" L.

[MaryAnn]

3. The linkage shall not allow detectable play. (This could be refined to limit play to some acceptably small number.)

Oh, this one is my favorite!! I can think of a couple of tuba players whose linkages I really, really wish would allow no play. And if they are allowed to play, they should be limited to a very small number, maybe a few notes per concert.

MA

[SplatterTone]

A lube well known to gun owners (and, I think, the U.S.M.C.) is CLP (cleaner lubricant protectant) by Breakfree. It goes through a curing period after it is applied. I think it will provide some loose linkage filler properties.

But if the rubber bumpers are done bumped out, I'd fix that first.

[iiipopes]

Get the bumpers checked and refitted as necessary, get the linkage aligned and adjusted as necessary, and Roger Lewis is a fan of 3-in-1 oil for the linkage and sewing machine oil for the rotor bearings. Works for me -- quieted down my 37 year old "S" arm linkage, and I can get a large bottle of both at WallyWorld for the price of a 1 oz bottle of Hetman's.