 The Clarinet BBoard
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Author: clarinet60
Date: 2008-09-17 20:36
Does anyone have any history or background on a Kell Geometric mouthpiece? It is a vintage piece and seems to have a slight duck bill and is marked MO.
Thanks.
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Author: Don Berger
Date: 2008-09-17 21:29
Hi cl60 - I have a Kell MaxiTone Bb mp with an M [T?] in the back's area of the upper lig's "strap" location. As to ?duck bill?, mine has an ending curve in its beak. What is meant by "geometric"?, I can/will measure the bore if desired. It's my "dark" mp as of now. Don
Thanx, Mark, Don
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Author: L. Omar Henderson
Date: 2008-09-17 23:12
All molded mouthpieces are anything but geometric. My recent foray into mouthpiece prototypes indicates that the intense heat and pressure in the "egg" during vulcanization and subsequent uneven cooling introduces a degree of assymetry to all molded mouthpieces, and each is different. Subjecting a high quality mouthpiece blank to precise measurement shows a surprising deviation from an exact parametric (geometric if you will) model. See the attached pictures with yellow, and blue indicating deviation from symmetry. Only with precise machining of rod stock can a more nearly symmetric mouthpiece be made.
L. Omar Henderson
www.doctorsprod.com
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Author: tictactux ★2017
Date: 2008-09-17 23:22
> Only with precise machining of rod stock can a more nearly symmetric
> mouthpiece be made.
Is this crucial? I mean, slapping a (by nature) asymmetrical (or asymmetrically behaving) reed on a perfectly symmetrical mouthpiece will yield nearly just as unpredictable results as using an (ever so slightly) asymmetrical mouthpiece, no? The effect is the same - either the reed goes into the bin, or the player is adjusting, scratching, whatever is needed for a better result.
(I don't mean to advocate sloppy manufacturing and all that - I just wonder whether we're tuning the right part...I honestly don't know)
--
Ben
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Author: L. Omar Henderson
Date: 2008-09-17 23:38
Attachment: 1MPDeviation100.jpg (110k)
You are right about the reed component. But, it seems that very small adjustments to the architecture of the mouthpiece however affects how any reed will play. I do not know that assymetry is a bad thing except in the table and rail alignment of the mouthpiece (according to several custom mouthpiece makers queried) however changes in the baffle or inside in the tip area seem to make huge differences in how a mouthpiece plays - again, with a series of reeds. We all know the failings and delights of bad and good reeds but they too only create the fluctuating air column which is modified by the mouthpiece architecture.
Hopefully attached are the missing photos.
L. Omar Henderson
www.doctorsprod.com
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Author: skygardener
Date: 2008-09-18 11:19
"Only with precise machining of rod stock can a more nearly symmetric mouthpiece be made."
Why?
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Author: Bassie
Date: 2008-09-18 12:27
Why? Moulding (casting) is an inherently imprecise process. Typically for precision work you'd mould ('near-net-shape') then machine - or even start with a plain bar and machine from that, as has been suggested.
I wrecked the first mouthpiece I 'refaced' by playing about with the bit just inside the tip...
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Author: L. Omar Henderson
Date: 2008-09-18 12:37
As indicated earlier, the mouthpiece blank may come out of the mold in symmetrical fashion but it is soft and flexible at this point and only becomes hard after the vulcanization step which subjects it to high heat and pressure in a special apparatus commonly called an "egg". It is then allowed to cool and since it does not have a uniform thickness there are certain parts that cool more quickly than others which introduces differential forces which tend to bend and twist the final shape. These forces may be unique to each mouthpiece, each "egg", and each batch of mouthpieces. Manufactured mouthpieces are then faced with a milling machine which tends to put a pretty consistent facing on each but the heat at the point of surface contact of the milling machine too causes the rubber to bend slightly and there are still some irregularities in facings applied by this process.
Machining a stock hard rubber rod is more precise because the rubber is already hardened and with CNC machining techniques the tolerances can easily be kept very close to symmetry if the model used to produce the programming of the machine uses a parametric model. The rubber formulation too can be different than used in the molding process due to constraints imposed by the vulcanization techniques subsequently used to vulcanize the molded format. There are caveats with CNC machining too because even though the milling head is constantly cooled with fluid there is still some surface heating and deformation during the process so adjustments must be made to the final CNC program after accurate measurements are made on the finished mouthpiece to determine if it follows symmetry. Facings are best applied by hand finishing which allows a more precise finish.
