 The Clarinet BBoard
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Author: Garth Libre
Date: 2012-08-13 23:49
About a week ago I moved the thumb rest of my Yamaha. The screws were not self tapping ones that came stock with the horn. I had a variety of very thin drill bits (two that were actually thinner than the screw shaft). I tried to get the screws in the holes but because the screws weren't pointed I sort of had to widen the top of the hole just a shade to get them started. Once I got them in they were very tough to screw in, so I waxed the threads. When I first screwed them in the thumb rest was in tightly. A few days later I noticed the rest was loose, so I tightened the screws again and again they screwed in with resistance. Later that day the rest a shade of wiggle returned. I don't want to tighten the screws again for fear that the holes will just get more noodled out. I don't want to move the rest because it's in the ideal position for me.
Question ... what do I put in those holes to make the threads catch and secure the rest? In other woodworking projects (furniture), I usually use white glue and toothpicks and then re-drill the holes or screw the screws back in with glue and toothpicks while the glue is still wet. I have no idea how the factory put those screws in because I must have an enormous selection of tiny drill bits and I surely was in the ball park when I choose the ones I went with.
Garth, 305-981-4705. garthlibre@yahoo.com
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Author: Chris P
Date: 2012-08-14 07:41
Normally thumbrest screws can be screwed directly into a pre-drilled hole in the body and that's them secure.
I moved the entire thumbrest assembly on a plastic Yamaha recently and used a 1.6mm drill (with a depth stop of 4mm) to drill the new holes, then simply screwed it in place.
Former oboe finisher
Howarth of London
1998 - 2010
The opinions I express are my own.
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Author: Campana
Date: 2012-08-14 12:01
I too have just changed the thumb rest to an adjustable one, which meant repositioning the holes, in grenadilla wood. I used a 1.5mm dia bit in a pillar drill. No problems, all went smoothly and accurately but only one hole is secure, in the other the threaded contour just crumbled away. Perhaps there are parts of grenadilla wood that are less able to hold a thread than others? I shall have to plug with a fibrousy soft wood, set in with white wood glue and screw in again.
You're right about getting these square ended screws started, what a pain.
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Author: Chris P
Date: 2012-08-14 12:05
If the grenadilla has crumbled, a drop of superglue in the drilled hole will soon sort that out.
Former oboe finisher
Howarth of London
1998 - 2010
The opinions I express are my own.
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Author: clarnibass
Date: 2012-08-14 13:12
Because screws often don't thread the wood that great a slightly bigger than optimal drill is sometimes needed and the screw can eventually be loose. This is the most likely cause for loose screws but it can be another reason too.
Regardless of type of screw, I prefer to take an identical screw or occasionally even the thumb rest screw itself and shape the end to be like a tap. When doing this, the "tap" has to be from the end to at least the beginning of where the biggest diameter of screw threads are. This cuts the threads much better in the hole, as opposed to the regular screw threads half squishing the wood.
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Author: Tony F
Date: 2012-08-14 14:43
If you take a fine jewellers file with a narrow wedge shape and carefully file a v-shaped notch in the first few threads of the square-ended screws they will act in the same way as self-tapping screws and will cut their own thread. If the hole has crumbled, just put a smear of either superglue or full strength araldite in the hole, and when cured redrill with a 1.5mm drill and then insert screws as prepared above.
Tony F.
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Author: Campana
Date: 2012-08-14 14:49
The original screws that were factory fitted on my B&H Edgeware were not wood screws. They were machined threads and the holes must have been tapped using proper engineers taps. I reckon that's the way to go.
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Author: Chris P
Date: 2012-08-14 15:45
While they're referred to as wood screws, they're not the same as, or a miniaturised version of the familiar self tapping wood screws you'd buy in a hardware shop. Some may be, but that's a very rare thing.
They're called wood screws simply for the fact they screw metal components directly into the wood (thumbrests, anchored pillars, key guides, socket ring straps, joint fittings, floor spike fittings, sling rings, etc.).
The wood screws used on woodwinds usually have a coarse parallel thread instead of a taper to them, so a pilot hole of the correct size for the screw must be used. Whether or not you need to tap the drilled hole depends on the screw - with nickel silver screws it's vitally important the hole is tapped as the screw would snap if screwed straight in.
Steel (mild and stainless) screws are by nature stronger, but care has to be taken the slots in the heads don't get mashed up or part of the head broken off. Some wood screws do narrow at the tip and some do have a pointed tip to them which makes it easier to get purchase when screwing them in without tapping the holes.
Former oboe finisher
Howarth of London
1998 - 2010
The opinions I express are my own.
