 The Clarinet BBoard
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Author: rmr25
Date: 2004-04-12 23:22
Does anybody know an effective way to remove a severely rusted pivot screw from its post? I'm fearful of buggering the screwdriver slot.Bob
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Author: Synonymous Botch
Date: 2004-04-13 00:24
Ferree's makes a penetrating oil called "Corrosion Cracker" for this problem.
A small drop of Liquid Wrench at the pivot point, left to work overnight should help. If the other post can be reached, you may be better served to disassemble the entire key and remove the rusted post from the body.
What did your local tech say?
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Author: Bob A
Date: 2004-04-13 01:44
I just LOVE these answers that assume you have one within 50 miles.
"What did your local tech say?"
Bob A
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Author: Grabnerwg
Date: 2004-04-13 03:50
Liquid wrench and heat. Watch out, liquid wrench is very flammable!
Walter Grabner
www.clarinetxpress.com/repair.html
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Author: JMcAulay
Date: 2004-04-13 03:53
If you have post in hand (without the Clarinet body), you can dissolve the old steel screw (rusted, crossthreaded, whatever) with alum.
Search the archives; there has been some discussion on this in the past,
Regards,
John
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Author: BobD
Date: 2004-04-13 18:57
You are very correct in not wanting to bugger the slot. I say this having done it once and am still hoping to someday resolve the problem. Along with Walt's heat and Liquid Wrench.....plenty of patience.
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Author: rmr25
Date: 2004-04-13 20:29
Thanks, everyone, for the suggestions.
I apologize for making the classic error: NOT searching archives before posting. I did search there and found other tips.
I'm learning!
Bob
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Author: Gordon (NZ)
Date: 2004-04-14 11:47
"I just LOVE these answers that assume you have one within 50 miles.
'What did your local tech say?'"
Do you not have/use a courier service, or can't you trust it in USA? Here in my wee, small country, I receive work by courier from up to 100 to 800 miles away, at lest once per week.
I hope you found the info on:
- using heat
- see-sawing the key to get friction to work FOR you rather than against
- gripping the shaft by squeezing the hinge TUBE around it with an appropriate, specialised, non-damaging tool
- As a last resort, a process involving cutting through with a VERY thin blade, or drilling out the threaded end, and going on from there.
In my experience one of the most important things is a first class screw driver for the job - perfectly matched, sharp blade, special steel, long shaft, large diameter handle. I save my best ones exclusively for these jobs.
You really only get one decent chance before you begin wrecking of the slot such that every future attempt is LESS likely to succeed. In my view, for a very stuck screw, this is a job where both experience and the ideal tools (pretty expensive too) are essential.
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Author: BobD
Date: 2004-04-14 17:15
Once you have the correct screwdriver in the slot(and after having applied solvent and heat properly) it is important to put adequate pressure on the screwdriver in a longitudinal direction towards the slot as you attempt to twist it. It is frequently necessary to support the post to do this so you don't damage the anchoring of the post.
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Author: Gordon (NZ)
Date: 2004-04-14 22:45
... and it is often more successful to attempt to turn it while the pivot is hot.
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Author: rmr25
Date: 2004-04-15 00:11
Here's the end of this story.
Heat and solvent didn't do the job. So my last resort was to use a jeweler's saw (very fine blade) to cut a notch in the post and deep enough to re-establish the slot in the end of the screw. This gave enough purchase for the screwdriver blade to grip and remove the screw. The slot in the post is about 1mm deep and isn't too obvious. The final cosmetic fix, I suppose, is to replace the post. A second post had a seized rod with a diminished slot. This yielded to nothing, so I ended up splitting the head of the post with the jeweler's saw/screwdriver blade. Thence, I could grip the rod with needle nose pliers and remove it. That post obviously has to be replaced.
That's enough rust for this year! Thanks for all your help.
Bob
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Author: Gordon (NZ)
Date: 2004-04-15 08:53
I suppose the damage is done now, but splitting a post would never be necessary.
If you need to replace a post, that sounds like the beginning of an even more difficult story. Posts are drilled AFTER installation.
Regarding the one you cut, the cut could be filled with 95/5 tin/silver solder, which is low temp and maintains a bright appearance.
