 The Clarinet BBoard
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Author: Dan Shusta
Date: 2022-09-30 08:14
I have a new mouthpiece in front of me which the manufacturer states has a "length" (facing) of 17.5mm.
Just to make sure, I decided to measure it. Now, since I don't have an accurate 0.0015" feeler gauge, I decided to measure the length from where the light just begins to the tip of the mouthpiece.
So, I put the bark flat end of a reed over the facing extending it to 10mm from the tip and looked carefully for where the curve just started to show some light. I quickly put my plastic, mm ruler's edge at the point of initial light and looked at the tip for the measurement. I measured 17mm.
The purpose of this posting is to reveal my suspicions that there exists two completely different facing length measurement techniques in existence.
IMO, it seems to me that the facing lengths of CNC machined mouthpieces start at the beginning of the cut and end at the mouthpiece tip.
I also believe that boutique mouthpiece craftspeople still use the 0.0015" feeler gauge point as the beginning of the facing length and end it, again, at the tip of the mouthpiece.
This, unfortunately, kinda confuses me. I expected the 17.5mm facing to start light somewhere around 18 or even more but certainly somewhere beyond 17.5mm.
So, with me measuring 17mm, I suspect this mouthpiece actually has a Brand 32 facing (utilizing 0.0015" as the starting point) which might be defined as a medium-short facing.
Has anyone else noticed this?
Is there a new definition as to what actually constitutes how a true facing length should be measured?
I just measured the facing on my Prescott which is advertised as 1.01@36. From the initial point of light to the tip, I measured......18mm.
It definitely appears to me that CNC technology has totally changed the definition of facing length.
What do you think?
Post Edited (2022-09-30 08:54)
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Author: JTJC
Date: 2022-09-30 16:30
I believe you are correct. There're two different method of measuring facing, just as you describe them.
Peter Eaton refers to the facing length issue on his website. I've not had time to investigate but been wondering whether German facings are in fact measured using the the absolute starting point of the cut. While German mouthpieces have longer lays I'm not so sure actual differences between American/French facing lengths are so great in some cases.
From my measurements an18/19mm facing using the feeler guage method equates to around 21/22mm using the absolute method. Certainly into German territory.
There are also two methods of measuring tip opening, one using the inside edge of the tip rail and the other the external edge of the tip rail. Here again can you'll get a difference of around 1mm depending on which you use.
It makes far more sense to move the the absolute method. CNC mouthpieces have to be made that way as you have to programme the machine where to start its cut. That's the future.
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Author: kdk
Date: 2022-09-30 17:04
JTJC wrote:
> From my measurements an18/19mm facing using the feeler guage
> method equates to around 21/22mm using the absolute method.
> Certainly into German territory.
>
> There are also two methods of measuring tip opening, one using
> the inside edge of the tip rail and the other the external edge
> of the tip rail. Here again can you'll get a difference of
> around 1mm depending on which you use.
>
1 mm? that's double (or nearly) the advertised opening of most close-tipped facings. How do you measure the distance from the outside of the tip rail? A depth gauge across the tip to a glass? You can't use a taper gauge - if the tip rail is angled or curved back from the plane of the table your gauge will stop at the inner rail edge. I do have a couple of dial gauges that I can set (precariously) at the outside of the tip rail, and they do give larger dimensions than a taper gauge (but not as much as a millimeter). But I always feel that the seating of the gauge's probe on the edge of the rail is unreliable.
It's true that it would be helpful to know which way the mouthpiece maker or refacer is measuring his tip openings.
> It makes far more sense to move the the absolute method. CNC
> mouthpieces have to be made that way as you have to program
> the machine where to start its cut. That's the future.
I understand that a machine can be programmed to start a curve at a particular point and a manufacturer can then advertise that point as the curve length. But for hand measurement by end users or by hand finishers, how would you find that point? Any feeler however thin will stop short of the true, "absolute" method. So, the usefulness of measurement by feeler will probably continue for the purposes of comparison among mouthpieces until some kind of easily affordable and convenient gauge replaces it. No?
Karl
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Author: Mojo
Date: 2022-09-30 17:51
Yup a few makers do occasionally publish tables listing facing lengths to the tangent point and tip openings outside the tip rail.
I suspect they have unpublished internal specs that they use to measure the FL using a .0015” feeler for QC. Or, they do not do any checks.