L. Omar Henderson
www.doctorsprod.com
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Author: skygardener
Date: 2008-09-18 12:45
Hand finishing is another way to ensure accuracy and consistancy.
I have seen some mouthpieces produced (as far as I know about the company) from rod stock that are not even close to eachother. Far beyond the margen of err when one could excuse it saying 'No 2 things are exactly the same'. By the same token I have seen mould mouthpieces more accurate than those inaccurate machined one's mentioned above.
I suppose Omar's statement is really about the 'precise machining' more than just the 'machining'.
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Author: Don Berger
Date: 2008-09-18 14:06
HEY, Guys, we seem to have lost sight [site?] of cl60's initial question, haven't we ? While learning much more of the mysteries of mp making, perhaps generating another MouthpieceWork Group [not the Yahoo's], except for Omar's contributions, we have not yet heard from our own skillful sop. cl MP makers ! Hand finishing/measuring is best, but expensive IMHO. Just my AM thoughts, ?OK, GBK? , Don
Thanx, Mark, Don
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Author: clarinet60
Date: 2008-09-18 14:45
Thanks Don. I appreciate all of the other info, but was simply looking for perhaps who made the blank, the age, whether it has any relationship to Reginald Kell, etc..Please help if you have any info. Thanks.
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Author: Grabnerwg
Date: 2008-09-18 16:59
Omar said <<There are caveats with CNC machining too because even though the milling head is constantly cooled with fluid there is still some surface heating and deformation during the process so adjustments must be made to the final CNC program after accurate measurements are made on the finished mouthpiece to determine if it follows symmetry. Facings are best applied by hand finishing which allows a more precise finish.>>
I think this couple of sentences says a lot. One of the very tricky things that we never really think about is that the materila we like best for mouthpieces is rubber.
Rubber is not stainless steel, it is not titainium. Even after vulcanization it is a flexible material that gives while it is being worked on and is very vulnerable to heat. We would have much more consistancy in measurement if we used other materials. Many have been tried, but we still keep coming back to rubber as, after all is said and done, most people prefer the sound it produces.
I have worked with blanks milled from rod rubber and cut using CNC technology. In the ones I have tried, there was still a large degree of difference, with each blank having more individual differences than most molded blanks.
Now perhaps I got inferior blanks. I can't say. I was able after MUCH hand finishing to produce some very superior mouthpieces. But I did much more in the way of invasive techniques (like a large amount of hand filing the baffle right below the tip rail) than I have to do on molded blanks.
There are many problems with molded blanks, of course. I have about three drawers full of molded blanks that I will never sell as finished mouthpicecs, as one way or another they have a problem that cannot be cured with hand (or perhaps any other) methods.
There is no clear winner here, but I will say that the CNC blanks that I have used still required what I thought was an enormous amount of hand finishing.
Walter Grabner
www.clarinetxpress.com
World Class Clarinet mouthpieces
New Buffet Clarinets
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Author: L. Omar Henderson
Date: 2008-09-18 18:38
Sorry, did not mean to muddy the waters on the original question !!
I am sure that custom makers have seen their share of good and bad molded, and in some cases machined blanks in the past. Inferior blanks lack quality control checks - and consistency depends on the quality control parameters used to access the finished blanks. If stringent quality control measures including accurate measurement techniques are employed on run samples then there should not be differences of more than 0.005 mm in any part of the blank, or from blank to blank - this can be done and is done.
The hard thing to accomplish with CNC is making 90 degree or acute angles at corners (which a mouthpiece has several) since the milling tools are all round and there will be a radius at "hard" corners. These require a second milling step to make them square with different machinery.
Since there are so many variables that interact in a finished mouthpiece, and each custom maker has their own way of manipulating these variables, then a universal blank is probably not possible that does not require a lot of hand work by the maker to customize it to their particular final configuration. The answer might be a custom blank for each mouthpiece maker which was very close to their normal end product and would require much less excavation and finishing.
Extremely accurate mouthpiece measuring (the hard and expensive part is the interior features) is routine but very costly. A parametric model can then be constructed from the measurements and translated into CNC control language. All of the milling steps, sequence, and special jigs for holding the semi-finished blank are another whole story and is not an easy or quick process to accomplish.
L. Omar Henderson
www.doctorsprod.com
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