 The Clarinet BBoard
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Author: kdk
Date: 2018-08-16 04:37
A student came to tonight's lesson with the top two r.h. trill keys completely jammed. The top pad cup was off center and may or may not have been covering the hole. I quickly realized that one of the sides of the saddle guide the two keys rest in was bent inward and was pressing on the keys, pushing them off line and keeping them from moving. Once I got the trill keys off the instrument (the pivot rod was also hard to move because the keys were at an angle), I tried to bend the side back to being straight. Although I was a little nervous that the piece might shear off from metal fatigue, I tried to nudge it back gently with a small round-nose plier. I was a little surprised when the piece, rather than shearing, actually snapped off. Looking at the broken piece and the spot on the saddle where it broke off, I strongly suspect that the whole thing isn't metal at all, but plastic. I'd need stronger magnification than my reading glasses to be sure.
Could that be the case? Is Buffet making hardware on their sub-R13 models out of plastic? The way it snapped off just didn't feel like metal gradually weakening and shearing.
The two keys are now, of course, moving freely, the pivot screw slid and screwed back into place with no real effort, and the trill keys seem perfectly stable even with one side of the guide missing. Is there likely to be a problem over time with just leaving it that way? I suppose I can probably get a part from my repairman - he may have a cadaver E-12 or two in the shop, or maybe one from an R-13 would fit. But I'm not sure if it matters. I've never had one of those break off before.
Opinions from the repair people here?
Karl
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Author: clarnibass
Date: 2018-08-16 09:13
Is it a newer E12F? Or some kind of older E12?
I don't remember noticing anything strange about the trill key guide and don't think it is plastic, but it's possible. They have made plastic socket rings for some models which tended to break (and actually gave less support than simply a one piece section).
If it is plastic, it's unlikely to bend that way, but it's possible, in particular if it cracked from the knock, so actually much less of the part was holding it when you bent it back.
Brass or nickel-silver rarely bends and then breaks like that, but it's still possible (unlikely as it is) that it was just on the verge of work hardening enough to cause it.
Another possibility is that it's made of the dreaded ZAMAK. Buffet has been using it for thumb rest parts, making them impossible to repair when their flawed design causes them to stop working.
If it's a copper alloy then there's a good chance you could tell between that and plastic by weight.
You could check with a magnet, which won't necessarily tell you anything, but I think some ZAMAK is magnetic... or not (don't remember).
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Author: Tony F
Date: 2018-08-16 11:38
MAZAK was used by B & H at one time for keywork. It's based on zinc, so it's probably not magnetic.
Tony F.
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Author: Chris P
Date: 2018-08-16 14:56
They have been using metal coated plastic trill guides on the student level Buffets for a fair while now. They're glued in, so can't be removed easily without risk of them breaking.
Former oboe finisher
Howarth of London
1998 - 2010
The opinions I express are my own.
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Author: kdk
Date: 2018-08-16 17:02
This one seemed to have attached by a screw into the instrument body. I didn't try to take the guide off, but I think I could have just unscrewed it.
FWIW, this is an E12F.
Karl
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Author: Chris P
Date: 2018-08-16 20:35
That could be a zinc alloy casting like the thumbrest if it's held in with a wood screw rather than having its own thread - I've only seen the one E12F and that was around three years back.
Former oboe finisher
Howarth of London
1998 - 2010
The opinions I express are my own.
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Author: kdk
Date: 2018-08-16 21:10
So, I always heard as a kid that cast keys tend to be brittle and not very malleable, which might explain the way the piece snapped off. Is that a true characteristic of cast metal parts?
Karl
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Author: Chris P
Date: 2018-08-17 00:03
It depends on the alloy used - keywork and key parts are often cast from brass, bronze and nickel silver, so they're as durable as keywork made by hand and more consistent (but still have to be mounted and finished by hand).
Other alloys like Mazak and other zinc alloys have a much lower melting point and will cast with a lot of detail (think Matchbox, Corgi or Dinky cars), but the alloy isn't as strong as brass, bronze or nickel silver and the other disadvantage is they can't be repaired as easily.
B&H and some other makers used die cast Mazak keywork on their low end models to make them affordable and offered replacement keys for any that broke rather than repairing them.
Former oboe finisher
Howarth of London
1998 - 2010
The opinions I express are my own.
Post Edited (2018-08-17 00:08)
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Author: clarnibass
Date: 2018-08-17 09:03
>> MAZAK was used by B & H at one time for keywork. It's based on zinc, so it's probably not magnetic. <<
I've seen only a couple of those and never checked if it was magnetic... but a few machine parts that were supposedly made of ZAMAK/MAZAK were magnetic... but maybe it was a different alloy with other things in it.
>> FWIW, this is an E12F. <<
I see more than a few of those, they are pretty popular here now, but I've never checked anything about the trill key guide. It might be the same terrible material Chris mentioned they use for the thumb rest.
I'll check what I can check next time I see one.
>> So, I always heard as a kid that cast keys tend to be brittle and not very malleable, which might explain the way the piece snapped off. Is that a true characteristic of cast metal parts? <<
Casting just refers to the method used to make them. Cast brass or nickel-silver keys might make them about as soft as they get, I'm not an expert but it is essentially getting them hotter than even annealing heat (since it's liquid). Maybe something about the casting causes a difference from annealing? Not sure. The specific alloy of brass or nickel silver can make a difference.
Copper alloys parts can be annealed after casting anyway, which would make them as soft as they can be (if they weren't already). So keys being cast or not basically means nothing to how soft or hard they are.
ZAMAK/MAZAK is more brittle in general and I guess specific alloy can vary too. I think this alloy is used mostly (or only?) for cast parts, as a lower cost material and method for mass production.
Copper alloys work harden which happens for cold forged keys (whic some clarinets have) and also for keys that are mostly cut to shape and then pressed (kind of similar to forging but less work hardening).
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Author: Chris P
Date: 2018-08-19 19:16
I just had a look at the scrap E11F top joint I have and the trill key guide on that is held in with a single wood screw on the top side.
I unscrewed it and had a closer look and it's made from cast metal as it has a very feint '1' in relief on the underside.
If the exposed base metal on the broken one you have has a grey appearance like lead or tin, then it's a zinc alloy casting. If you have a replacement, then heat the broken one up and if it melts and leaves an empty shell of plating, then it's definitely zinc alloy.
Former oboe finisher
Howarth of London
1998 - 2010
The opinions I express are my own.
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Author: kdk
Date: 2018-08-19 19:25
I have a replacement on order from Buffet through my regular repairman. But your description matches very much what I saw. Thanks for the information. I wonder if it *were* plastic whether it would have bent on whatever impact caused the damage. The student doesn't know how it happened.
Karl
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Author: Chris P
Date: 2018-08-19 22:04
I think if it was plastic, then it would've snapped clean off.
The B12 I've seen with the broken one was black plastic and metal coated and was glued into the top joint, so not all that easy to replace. Gluing them in place on a plastic clarinet is the same idiotic idea as spot welding fixtures and fittings to sax bodies as Selmer have been doing on their saxes as it makes removal and replacement a nightmare.
At least with them being secured with a wood screw (and fortunately Selmer have done on their clarinets), they're easy to remove when you have to.
Former oboe finisher
Howarth of London
1998 - 2010
The opinions I express are my own.
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