MojoMP.com
Mojo Mouthpiece Work LLC
MojoMouthpieceWork@yahoo.com
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Author: kdk
Date: 2022-09-30 18:10
Mojo wrote:
> Yup a few makers do occasionally publish tables listing facing
> lengths to the tangent point and tip openings outside the tip
> rail.
>
How do they measure that? Or do they take the spec from the machine that produces the blanks?
> I suspect they have unpublished internal specs that they use to
> measure the FL using a .0015” feeler for QC. Or, they do not
> do any checks.
>
Maybe I'm just blanking out - what is QC? (I got Facing Length on my own)
Karl
Post Edited (2022-09-30 18:10)
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Author: Hunter_100
Date: 2022-09-30 18:30
Any machine shop would have the tools to measure and layout the entire curve. You could do it by using a dial indicator with the mouthpiece attached to the table of a milling machine for example and traversing across the mouthpiece profile.
I suspect most hand refinishers do not have such equipment though and the use of feeler gauges is a work around for more exact measurements.
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Author: kdk
Date: 2022-09-30 21:49
Hunter_100 wrote:
> QC is quality control.
Oh, yeah. Duh!!
Karl
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Author: Dan Shusta
Date: 2022-09-30 22:40
I just exchanged a few emails with Ryan Pereira of Pereira3D.com. He advertises his "standard" clarinet mouthpiece as being 1mm@36. I asked him if his 36 was a Brand 36 using a 0.0015" feeler gauge or did his 36 mean the curve cutting started at 18mm. He emailed me a very descriptive reply. I then asked for his written permission to share his comments here on the BB and this was his response:
Hi Dan,
Of course - feel free to share! I completely understand the discrepancies regarding measuring dimensions on mouthpieces. even those who measure tip openings with tip wands can get different readings as different tip wands can give slightly different readings.
Moving back to 3D printing, when I manufacture a mouthpiece blank, the facing length is typically a touch longer than 36 (typically 37 or 38), and once my mouthpiece craftsman does the facing work, the sanding brings it to 36 (all of this is when measured with the 0.0015” feeler gauge). As for CNC, I cannot speak to that since I haven’t worked with the CNC blanks myself. My 3D mouthpieces are the only product I offer where I collaborate with another craftsman, since, as you know, mouthpiece refacing requires a “special touch” to maximize a mouthpiece’s potential. Nikhil certainly has that touch with all the work he’s done for me!
Again, I hope this helps but let me know if I can clarify any info!
All the best,
Ryan Pereira
Pereira 3D Clarinet Services
Founder
www.Pereira3D.com
OK, it appears we actually do have two different facing length measuring systems and they are:
1) If the mpc is 3D printed, a 36 facing is a true Brand 36 facing with the use of a 0.0015" feeler gauge.
2) From my measurements of 2 CNC produced mouthpieces, a 36 and a 35 facing means the beginning cuts of the curves start at 18mm and 17.5mm.
Personally, I really don't like having two different facing length measuring systems, however, this appears to be the case.
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Author: Mojo
Date: 2022-10-01 16:33
Even a machinist with a dial indicator would have a difficult time measuring where the facing curve starts to curve away from the flat table. There is no well defined point there.
If you level the table perfectly, and it is flat, you can try to tell where the dial indicator first starts to drop. But that may not align perfectly with the CNC programmed used.
I measure the entire facing then fit a mathematical curve to the data. The starting point of this curve at the table would be facing length to a theoretical .0000 feeler.
MojoMP.com
Mojo Mouthpiece Work LLC
MojoMouthpieceWork@yahoo.com
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Author: JTJC
Date: 2022-10-01 20:48
I feel I must get very close to identifying the actual start of the table using the Theo Wanne tip opening gauge. That has a dial gauge and a flat machined table. However, you can in fact run the measuring tip along the whole length of the side rails and around the tip rail while keeping the machined surface flat against the mouthpiece table. There's always the issue of the measuring tip being a small sphere rather than an absolute point, but in terms of the needs for accuracy with mouthpieces surely that's sufficient? Mojo, you seem to say that's not quite good enough, but is it likely to be any less accurate than your calculated starting point?
