Good way to shim the smallest ring

Gheorghe

While working on my top joint tenon last night, I discovered that that ring is loose - I was able to pull it off easily. When I overhauled my taragot last year, I shimmed all other rings with fabric. The way I did it, I stretched the fabric over the joint and hammered the ring on. Then I cut off the left over fabric. I did not do this with the last ring, as it looked to be on pretty solid, and I couldn't use the same technique (due to the tenon being in the way :) ). I turns out that ring was only glued on, with only some threads "symbolically" wrapped underneath. I think the heater I was using yesterday in the workshop helped undo that glue - I think it was pretty much hide glue.

Anyway, I was thinking about just wrapping some thread around the joint and hammering the ring on - enough thread for a snug fit.

Any other ideas/preferences?

George
 
I had to run and look at my taragoto to see what you were referring to. On mine I tightened the ring temporarily using masking tape underneath. The tech I trained with uses cloth on loose clarinet tenons, generally black silk. There is also a ring shrinking tool that can be used to decrease the ring's diameter.

I suppose you could cut a circular hole in the cloth for the tenon to fit through and then force the ring over the cloth and cut away the excess. Come to think of it, that may be the way I end up doing my top tenon. If one has a lathe and a way to center the joint, it would also be possible to build up the area under the ring using wood dust and cyanoacrilate and then turn it down to the proper dimension for the ring to fit snugly.

All of the lower rings on my taragoto were so loose that I have had to cut out a portion using a jeweler's saw and then silver solder (braze) the parts together. The bell ring was held in place using three small nails, and it is scheduled to be cut and downsized like the others.
 
I don't really know tárogatós much, but I'm guessing this is similar to clarinet metal socket rings? If that's true, I prefer to tighten them by gluing them with shellac. Here is why.

I've glued more than a few rings with shellac, in places where temperature can vary from around 0 to 40 (C) and humidity varies from my very dry city to the very humid city I often go to with my clarinets. I've never had problems. I have one on my own clarinet that was very presistantly loose in the winter (relatively tight in the summer) and it hasn't moved for more than three years. It is a good and stable method. Same for others I repaired using this method.

Dried shellac is hard and offers very good support for the ring. You could also use a type of other heat melting glue, but those are slightly softer and more flexible, so offer less support. Shellacs can vary in how brittle they are, so a very brittle type is not as good. Some claim the shellac is too hard and solid so it will crush when the ring tightens, but after a lot of experience with this method, this doesn't happen. For example I never have any issue with my own shellaced ring.

So in short, IME shellac doesn't have the issues that are sometimes suggested it would have.

As far as advantages over other methods, IMO there are several.

With shellac, the exact amount of "shim" is put between the ring and the body. Both the ring and body are probably not 100% exactly round. Putting a "fixed" thickness of shim like paper, fabric, etc. might not be the best all around the ring. It might make some areas tight but leave other areas less supported. Shellac is like an automatic perfect thickness shim. In reality, there is noreal way to know how much this matters, but there is no disadvantage from using the best thickness shim. I have seen the other methods for shimming slightly distort sockets and they might not support the body in a way that would necessarily help preveting cracks.

As far as physically reduce the size of the ring (there is a tool that does that), IMO it has the same disadvantage as above. It is also harder to remove and change again if needed, for the example if the player moved to a different area. With the shellac method, it's easy to remove the ring and re-tighten it again in a different area if needed.

Similarly to the other method, it is a fast repair that can be done on the spot and it doesn't require any expensive or special tools (unlike the ring press) so it's an inexpensive repair too. Basically, IME no disadvantages at all, only advantages.
 
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Thanks for the info everyone. Had I read it earlier, I would have probably chosen the shellac method. But as I tend to rush into things, I took care of it last night.

I ended up using my well-tested method of using fabric afterall. I stretched it over the tenon (like a tent) and tapped the ring on, then cutting off the excess. It worked very well, and none of that is permanent either. My intuition tells me that that particular section is very unlikely to crack anyway and the ring might be decorative more than anything else. I reinforced the MPC tenon right above the ring with thread and superglue before I installed cork in it, so I'm very confident about the stability of that whole section.

George
 
Nitai, are you referring to the type of heat melt shellac that is used to install pads. If so I am having a hard time visualizing how that would be applied under a clarinet ring on a wooden clarinet body. I am aware that one can take powdered shellac and mix with alcohol to make a paste that hardens when the alcohol evaporates. Maybe this is what you are referring to.

I disagree somewhat with your idea that a tenon that is not perfectly round does not work well with a shim that is the same thickness all the way around. My thinking is that the metal ring is flexible enough to conform to the shape of the tenon plus the shim material when there is a snug fit thereby eliminating any gaps or loose sections.

As far as tight rings preventing cracks in wooden joints, most of the techs I have spoken with on the subject say that they do not. An instrument subjected to an extreme humidity change will develop a crack, ring or no ring. The real purpose of the rings are: (1) decorative, (2) to protect the edge of the joint or bell, (3) to serve as a gauge to tell the tech when the wood has begun to shrink. Under this line of reasoning, the only reason we tighten rings is to keep them from falling off. : )
 
Since I have some experience with luthiery (I built a double bass for myself), my first concern with the rings was seasonal wood movement. I imagine this is the main reason why rings come loose in the first place. The idea of using fabric was attractive to me because some movement is possible. I figured it would be unlikely to have an overly tight fit when fabric is used.

Of course the reason hide glue is used in luthiery is the fact that it acts as a safety valve - when something goes due to seasonal changes, it's better that that something is the glue joint, and not the wood itself (cracks).

George
 
John, yes, it is heat melting stick shellac. Not necessarily the same that I use for pads, but sometimes it is. BTW this is another method I learned from Gordon Palmer. You heat the ring and smear shellac relatively evenly all around the inside of it. Put it (while still hot so shellac is soft to accomodate) in its place and clean any extra oozing out. It's pretty simple once you try it a couple of times and it is fast too.

I never meant that if it's not perfectly round it won't work well with a shim (a shim other than shellac that is). I just just explained some issues that are possible and worth considering. If a ring is not completely round and flexes over the not completely round wood, even if it can flex to shape, it can press against some areas more than others. It can also be too tight. It will just feel tight but not real way to know if it's too much. There is no feel for this, since even if it's very tight and difficult it can be fine, or not. The thing is, with the shellac you get the exact amount of shim.

I agree that the rings don't prevent cracks. If that was true then the end of the joints with tight rings would never crack. But they do help in preventing cracks. It is not uncommon to get a crack near a socket ring and find the ring was loose. I also think the good support all around is just better.

Basically, I see no reason not to use shellac and use a solid shim instead. I see no advantage, but only potential disadvantages. The shellac method is pretty much as fast, it lasts, it offers the best support all around evenly, it is easy to do and it is easily reversable if needed. Why use a solid shim instead (for someone who has shellac)?
If someone wants to do this at home and doesn't have any shellac, yes, they can use a solid shim and it would probably be ok.
 
Thanks for the clarification. Tell me what do you use for the clean up for the heated shellac that oozes out of the end(s)?
 
I usually start by feeling how loose the ring is and eyeing/guessing how much shellac to put, so there is the least cleanup necessary. This isn't specific at all. If the ring is just possible to remove by hand, I put just the smallest amount to cover the entire inside of the ring. If it's signficantly loose e.g. easily removed or even falls on its own, I put more shellac. After I glue it I mostly use a sharpened perspex rod to clean the extra shellac. If there are some bits left that are hard or impossible to remove this way, I use an ear bud with just enough alcohol soaked to only remove the extra shellac (and not drip everywhere, etc.).
 
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