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Monks of Low Brass, I have a question.
I typically always find my answers to my questions by using the search function, as such I rarely have anything to contribute. But my curiosity about the benefit/ difference of Rose Brass Tubas (Cerveny 781) vs. a Yellow brass horn will have to wait for now.

My St. Pete is giving me trouble. I just had all four rotors lapped and that smoothed them out quite a bit, but this first rotor has always been noisy. In the video, I am not holding it down, it is sticking. This is a new development. I have oiled them internally and used rotor oil on the top and bottom bearings. Therefore I ask the following:

• Can anything be learned from the video?
• Should I have take it back to the repair shop?
• Should I just get a new rotor?

http://youtu.be/oAjsCEtdtnw
I appreciate any and all help and suggestions and thank you for your time.

David

When I purchased the tuba (sight unseen) the pictures were not specific enough and I should have been more specific. The local repair guy did a wonderful job getting it into running order. He replaced the bottom bow, and did a ton of work. Below is a picture of the valves that I took for insurance purposes a few minutes after unboxing it. The paddles are bent and you can see that the fourth rotor also has a bent shaft (as did the first rotor but you can't see it in the picture.) He adjusted the paddles and even turned them in to better fit my hand. For the last few months it has worked just fine, but recently the first rotor started acting up again. argh.

First... fix the bent stems. Make sure whoever does the work properly seats the rear bearing plates. I see lots of problems relative to badly assembled rotors. A F horn player was in the shop earlier this week with the complaint that his rotors were 'moving up and down'. The last tech who did the assembly work (I know it wasn't me because I don't use the crappy Yamaha rotor string) did not seat the rear bearing plates properly. If this stuff isn't put together right... the clearances between the rotor body and the housing will not be correct.

The rotors were LAPPED?

Any possibility that has now screwed things up further?

Also: I had a Cerveny 781 for about two decades. It was a very good BBb tuba with a wonderful sound. It was also a dent magnet that I was constantly paranoid about. It was also beautiful. I don't believe I would buy another red brass horn (at least one any larger than a flugelhorn ).

ghmerrill wrote:The rotors were LAPPED?

Any possibility that has now screwed things up further?

Goodgigs already covered this. Lapping is not a cure for a rotor that has been operating well in the past. There should be no contact between the outside periphery of the rotor and the inside of the casing if the bearings are fit correctly.

I really appreciate you guys taking the time. I will have a conversation with my local guy and discuss the various options you guys have brought up. The fourth rotor was the worst, and he has that one running smooth. I wonder if the first rotor just didn't get enough attention. There was a lot going on with this horn at the time.
Good times, good times.