 The Clarinet BBoard
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Author: beejay
Date: 2000-06-10 21:40
Please could someone explain what is meant by the phrase "undercut tone holes." And why is it advantageous?
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Author: Don Berger
Date: 2000-06-10 22:02
I didn't find it under "undercutting", but Lee Gibson [in "Clarinet Acoustics"] has Chap. 11 re: Tone Holes where the ?French? term is used and is prob. what you are looking for. Others of our good books will discuss this technique. As in many things, there are +'s and -'s. Good research, Don
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Author: Eoin McAuley
Date: 2000-06-10 22:36
When I was looking into buying a clarinet, I noticed that one of the features of the clarinet I intended buying was undercut toneholes. I assumed this was some advanced manufacturing technique which gave it an advantage over other clarinets. After some research, I found that every single clarinet on the market has undercut toneholes. It is therefore nothing special and I lost interest in it. I never found out what it meant or why it was worth mentioning!
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Author: Mike Hancock
Date: 2000-06-11 02:13
In regard to this topic.....my understanding is that undercutting/fraising is common only on professional quality instruments and is used partly to correct intonation throughout the range of an instrument. As Don Berger points out, there is an excellent discussion of this in Gibson's book.
I have also asked an instrument tech about this and was shown the set of custom reamers that are used for this purpose. Further, when I asked to see an example of an instrument that has undercut tone holes and one that does not, I could not tell the difference based on an "eyeball" examination and comparison.
$0.02 worth......
Mike Hancock
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Author: Don Berger
Date: 2000-06-11 18:49
Rendall,"The Clarinet", 1st edition, pg. 49+ gives a fine description of "this very old practice" and its effects. It prob. is in all good libraries, good reading!! If my LeB L7's C#/G#, F/C etc tone holes are "fraised" I cannot detect it, but their contributions to good tonality is greatly appreciated!! Don
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Author: Graham Elliott
Date: 2000-06-12 07:47
If you imagine the tone hole as a "chimney", an undercut one has a wider opening into the bore than into the outside, though the gradient of the undercutting and extent will vary considerably. Helps with intonation, and is said to give the instrument a more flexible and fluid feel. Many older clarinets are very heavily undercut compared to modern ones.
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Author: paul
Date: 2000-06-12 15:04
As mentioned above, there are situations where undercutting the tone holes buys you an advantage, and there are times where it doesn't. Classical clarinets I believe benefit greatly from fraising (undercutting), narrow bores, and from the polycylindrical bore design. I believe that jazz clarinets' tone holes should be straight cut and that they should be large/straight bored. Note that these are opinions only, folks.
One quick "player's view of the world" test will let you know if your horn has undercut tone holes. It certainly isn't exact, but what the heck, it's free and easy to try. So here goes...
The quality of the produced tone varies with the accuracy of fingerings, right? If you let your fingers droop a bit when they shouldn't (chalemeau register D with left third finger drooping over the C tone hole, or C with right middle finger drooping over the middle tone hole for B, etc.), you will notice there is a certain spot where your fingertip affects the note. In theory, straight cut tone holed clarinets are much less sensitive to sloppy fingerings like this, but the resulting tone from an accurately fingered note is a bit bland. Undercut horns are more sensitive to sloppy fingerings, but the produced tone is much richer, much more appealing to the ear. I did a 1:1 test with intermediate horns like this a few years back, and I could almost instantly tell the undercut horn from the straight cut one. In addition, the undercut horn required a bit more air support. It was a more challenging horn to play from the novice perspective.
From my personal perspective, I think of straight cut horns producing more of a hard/pointed or "square" wave output on an oscilloscope and the undercut horns, because the tone holes are rounded off, producing more a set of slightly rounded off waves. This may or may not be totally scientifically accurate, but the analogy seems logical.
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Author: Don Berger
Date: 2000-06-12 15:14
Thanx, Paul, very interesting, will try your suggestions and report!! Don
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Author: Eoin
Date: 2000-06-13 07:20
Paul, you seem to know a lot about the effects of undercutting. Can you answer the original question, what is undercutting? We still don't know.
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Author: Karlheinz
Date: 2000-06-13 14:41
Information on this topic is also provided by Yamaha on its virtual factory tour at:
http://www.yamaha.co.jp/edu/english/factory/cl/index.html
KJ
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Author: Don Berger
Date: 2000-06-13 16:28
Eoin, since Paul hasn't answered yet, to me it is a tapering of the tone hole starting in the bore, using a "fraize" which I believe is a tapered drill activated by a small, right-angle drill shaft and performed very carefully and progressively with testing by a true expert. I believe that a photo in an 80's ICA mag. shows Hans Moennig doing just that. I'll look for it. Don
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Author: Mike Hancock
Date: 2000-06-13 16:31
Thank you Karlheinz.......
Yamaha has provided an enlightening site with an interesting review of clarinet manufacturing. Their description of "undercutting" is very understandable and the tools look like those that I was shown.
