 The Clarinet BBoard
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Author: BbMajorBoy
Date: 2014-09-13 22:12
I have had my 1986 R13 back from overhaul for about a week. In that time, I am noticing that screws particularly on the thumb key and trill keys. I am wondering if this is going to die down or if it is going to get worse? Is it something that could be fixed easily by a tech or something that is detrimental.
Any advice would be great.
Leonard Bernstein: "To achieve great things, two things are needed; a plan, and not quite enough time."
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Author: Ken Shaw ★2017
Date: 2014-09-13 22:29
Please post photos so we can see what the problem is.
Ken Shaw
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Author: BbMajorBoy
Date: 2014-09-13 22:38
Sorry, after reading my post, I realise that it is really vague.
Basically the screws are working themselves loose.
Leonard Bernstein: "To achieve great things, two things are needed; a plan, and not quite enough time."
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Author: Chris P
Date: 2014-09-13 22:41
Loose fitting screws in their respective key barrels can be tightened by swaging the key barrels with the screws fitted in the barrels, then the ends of the key barrels fraised back to fit between the pillars as swaging not only reduces the diameter but also lengthens the key barrels.
The trill keys are a bit of a nightmare due to the telescopic key barrel (the lower trill key having the larger diameter key barrel that telescopes onto the top trill key barrel), so both will have to be swaged to achieve a good fit on the screw, between the pillars and both key barrels will have to fit well without binding nor the lower trill key wobbling about like anything.
If the screws are loose in the pillars, then the best remedy is to fit oversized screws which involves reaming out the key barrels so they fit and making sure the slotted ends are a good tight fit in the pillar heads. In some cases the pillar heads can be filled in (soldering brass or nickel tubing into them) then reamed out to the correct diameter of the rod screw so it's a tight fit.
If you've got a combination of worn pillar holes, worn screws and worn key barrels, then it's best and much easier to have oversized screws fitted.
Former oboe finisher
Howarth of London
1998 - 2010
The opinions I express are my own.
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Author: BbMajorBoy
Date: 2014-09-13 22:47
Should this have been included in the overhaul, I may be over exaggerating it but if I am not, surely they would've done something or told me about it?
Leonard Bernstein: "To achieve great things, two things are needed; a plan, and not quite enough time."
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Author: Paul Aviles
Date: 2014-09-13 23:12
Well, my first guess is that the tech may have inadvertently NOT tightened the rods enough. If you have already tightened them back in, and they are still working themselves out that leads to my second guess: perhaps the tech did not lubricate those rods before putting them back in. In that case, simply completely unscrew the rods (until you feel/here that dull 'click'), remove them, add some key oil (preferably heavy weight), put them back in and screw them in firmly.
This should solve any problems of the rods backing out.
The swaging (pronounced "swedging") and fraising is great to get the key action as smooth as possible but in my mind a key that is slightly 'wobbly' still shouldn't make the rod back out.
............Paul Aviles
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Author: Chris P
Date: 2014-09-13 23:15
It's an extra cost on top of the cost of an overhaul to fit new screws, but swaging keys should be included in the cost of an overhaul.
If a clarinet needs replacement screws due to excessive wear, then this will be diagnosed fairly early on and the work shouldn't go ahead until the owner has been informed of the extra cost and they agree to it.
Former oboe finisher
Howarth of London
1998 - 2010
The opinions I express are my own.
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Author: kdk
Date: 2014-09-14 02:28
Chris, I'm confused about why you would want to reduce the diameter of the key barrel if the screws are working out. Isn't that a sign the screw is binding inside the barrel already? Wouldn't tightening the fit make the binding worse? Would play between the screw and the barrel (if the screw were too loose a fit) cause the screw to work outward, assuming it was tightened firmly into the thread? I would have thought a loose fit would cause lost motion in the key, but I'm surprised it would cause the screw to back out.
You know more about this than I do, so I'm clearly missing something.
Karl
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Author: Chris P
Date: 2014-09-14 02:56
You're reducing the diameter of the key barrel through swaging to make it a snug fit on the rod screw.
But that's irrelevant now as I just read the screws are working themselves loose.
If the screws are backing themselves out, then they haven't been fitted properly or haven't been tightened up enough.
Former oboe finisher
Howarth of London
1998 - 2010
The opinions I express are my own.
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Author: tictactux ★2017
Date: 2014-09-14 03:17
some types of pivot screws (eg headless, conical tip, bell side) are more keen on working themselves loose than others.
A rather simple method of stopping this unruly behaviour is to apply the weakest variety of thread locking compound (eg Loctite) to the culprit screw.
Of course, this is no remedy against ill-fitted screws, but an economical alternative to reconditioning worn post threads.
--
Ben
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Author: Ken Shaw ★2017
Date: 2014-09-14 05:40
Try easy (and easily reversible) things first. Tighten each screw and then put a dab of clear nail polish over it. If that's not enough, try non-permanent Loctite.
If that works, here's no need to bend/shrink/swage the metal parts.
Ken Shaw
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Author: GLHopkins
Date: 2014-09-14 06:55
I'd suspect they weren't tightened properly in the shop. Take it back and let them do what's needed.
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Author: wanabe
Date: 2014-09-14 08:30
If the screws were backing out of my newly overhauled R13, I wouldn't give a tinkers dam about why they were backing out. I would take it back to the technician and demand that he give me back an overhauled clarinet like he promised.
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Author: clarnibass
Date: 2014-09-14 08:44
In most cases swedging is unrelated to screws that are working themselves out. In at least 99% of the cases it just means the screws weren't tightened hard enough.
However, sometimes screws cause binding when they are tightened and instead of dealing with this problem they are just left a little less tightened, which can cause the problem you have.
Like others suggested, first try to tighten them completely and see if you have a problem (key binding). It's sometimes hard to tell because a spring might overcome slight binding, so I check for binding without the spring, but this might mean you need to remove keys, etc.
It's (very) rare but it can even happen that a correct fitting screw will gradually come out even when completely tightened.
Generally I would say the problem you have shouldn't happen after an overhaul. In contrast to Chris, I would say replacing screws is alo a part of an overhaul, if it's necessary. Basically from a certain amount of repairs I would say an overhaul is an overhaul based on the condition of the clarinet after repairs. It's entirely possible to leave some issues if this is agreed by the owner and repairer.
If tightening the screws yourself doesn't help (or causes an issue) then you can take the clarinet back to explain the problem.
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Author: BobD
Date: 2014-09-15 14:12
I'd hate to think that the Tech. didn't keep track of the rod screws' original locations. Being a '86 horn the screw diameters might not all be identical.
Bob Draznik
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Author: D Dow
Date: 2014-09-17 05:27
my father was an excellent machinist and would have much to say..however, I suspect the key that houses the screw may be the cause of the screw coming out..if the walls of the housing are uneven this could be cause for a problem..Chris P or a good tech with the instrument could repair with ease if they could observe the issue in person.
David Dow
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Author: Chris P
Date: 2014-09-17 16:04
If the screw or the key barrel is slightly bent, that can increase the friction between the screw and key barrel causing the screw to back itself out. If a key binds up solid when the rod screw is screwed in tight, either there's a burr on the inside at the end of the key barrel or the pillar with the screw thread is out of alignment causing the rod screw to bow slightly.
Former oboe finisher
Howarth of London
1998 - 2010
The opinions I express are my own.
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