Top-Loaded Rotor Removal?

[ldine]

Could anyone explain how one could remove a fifth valve on a piston horn where the back of the rotor is blocked by tubing? Such as in the Eastman 836.

[Tabert]

The tool: Allied screwdriver handle with steel tapped to 3 x .5 with metal washer and clarinet body blank to function as a slide hammer.

https://www.facebook.com/chhite/videos/ ... 134350076/

[UDELBR]

Can also rebound it out: remove the retaining ring and hit the top of the rotor spindle straight down with a rawhide hammer. It should pop the plate off unless it's pretty stuck.

[Matt Walters]

You don't need any fancy tools to do this. Just some flat blade screw drivers.
For Eastman EBC-836:
1) Remove the two screws that hold the curved hand guard in place. Remove the guard and screws putting them in a safe container.
2) Loosen the big ring that holds the valve down into the casing about 1-1/2 turn. No more.
3) Use two larger flat blade screwdrivers with their flat blade under the stop arm but not resting on the strike (bumper) plate, lower the shaft of screw drivers down onto the ring you just loosened and then gently pry up to get a little lift or pop up of the entire rotor from inside the casing.
4) Back off the big ring another thread and repeat.
5) At this time loosen the center stop arm screw a thread or two and pry the stop arm up/loose to make sure it will come off the shaft once you get the whole rotor out.
6) Unscrew the big ring another turn and repeat.
7) When the ring is ALMOST unscrewed and you have been nudging the valve upwards in the casing, remove the ring and then grab the stop arm to lift the whole valve, strike plate, & stop arm assembly out of the casing.

It works on all stubborn top loader valves and you don't need a special tool with different threads for different valves.

Of course make sure you won't be pressing the screw driver handles down into the horn denting it when you do this. And again pay attention that where you place the screwdriver under the stop arm you aren't prying back down onto the strike plate and getting nowhere.

Hope this helps.

[ldine]

Will there usually be a guide on the plate for reassembly? I want to make sure the rotor alignment is correct after reassembly.

[Matt Walters]

Yes. There is a notch in the valve casing and a pin in the top bearing plate that fits into the casing notch. Align the rotor (trim the bumpers) by removing the main tuning slide and sighting down the Main t/s outer tube.

[joh_tuba]

Can also rebound it out: remove the retaining ring and hit the top of the rotor spindle straight down with a rawhide hammer. It should pop the plate off unless it's pretty stuck.

This method works great on the European produced top loading rotors because they don't have much up and down play.. the rebound is able to push the top plate off.

This method does not work on the Eastman tubas because there is too much up and down play for the rotor to rebound into the top plate. Less elegant solutions as described must be employed.

[UDELBR]

This method does not work on the Eastman tubas because there is too much up and down play for the rotor to rebound into the top plate. Less elegant solutions as described must be employed.

Ugh: I'm not a Chinese tuba-basher by any means, but if this is true, the potential for sloppy porting this suggests is reason enough to avoid this brand.

[Matt Walters]

Ugh: I'm not a Chinese tuba-basher by any means, but if this is true, the potential for sloppy porting this suggests is reason enough to avoid this brand.

I came up with my gentle (simulate a mouthpiece puller) technique working on German built rotors and found the $39,000 Yamayork to have the tightest top loading valves to remove with the Eastman valves behaving very similar to the Yamayork's. I've never run into an Eastman tuba having excess top to bottom motion in a rotor valve. Especially after I take them out, clean and reinstall with fresh oil prior to me shipping one out. I'll watch for up and down slop on the next virgin Eastman with a rotor valve.

[UDELBR]

I'll watch for up and down slop on the next virgin Eastman with a rotor valve.

You da man, Matt!

[joh_tuba]

FWIW, the up and down play is the only obvious mechanical deficiency I've found with Eastman. That and I personally would be uncomfortable owning a horn that so easily dents(not a comment on quality just their design decision)... but they are otherwise well made and designed and play nice.

[ldine]

FWIW, the up and down play is the only obvious mechanical deficiency I've found with Eastman. That and I personally would be uncomfortable owning a horn that so easily dents(not a comment on quality just their design decision)... but they are otherwise well made and designed and play nice.

Sorry to dig this up, but what is it about their design decision that causes them to dent easily? And what do others do that cause them to stand up to abuse better?

[Easy Mac]

I have heard that it has something to do with heat treatment. But all I know about heat treating brass is annealing, or softening it. I think hardening it is called tempering, and it involves heating and then quenching in water or oil.

Would this be why some horns are super thin b ut dent less easily. while some are thick but softer?