Mike Hancock
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Author: paul
Date: 2000-06-13 19:16
Fraising or undercutting of the tone holes is done by rounding off the tonehole edges from the inside out. Remember, the air goes from the bore and then out, right? The trick is to minimize the turbulence of the exiting airstream caused by the orginally sharp edges. Round off the edges and you have a less turbulent and better sound. At least that's the theory. It's obvious that horns have the finger tone holes undercut. That's where most folks can catch a glimpse of the work if they look very carefully. But, did you know that almost all of the tone holes are eligible for this kind of work? For the folks who would like to play the game, name the tone holes that will never be undercut and say why they won't be undercut. Come on now, think about it. If you need a hint, take a detailed look at your own horn, both inside and out.
So, why is it called fraising? Fraise is French for strawberry, which is the rough shape of the cutting tool.
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Author: Mike Hancock
Date: 2000-06-13 19:58
I accept the challenge and will start with the Register Key tone hole and the Left Thumb tone hole just below it because they both have inserts that extend into the bore.
Mike Hancock
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Author: Mark Charette, Webmaster
Date: 2000-06-13 20:36
The register tube itself may be "undercut" if you consider that special Moennig replcements are available. They are rounded at tne bore entrance and have an internal hourglass shape.
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Author: paul
Date: 2000-06-13 21:38
Mike and Mark:
Bingo!
The register tube sticks into the air stream of the inner bore and the thumb hole also has an insert. Give Mark C. double points on the modification that could make the thumb hole eligible, too.
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Author: Willie
Date: 2000-06-14 04:47
You want a real challenge? Try doing a custom job on an old Pan American or Artley. If you can make it play in tune with good tone, you will be probably called Merlin there after.
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Author: Don Berger
Date: 2000-06-14 15:45
Paul #1, "fraise", yes in one dict. = strawberry, in the RD Encyclopedic Dict, several meanings incl. "a watchmakers tool". Paul #2, interesting! Willie, yes, your nominations could be under the-above "worst horns"!! Don
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Author: Don Berger
Date: 2000-06-15 14:32
I found another dictionary, which under "fraize" said [3] [mach.] [machine technology, prob], countersinking, in our case at the "bottom" of the tone hole. Nuff said? Don
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Author: Avie
Date: 2003-11-30 13:15
If the ct'sink dia. is larger on the bottom of the tone hole there would have to be a special expansion tool that could be down sized in order to remove the cutting tool unless it can be disassembled from the shank after fraizing and then dropped out thru the bore. I think that the term undercutting is interpreted differently by everyone or maybe it is something different. I still dont understand what positive effect that design would have on the tone with the hole being larger on the bottom. Maybe if we could see what the cutter looks like it would clearify what an undercut tone hole actually looks like, how its machined and what positive ot negative effects it would have on the instrument.
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Author: Mark Charette
Date: 2003-11-30 14:24
avumba wrote:
> If the ct'sink dia. is larger on the bottom of the tone hole
> there would have to be a special expansion tool that could be
> down sized in order to remove the cutting tool unless it can be
> disassembled from the shank after fraizing and then dropped out
> thru the bore.
There's an 'L' shaped rod (bent at 90 degrees on one end) that carries the undercutting tool into position in the bore (moved to the correct hole). Than another piece is threaded into the tool through the hole and tightened. When assembled it looks very much like a key to tighten a drill chuck, but the "gear" part would be facing the other way.
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Author: KENOLD
Date: 2003-11-30 18:50
Here is an image of a tool used to undercut tone holes.
The cutter bit is place in the bore of the clarinet before it is attached to the cutter shaft. The tone hole is then enlarged or UNDERCUT on the bore side of the hole. The finger/pad side of the tone hole is unchanged.
http://www.chadashclarinet.com/images/finishing7.jpg
Ken
Learn to perform even the things you don't like, as if you love to do them.
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Author: Gordon (NZ)
Date: 2003-11-30 19:40
I imaging that during manufacture, there could be a similar tool, but smaller in diameter than the tone hole.
A CNC (i.e. computer controlled) machine would spin the cutter, insert it through the tone hole, and then work around the lower edge of the tone hole in a VERY controlled manner, all in a few seconds.
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Author: ron b
Date: 2003-11-30 21:03
Don't overlook the most obvious and prominent tone hole of all... the BELL. By no stretch of my imagination could I concientiously call that thing "fraized" in the sense that we're using the term here. Nevertheless, all my horns' low E and middle B notes sound quite good, to me anyway.
While fraizing *might* make a clarinet a bit easier to blow, so much for the fancy ideas of making for a better sound. You're not likely to convince me that undercutting does anything to improve intonation either.
- r![[cool]](http://test.woodwind.org/clarinet/BBoard/smileys/cool.gif) n b -
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Author: Gordon (NZ)
Date: 2003-11-30 23:12
I would regard the bell, with its long, gradual increase in diameter as acoustically quite a separate set-up from a short-length, smaller-than-bore-diameter tone hole.... beyond comparison.
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