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Author: Bennett ★2017
Date: 2012-08-14 18:10
You might try wood putty, aka plastic wood; available in any hardware store.
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Author: Chris P
Date: 2012-08-14 20:17
Superglue is better.
Former oboe finisher
Howarth of London
1998 - 2010
The opinions I express are my own.
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Author: vljenewein
Date: 2012-08-14 20:52
I had a post on a Boosey & Hawke Edgeware that was loose in the Grenadillia wood. I took it out and used J-B Weld Wood Epoxy. It mixes in 2 parts like the regular steel J-B Weld, but it's made for wood. Put a dab into the hole are after I threaded the post back in and left it along a day, it's as solid as the day it was drilled and tapped.
J-B Wood Weld
I found mine at Menard's. Probably can find at a lot of different hardware stores or woodworking stores like Woodcraft.
Vernon
Jenewein Duduks Manufacturing & Research
www.duduk.us American made Duduks
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Author: Garth Libre
Date: 2012-08-14 21:12
If you use JB Weld wood epoxy, will you ever be able to unscrew the thumbrest for some reason? Are you actually gluing the screw in the hole? I'd be worried it would never come out. Maybe I shouldn't be because I'm convinced the rest is in the perfect position, but what if I sell it?
Garth, 305-981-4705. garthlibre@yahoo.com
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Author: Campana
Date: 2012-08-14 21:32
Like Garth I sought a solution that allowed subsequent removal of the rest, if necessary. After the initial installation I ended up with one good fitting screw and one that wouldn't tighten, just turned and turned. It would only be a matter of time before a wobbly rest would undermine the good screw as well.
For better or for worse I removed both screws and stuck the thumb rest in place (perfectly aligned with the holes) with a rubber based general adhesive. I reckoned this would reduce any chance of looseness or movement putting a strain on the screws. When set and cured I inserted the screws, both set in the same adhesive.
It's rock solid but I reckon the choice of adhesive would allow subsequent dismantling.
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Author: Garth Libre
Date: 2012-08-15 01:55
What rubber based general adhesive is the one that worked for you?
Garth, 305-981-4705. garthlibre@yahoo.com
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Author: Campana
Date: 2012-08-15 07:21
I'm not sure what brand names are used in the U.S. but in the UK it would be the Evo Stick type of adhesive. The type that sticks rubber soles to shoes, plastic laminate sheeting to kitchen work tops etc. Like the double sided sticky pads that you can use to stick hooks on to bathroom tiling it grips well enough to do the job but it can be forced off when required.
p.s. I'm probably not technically correct when I said "rubber based". I really meant an adhesive that sets "rubbery"
Post Edited (2012-08-15 07:25)
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Author: Garth Libre
Date: 2012-08-15 10:30
That sounds like what we on the other side of the ocean call contact cement. It works by coating both surfaces and letting them dry, then placing them together for an instant bond. If that's the stuff then it poses an additional problem of getting the thumb rest perfectly lined up on the first shot. Usually repositioning is not possible afterwards. Also that kind of glue might not let you turn a screw in to a complete depth. it tends to bind up as soon as the two surfaces mate.
The other thing I think you might be talking about here is sold as floor tile glue. Now that stuff is amazingly bondy but always retains lots adhesive power with some minimum flex even years later. We do have a product that sticks shoe soles together called Barge. I was not aware that it might work on metal but I guess it sticks anything. It is applied wet, sets up slowly and always retains a rubbery stickiness, enough to hold shoe soles together through all those stresses. Of all the things I mentioned that one seems to match your method the best. Thanks.
Garth, 305-981-4705. garthlibre@yahoo.com
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Author: Chris P
Date: 2012-08-15 12:15
Contact cement or impact adhesives (Evo-Stik type) aren't ideal for glueing on thumbrests or 'curing' loose screws - they are used for glueing on key corks and tenon corks but apart from that, they don't have much use on woodwinds.
It's best for sticking things to other things with a relatively large surface area that aren't structural or will be put under a lot of stress - the surface area of a thumbplate base is far too small to be secured in place with Evo-Stik and sooner or later it will come adrift.
If a screw hole in a wooden instrument body has stripped, it's best filling in with something far more durable which is either superglue or epoxy, then drilling out and finally fitting the screw. Even if a wood screw has been bonded in epoxy or superglue, it can still be unscrewed.
In a severe case where the screw won't hold at all, the hole can be driled out larger and bushed (by superglueing in a grenadilla plug turned down to fit tightly), then made flush with the surrounding joint surface and polished, then drilled out so a wood screw (or pillar) can be screwed in again and hold the thumbrest on.
It's pretty easy to do and saves a lot of fart-arsing around with the wrong kinds of glue which will fail.