Personally, I don't think, cutting a post should EVER be necessary.
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Author: David Spiegelthal ★2017
Date: 2004-04-15 15:32
I disagree with Gordon, I've had to cut posts to remove rusted screws, though having a large supply of 'donor' clarinets and parts I've been fortunate to be able to discard the damaged posts and replace them with good ones from other clarinets. I don't have as fine a touch as Gordon (I'm inferring this from various previous discussions) so I probably resort to brute-force methods more often --- and I don't trust myself with using heat on or even near a clarinet, so that option is not one I would choose. The bottom line is of course (as in medicine), one should use the least invasive method available that gets the job done. I think Bob (rmr25) took exactly the right approach in the end.
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Author: BobD
Date: 2004-04-15 22:39
Heat applied with a soldering gun isn't too dangerous...
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Author: jbutler ★2017
Date: 2004-04-15 22:46
I only had to cut one post, but I did from the TOP, then separated the post above the pivot screw enough to break it loose from the threads. Removed the rusty pivot, squeezed the post back to position and soldered it on the top side and blended in. You could barely tell the post had been slit. This process would only work on pivots, not threaded steels.
jbutler
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Author: Gordon (NZ)
Date: 2004-04-15 22:55
Rather than destroy a post, that has been machined to fit to close tolerances on site, I would cut through the hinge tube and rod at one end, swing the key away, in the direction of unscrewing the other-end post, then unscrew the offending post, restore it OFF the instrument (punches can now be used), return it, make a new pivot rod, and swedge the tube back to a good fit between the posts.
That is pretty standard practice, I believe, but only needed in the very worst cases, such as what seems to be described.
Heat makes a HUGE difference to the effectiveness of penetrating fluids, and also softens binding residues from the additives of inappropriate key oils.
If I screw in an already-drilled replacement post, especially if I screw it in until it bottoms, then it is most unlikely that the hole accurately aligns with the hole in the other post.
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Author: Wayne Thompson
Date: 2004-04-18 23:09
Gordon, I have just this situation on my bench now. It is my first attempt at a total overhaul. Your advice sounds good. The slot in the rod was already messed up before I started, and with my efforts is now destroyed.
I was using WD-40 (a commercial product in the US) as a penetrating oil. Maybe that was why merely heat and force didn't work? Anyone have experience with this? I will for sure buy Ferree's product now, unless you all advise me that WD-40 is just as good.
My 1946 copy of Eric Brand's manual suggests his 'Special Screwdriver, RT 415'. Do any of you know a source for something like this? Gordon what is your source for really fine screwdrivers?
WT
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Author: jbutler ★2017
Date: 2004-04-19 01:52
Wayne,
WD40 isn't much good as far as I'm concerned. Your best bet is to go to your local sporting goods store or gunshop and get some nitro-solvent. Hoppes is the most common name brand I can think of at the moment. This along with a lot of patience (up to several days) and heat from a soldering gun with a split tip will usually do the trick. As per Gordon, there isn't a substitute for a good screw driver. Most of the ones found in hobby shops are junk. Unfortunately, the best screwdriver in the business that I've found, from Ed Kraus, is not available to the general public. You might see if a local tech or music store would order one for you however.
jbutler
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Author: Gordon (NZ)
Date: 2004-04-19 05:14
When the slot is wrecked, I use a very small dental burr, the width of a slot and create a new slot, working inside the post hole, without damaging the post.
I have not done comparative testing of penetrating fluids, but the gun shop suggestion is excellent. Specialist Engineers supplies will also have their favourites. My guess is that there are dozens of excellent penetrating fluids on the market. I certainly would not assume that Ferrees is the ultimate.
I agree about the screw drivers. Kraus are my favourites too.
You can view them at http://www.krausmusic.com/index.htm but note the policy statement. These are expensive screw drivers. Carefully measure the width of the slots you need them for. You probably need only one or two sizes. A longer screw driver, for some reason, is far better at getting out difficult screws.
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Author: Wayne Thompson
Date: 2004-04-20 02:31
Yes, thankyou! Kraus it is. Obviously, I am not NABIRT trained, but I do work for a music store. And I understand good tools. And approprate tools. We'll see what they'll do.
WT
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