Shop Talk: NEW BUFFET PIVOT SCREW DESIGN

*SHOP TALK ...* *mouthpieces, reeds, instruments, ligatures and this Shop Talk item by David Hite:*
A New Pivot Screw Design from Buffet

Standard
pivot screws The traditional pivot screw used on woodwind instruments has a tapered tip which allows it to be tightened into the end of the key hinge. Ideally, it should hold the key securely but not so tightly that it binds, restricting the free motion of the key. The screw must be adjusted to tighten precisely into the key so that it will eliminate any looseness or play in the action of the key hinge.
After the instrument is played for several years, the action of the keys causes slight wear on the screw and the key. This wear allows the key to wiggle from side to side and creates extra noise in the key action.
A repairman can correct this problem by deepening the screw seat in the post. The screw can then be tightened a quarter or half a turn more to advance it further into the end of the key, and the key will no longer wiggle. After this adjustment, the key will be secure in its action for another year or two of playing activity.

Problems
with traditional
design Problems maintaining this precise pivot screw / key hinge adjustment are common. If the seating in the post allows the pivot screw to tighten into the end of the key to the point of binding the hinge as it tightens into the post, the pivot screw must be backed out until the binding is relieved. This loosens the head of the screw in the post because it cannot be tightened against the seating in the post. The action of the key causes the pivot screw to move with the action of the key. Consequently, over a period of time, the screw will "back out" of the post.
A careful player will frequently check his instrument for loose screws, tightening them appropriately. Without this attention, the screw can totally unscrew itself from the post and drop away from the instrument. Unless the screw can be found and replaced, the player might be faced by an emergency of grand proportions. Worst case scenario, of course, is facing this situation just before going on stage for a concert or recital!
(In an emergency, I would suggest whittling down the end of a wooden match stick to approximate the shape of a pivot screw. Force it through the post and into the key. This bit of patchwork will suffice until the instrument can be taken to a repairman for screw replacement and adjustment.)

New Buffet
design
New Buffet screw Following extensive research and testing, Buffet-Crampon has devised a new type of pivot screw. This screw has a nylon sleeve just below the head and above the threads. (The post must be drilled and threaded differently to receive this screw design.) The screw can be adjusted for perfect hinging of the key, and later, as the hinge wears, it can be tightened as needed to maintain the perfect adjustment.
The nylon shoulder pivot screw has two advantages over the traditional design:
First, as described above, it keeps the screw perfectly secure in the post while allowing for further adjustment into the key hinge.

Second (... and this is a personal observation), it quiets the key noise -- that is, the "clank" of the key opening and closing. The nylon serves to dampen noise that may pass through the post into the instrument. It is my impression that the keys on instruments with the new screws are quieter even than optimally adjusted keys of the older design.

Use of the
new design Is it possible to replace the screws on older Buffet instruments with the new nylon sleeve screws?
François Kloc, the recently appointed technical advisor to Boosey & Hawkes Musical Instruments, Inc. here in the United States, informs us that this is not practical. The posts must be specially threaded and seated to receive this new screw, and consequently, the screw is not compatible with the posts on older clarinets. Conversely, the old design screws cannot be transferred to the newer instruments.
The new pivot screws can be found on all Buffet E-13 soprano clarinets beginning with serial number 111219 and all Buffet R-13 Bb and A clarinets beginning with serial number 426408.


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Revised: June 08, 1997    URL: http://www.jdhite.com/mouthpieces/shop2.htm

Standard pivot screws	The traditional pivot screw used on woodwind instruments has a tapered tip which allows it to be tightened into the end of the key hinge. Ideally, it should hold the key securely but not so tightly that it binds, restricting the free motion of the key. The screw must be adjusted to tighten precisely into the key so that it will eliminate any looseness or play in the action of the key hinge. After the instrument is played for several years, the action of the keys causes slight wear on the screw and the key. This wear allows the key to wiggle from side to side and creates extra noise in the key action. A repairman can correct this problem by deepening the screw seat in the post. The screw can then be tightened a quarter or half a turn more to advance it further into the end of the key, and the key will no longer wiggle. After this adjustment, the key will be secure in its action for another year or two of playing activity.
Problems with traditional design	Problems maintaining this precise pivot screw / key hinge adjustment are common. If the seating in the post allows the pivot screw to tighten into the end of the key to the point of binding the hinge as it tightens into the post, the pivot screw must be backed out until the binding is relieved. This loosens the head of the screw in the post because it cannot be tightened against the seating in the post. The action of the key causes the pivot screw to move with the action of the key. Consequently, over a period of time, the screw will "back out" of the post. A careful player will frequently check his instrument for loose screws, tightening them appropriately. Without this attention, the screw can totally unscrew itself from the post and drop away from the instrument. Unless the screw can be found and replaced, the player might be faced by an emergency of grand proportions. Worst case scenario, of course, is facing this situation just before going on stage for a concert or recital! (In an emergency, I would suggest whittling down the end of a wooden match stick to approximate the shape of a pivot screw. Force it through the post and into the key. This bit of patchwork will suffice until the instrument can be taken to a repairman for screw replacement and adjustment.)
New Buffet design	Following extensive research and testing, Buffet-Crampon has devised a new type of pivot screw. This screw has a nylon sleeve just below the head and above the threads. (The post must be drilled and threaded differently to receive this screw design.) The screw can be adjusted for perfect hinging of the key, and later, as the hinge wears, it can be tightened as needed to maintain the perfect adjustment. The nylon shoulder pivot screw has two advantages over the traditional design: First, as described above, it keeps the screw perfectly secure in the post while allowing for further adjustment into the key hinge. Second (... and this is a personal observation), it quiets the key noise -- that is, the "clank" of the key opening and closing. The nylon serves to dampen noise that may pass through the post into the instrument. It is my impression that the keys on instruments with the new screws are quieter even than optimally adjusted keys of the older design.
Use of the new design	Is it possible to replace the screws on older Buffet instruments with the new nylon sleeve screws? François Kloc, the recently appointed technical advisor to Boosey & Hawkes Musical Instruments, Inc. here in the United States, informs us that this is not practical. The posts must be specially threaded and seated to receive this new screw, and consequently, the screw is not compatible with the posts on older clarinets. Conversely, the old design screws cannot be transferred to the newer instruments. The new pivot screws can be found on all Buffet E-13 soprano clarinets beginning with serial number 111219 and all Buffet R-13 Bb and A clarinets beginning with serial number 426408.