If the screw is broken off flush or below flush with the rotor, leave it for your repairman. Brass is soft and can get mangled easily by someone oversealously going after the screw with an easy-out.
On the other hand, if you're desperate and the screw remnant is sticking up above the rotor, you might try gently grabbing the stub with a small pair of long-nosed pliers (or even a hemostat) and seeing if it will loosen easily. If not, figure out how to live with it until your repair guy gets back.
Broken rotor screw
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Chuck(G)
- 6 valves
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- Joined: Fri Mar 19, 2004 12:48 am
- Location: Not out of the woods yet.
- Contact:
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Chuck(G)
- 6 valves
- Posts: 5676
- Joined: Fri Mar 19, 2004 12:48 am
- Location: Not out of the woods yet.
- Contact:
A stainless screw might be a good choice; I don't think there'd be much electrolytic corrosion difference between the standard nickel-plated brass variety and stainless.
Just don't overdo tightening it or crossthread it and you should be okay. A drop of machine oil on the threads before you insert it might help.
Just don't overdo tightening it or crossthread it and you should be okay. A drop of machine oil on the threads before you insert it might help.
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imperialbari
- 6 valves
- Posts: 7461
- Joined: Fri Mar 19, 2004 3:47 am
Regarding the steel screw I happen to disagree with my technologywise far superior friend Chuck.
The use of the harder steel screw will invite to a harder wear on the female threading of the rotor shaft. It is a problem when the screw breaks, but it is a bigger problem, if you have to cut a larger female threading inside the shaft.
My fairly large collection instruments has only once had the problem of yours. I also tried to solve a slack problem in a valve on my Conn 28K horn, and broke a screw-head off. Very silly done, as the tightening of the screw will not solve the problem. In my situation it was a matter of remounting the bottom plate with the other bearing in an optimal way.
Luckily I have repairmen within my closer circle of friends. One of them told, that the pro method of screw removing was to make a grip for a screwdriver. I went right home and found that the surface of the breaking point already provided such grip, so I could remove the screw shaft with a narrow screwdriver.
Already before that I had made the horn fully and securely useable by preventing the crank from falling off. The shaft end as well as the crank's inner profile are conical. If you jam the crank hard down on the bare shaft, the crank will sit securely. Probably for ever!
Which is not very desirable. So I took a plastic bag intended for freezing foods and cut off a small snip. The snip was used as kind of fitting between the rotor shaft and the crank. And the crank still sits securely after a decade. And still can be taken off without problems.
Another good repairman friend used to chime in at this point and tell, that you could use silicone tape. The snip from the freezing bag will do the same job just as well. And cheaper.
Your tuba will easily be reliably ready for your upcoming concert!
Klaus
The use of the harder steel screw will invite to a harder wear on the female threading of the rotor shaft. It is a problem when the screw breaks, but it is a bigger problem, if you have to cut a larger female threading inside the shaft.
My fairly large collection instruments has only once had the problem of yours. I also tried to solve a slack problem in a valve on my Conn 28K horn, and broke a screw-head off. Very silly done, as the tightening of the screw will not solve the problem. In my situation it was a matter of remounting the bottom plate with the other bearing in an optimal way.
Luckily I have repairmen within my closer circle of friends. One of them told, that the pro method of screw removing was to make a grip for a screwdriver. I went right home and found that the surface of the breaking point already provided such grip, so I could remove the screw shaft with a narrow screwdriver.
Already before that I had made the horn fully and securely useable by preventing the crank from falling off. The shaft end as well as the crank's inner profile are conical. If you jam the crank hard down on the bare shaft, the crank will sit securely. Probably for ever!
Which is not very desirable. So I took a plastic bag intended for freezing foods and cut off a small snip. The snip was used as kind of fitting between the rotor shaft and the crank. And the crank still sits securely after a decade. And still can be taken off without problems.
Another good repairman friend used to chime in at this point and tell, that you could use silicone tape. The snip from the freezing bag will do the same job just as well. And cheaper.
Your tuba will easily be reliably ready for your upcoming concert!
Klaus
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Chuck(G)
- 6 valves
- Posts: 5676
- Joined: Fri Mar 19, 2004 12:48 am
- Location: Not out of the woods yet.
- Contact:
What might make the most sense is to use a thumbscrew instead:
The problem is that people tend to overtighten things when they get a screwdriver in their hands. Which means that if the screw doesn't break off, the hole in the stop arm gets distorted. If you're worred about the screw loosening and dropping out, you can get some very light-grip Loctite threadlocker that will keep the screw from vibrating out, yet allow you to easily remove the screw when necessary.
The problem is that people tend to overtighten things when they get a screwdriver in their hands. Which means that if the screw doesn't break off, the hole in the stop arm gets distorted. If you're worred about the screw loosening and dropping out, you can get some very light-grip Loctite threadlocker that will keep the screw from vibrating out, yet allow you to easily remove the screw when necessary.