 The Clarinet BBoard
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Author: Anji
Date: 2001-06-10 12:17
So, as I slog through my dining room table workshop and invest in my repair education I note the mechanism on clarinets seems pretty crude.
Worse yet, the design seems unmodified from the earliest examples in my closet (ahem, in my scheduled repairs depot) to the 1980's vintage horns I have.
Any thoughts about a redesign?
Could there be an application for ceramics or sintering at the pivot points?
It seems that the steels (rod and bushing) are a vulnerable design.
I'm not thinking about the NXT design, or moving tone holes, just the mechanical parts. I just replaced my third low F# key on an R13 where the actuating tip was shorn off... a smooth delrin 'tip' taking the load is quiet, but soft.
anji
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Author: Jim
Date: 2001-06-11 05:38
Obviously, there are many hi-tech versions of pivots and bearings available today. The stresses and wear on these mechanisms are minute (they only travel a few degrees at a relatively slow speed after all) that I wonder if the increase in costs/ complexity in manufacture and repair would have any real benefit. The only advantage I can see would be to eliminate key oiling. Perhaps of benefit would be the use of stainless steel to eliminate the rust problem.
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Author: Gordon (NZ)
Date: 2001-06-11 15:03
The bearings will always lack perfection because they have to accomodate expansion/contraction of timber with humidity, and polymers with temperature.
A watchmaker here put ruby bearings on a clarinet. I don't think there was any advantage though.
What advantage are you thinking of with ceramics. Wear and rigidity are not a big problem.
Sintering of bushes is usually used to make the metal porous to keep lubricant supplied to a surface. This is not a big problem with clarinets.
Stainless steel is used on many models. I understand that the type of S/S with excellent corrosion resistance is a poor bearing material. The S/S used for clarinet pivots seems to be no more corrosion-resitant than high quality steel. Indeed it often seems less resistant but I don't know why.
I regard the pivot variations already used as highly successful for accurate, reliable, low friction mounting of keys with adjustment potential frequently incorporated. They are good when they are well made, but some are very poorly mane.
I agree that delrin tip is too weak. Any great accuracy of this particular linkage is limited by the need for the linkage point to ROTATE around the axis of the key as the key is operated. Either the lever needs a sloppy pivot or a sliding action must be accommodated at the linkage point, as is incorporated in the non-pin system.
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Author: Hiroshi
Date: 2001-06-12 07:07
Buffet adopted pivot screw with spring: It needs self-centering characteristics.
Ceramics is too brittle to use.
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Author: Gordon (NZ)
Date: 2001-06-12 12:06
In Selmer's saxophones the Super Action 80 series refers to spring loaded 'slugs' that the point pivot screw bear against. It so far seems a good idea to give lateral stability without fine adjustment of the seating of the pivot screws. Eventually corrosion jamming the slug could be a problem. They introduce more friction into the mechanism. Perhaps this is one reason that newer Selmer saxes have quite strong springing. (Another seems to be the pad stickiness introduced by a waterp;roffing treatment.)
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