 The Clarinet BBoard
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Author: clarimad
Date: 2010-05-13 06:32
Any tips or ideas on how to remove really rusted in rod screws?
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Author: clarnibass
Date: 2010-05-13 08:39
I found a long reply to this that I wrote some time ago, here it is again with some updates since I wrote it:
First is to verify if the stuck screw is a rod screw or a pivot screw. If you are not sure what is the difference, see this article http://www.saxontheweb.net/vbulletin/content.php?150-Saxophone-keywork-reference-for-technical-terms it is about saxophone keys but this is the same on a clarinet.
For a rod screw, first check if it is stuck inside the key or inside the post (or both). If the key can move, you check by looking if the rod screw moves with the key when you press it and let it return. If they move together, it is stuck in the key, if not, it is stuck in one (or both) of the posts. More often it is stuck in the key.
After you identify where it is stuck, use penetrating oil - and very important - use heat. Usually you can use a flame for this even on a wood or a plastic clarinet. Especially with plastic, you really have to be careful, and maybe better to use something like a Weller soldering gun, for example http://www.elexp.com/solder/d550.jpg then cut the tip off and touch with both tips on the part you want to heat (the part e.g. a key, a post, etc. will conduct it and will heat much faster this way).
You have to make the penetrating oil hot enough until you see it bubbles and/or vapours. You need to do this repeatedly, let's say several times a day and also wait to let it penetrate. I've never had a stuck screw take more than a day using this method but I know it can take a few days or more sometimes.
VERY important: You MUST use EXCELLENT screwdrivers! They must have a very good handle, a strong and sharp tip that fits the slot and long enough shaft for alignment. You also need to press down while you are turning.
If you see you are beginning to wreck the slot then stop imediately! You need to repeat more with the penetraing oil & heat. I would do this for at least 2-3 days, several times a day, before resorting to other methods. Also worth it to try to use the screwdriver while the key is hot.
If you already wrecked the slot (or it was already wrecked before) then it might be too late to do anything with a screwdriver anyway. In this situation I usually re-cut a slot with a micromotor while the screw is still stuck inside the key. But maybe you don't have the tools for this (most likely impossible to do with a dremel or flexible shaft tool).
If all else fails then a last resort is to cut the key right next to the post. But before doing it you should check how it would help i.e. would you be able to remove the key, remove the posts, etc. It might help you since you can hold some part in a vise, etc. or try to tap out a part that is stuck in a post. This method of cutting is mainly for keys with rod screws, less for pivot screws.
After cutting a key, even when using a VERY thin saw (I use an extremely thin cutting wheel on the micromotor) you'd have to repair the small gap of the key now causing free play.
After removing the key, if the rod is still stuck inside you have several methods. First try to tap it out using a similar piece of steel against it. You can continue to add penetrating oil and heat more drastically. Might help to grind some of the stuck rod off inside the tube to allow the other piece not to slip when you tap. If you managed to remove it by cutting the threaded end of the rod, you might be able to grab the sticking slot end with a vise or patent pliers and remove it this way.
As a last resort you can use alum, which will work eventually but is extremely slow. You need to mix it with water and heat it, then just put the part inside. It doesn't have to boil but it needs to be pretty hot. This will disolve steel but not the metals keys and posts are made from like brass, copper, etc. This takes a VERY long time. For a very short pivot screw, a few hours. A rod screw, about 3cm long, with only enterenace for the alum from the sides, it can take at least a few days. I only ever had to use alum twice. This is a brief explanation, if you are really interested in using alum then there are severla more critical things to know.
There are probably more ideas and issues that I forgot. The problem with this and many other repairs is that a lot of times they don't go exactly as you planned and during the repair you find more problems that you need other strategies to deal with.
Post Edited (2010-05-14 03:25)
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Author: tictactux ★2017
Date: 2010-05-13 10:14
One word about unscrewing stuck or sticky rods:
Instead of turning the screwdriver alone, keep the screwdriver in a steady position (this is a lot easier) and operate the key arm/lever/whatever, then loosen the hold on the screwdriver and turn the whole key/tube/rod/screw assembly back, fix the screwdriver and turn the key tube again. Wiggle like that till the screw is free.
The risk of slipping away with the screwdriver is a lot smaller that way, and you only have to overcome the friction in the key tube (and not the two posts as well). This works, of course, only if the friction within the tube is bigger than the friction at the posts. (cf Nitai's third paragraph "For a rod screw (...)")
The screw heads will be thankful for this gentler kind of treatment.
--
Ben
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Author: classic10
Date: 2010-05-29 21:00
Will the use of Alum harm the finish of silver clarinets? I have a Silva-Bet and I'm on the "Last resort" mode and I was wondering if I could use Alum to solve the problem.
Post Edited (2010-05-29 21:00)
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Author: tictactux ★2017
Date: 2010-05-29 21:27
How would "unsolder the culprit post" score in that competition?
I'm just idly thinking....
--
Ben
Post Edited (2010-05-29 22:13)
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Author: classic10
Date: 2010-05-29 22:07
I think from 0 to 10 it scores a solid "0" in the best solution scale. :-)
Unsoldering the post will most certainly harm the finish. That's why I was wondering if Alum would be a good solution on a silver clarinet.
I'm afraid to try using alum and the whole thing melts or the silver plating peels off. That would be tragic.
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