Former oboe finisher
Howarth of London
1998 - 2010
The opinions I express are my own.
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Author: Mark Charette
Date: 2012-08-15 12:52
Chris P wrote:
> In a severe case where the screw won't hold at all, the hole
> can be driled out larger and bushed (by superglueing in a
> grenadilla plug turned down to fit tightly), then made flush
> with the surrounding joint surface and polished, then drilled
> out so a wood screw (or pillar) can be screwed in again and
> hold the thumbrest on.
Essentially the same repair for a screw hole that has been bunged up in a door latch Make/get a plug, glue it in, cut off excess, make new hole. Carpenters and wood repair people have been doing this for at least since the screw was put into wood I'll wager.
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Author: Campana
Date: 2012-08-15 13:27
I dispute several of the criticisms made against the Evostick method. Firstly a thumbrest is normally attached without any adhesive, so the use of Evostick is an additional safeguard. While you could pull it off with brute force (the whole purpose of using this type of adhesive) the weight of the clarinet is hardly likely to cause much problem. Also, in my case I had one good screw...sorry, I'll rephrase that...I had one secure screw and one screw that was tight enough for the screw to follow the thread all the way in and out but jumped the thread with the final tightening torque. In my case the extra thickness of adhesive even made the screw accept the final tightening torque without jumping. It is now Rock solid.
If however the screw fits like a stick of rhubarb in a bowl of custard then of course plugging and re-drilling is justified.
Note to Garth. You can use guides, such as darning needles stuck in the screw holes to guide the thumbrest into position or in my case I positioned it early and let it cure in it's own time.
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Author: Chris P
Date: 2012-08-15 13:38
I'm only making criticisms against this use as it's not a long-term solution. No repairer in their right mind would ever use this method to fix a thumbrest back on, so it's best have the problem fixed and the thumbrest fitted back on properly than not at all.
If the thumbrest is only supported by one screw, sooner or later that one will loosen and you'll end up needing both screw holes bushed and the thumbrest refitted. If you've made a mess of glueing things on and that all needs cleaning up, then that will only add to the cost.
Best solution - get it fixed as soon as the problem arises and don't resort to temporary measures that may compromise things later on.
Would you drive your car around if one of the wheels was glued on instead of being bolted on?
Former oboe finisher
Howarth of London
1998 - 2010
The opinions I express are my own.
Post Edited (2012-08-15 13:47)
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Author: Campana
Date: 2012-08-15 14:08
I think the consequences of a failure between a car's wheel and a clarinet thumbrest could be considered slightly different.
It has been generally conceded that the screws supplied with a thumbrest are pretty useless at cutting their own thread. So what do you do...
1. Plug the hole and go through the whole paraphernalia again without any guarantee that this time you will be able to cut a decent thread.
2. As above but try to buy an engineers thread tap for an unidentified thread on a couple of existing screws.
3. Make the best of what you've achieved so far and make it work.
Of course, it all depends on the person, his objectives, what will make him satisified. An elderly person with failing eyesight will make a different choice to an OCD person or a professional repairer.
There are many ways to skin a cat. I've just given one option, which I didn't give until I did it myself and found out that it worked SUPERBLY.
Post Edited (2012-08-15 14:10)
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Author: Chris P
Date: 2012-08-15 14:53
I've fitted numerous thumbrests to the numerous new instruments I've finished (in wood, plastic and ebonite) as well as relocated many on wood and plastic instruments and also bushed ones on instruments that have had the threads stripped by DIY over-enthusiasts or have been ripped out through accident - so far I haven't had a single failure that I know of, so I must be doing something right.
So there's definitely something in having a thumbrest fitted properly than merely making do.
Former oboe finisher
Howarth of London
1998 - 2010
The opinions I express are my own.
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Author: shmuelyosef
Date: 2017-08-24 21:49
Just curious...do any of you treat plastic (e.g. ABS) or hard rubber clarinet thumbrest screws differently than wood clarinets?
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Author: Chris P
Date: 2017-08-24 23:22
Exactly the same as I do on wooden bodied instruments, but make sure you don't over torque the screws once the thumbrest is snugly in place as plastics are more liable to having the threads stripping.
Former oboe finisher
Howarth of London
1998 - 2010
The opinions I express are my own.
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Author: Matt74
Date: 2017-08-25 03:13
A good way to reuse holes in wood that have been stripped is to put something in the hole (like a few splinters of soft wood), or around the screw (like thread). This has the advantage of being quick, not altering the original, and not involving adhesive. There is no drilling. I like matchsticks.
You would have to be careful not to put too much in to avoid splitting on something small and hard like a clarinet, but soft wood squishes easily and holds very securely.
- Matthew Simington
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