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Author: kdk
Date: 2022-10-01 21:23
JTJC wrote:
> you can in fact
> run the measuring tip [of the Wanne tip gauge] along
> the whole length of the side rails
> and around the tip rail while keeping the machined surface flat
> against the mouthpiece table.
I feel as if Zeno's Paradox is in full operation here. Where physically is that .0000 mm starting point?
But on a much more practical level, have you ever experienced any marring or scratching of the rail surfaces by doing this. Running metal objects along the rails has always spooked me a little.
Karl
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Author: Dan Shusta
Date: 2022-10-02 03:42
To Mojo and JTJC,
Thank you both very much for your knowledgeable and experienced responses.
What I'm really trying to say is, from my point of view, both of you were challenging me and I'm glad that both of you did.
And, what was that challenge? I interpreted both of your responses as saying to me: "Can I really trust my eyesight to determine where the curve actually begins?"
And, now, the answer to that is a definite NO!
I resorted to the "light begins the curve" concept because I sincerely believed that it did. And now, I must admit that I was totally wrong.
I took another look at my Prescott. Only this time I looked for where the cutting may have started and..........I found it! After I did, I put a piece of white paper across the outer edges and then placed my plastic ruler against the paper. I then read the mm number at the tip. Now, I measured 19mm.
So, to sum everything up succinctly, the beginning edge of a sliver of light is not the beginning of the curve. Why? Because I have proven to myself that my eyes cannot see light shining through an opening of less than 0.0015".
Actually, I'm glad that I was wrong. Why? Because (for me at least) my faith in CNC machined mouthpieces has been restored. Proper CNC machining actually does produce a 0.0015" opening at the specified facing number listed for the mouthpiece.
Also, when it finally dawned on me that I have memory problems, I took my 0.0015" feeler gauge and placed it between my JJBabbitt glass measuring gauge and the mpc facing and..... I slid it all the way down to 36.
Mea culpa.
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Author: JTJC
Date: 2022-10-02 14:48
KDK, Yes, you do need to be careful running the metal gauge tip along the rails and not repeat the process too many times. But the same is true with feeler gauges. The edges of feeler gauges is quite sharp so can damage the rails as well.
I've seen one refacer on YouTube recommend taking that edge off, ever so lightly. However, the very edge is no longer the full thickness of the gauge, but only by a very small amount I suppose. The lack of a clear edge on the feeler will also affect how the feeler gauge sits in between the rails and the glass gauge and affect the reading you get. Of course, depending on whether you have the feeler gauge flat again the glass or against the rails, you should get a different reading (if anyone could actually detect that difference using a traditional glass scale).
Rather ironically , there's a point where any measurements are good enough for the relevant purpose. As with mouthpiece measurements, where that point is is a matter of preference, ability, tools, experience etc
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Author: Dan Shusta
Date: 2022-10-03 02:03
JTJC,
One thing that I would like to point out is that I believe there is a difference in the quality of glass measuring gauges.
In the photo, yes, I've had the JJBabbitt longer, however, if you'll look at the name on the glass gauge, even it has spots missing. This end, of course, is only slid up or down on the mpc until the tip of the mpc is at the Zero reference line. I should think that with such little friction movement, the name and lines around it should have remained pretty much intact Also note how thin all of the printing is on this gauge.
On the right side is my newer Theo Wanne. Yes, I have used it, however, no damage is seen on the lines or on the name. The white printing appears to be about 3 or 4 times thicker than the Babbitt. It is simply my judgement call that the Theo Wanne is a higher quality made glass measuring gauge.
p.s. The photo was just over 2 Mb. I'll try taking a smaller one and post it.
Post Edited (2022-10-03 02:08)
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Author: Mojo
Date: 2022-10-03 17:33
I have had a few Babbitt gauges. I have outsourced my own and I currently use a LAW gauge which is no longer made. I have my own stash of them.
Thinner lines are better for precise work. If you only measure to the nearest .5, and use +/- if the reading is a little higher/lower, a thick line gauge will do. I measure to the nearest .1, which is overkill but I do it.
I have a collection of gauges. Most of the thick line ones have silk screened scales on them with no etching into the glass.
Etching is done with acid or laser. Then a color fill product it used to make the stripes in the etching.
You can buy a color fill crayon to see if you can freshen up the lines of your Babbitt gauge.
The other thing to check is the scale. Hold them on top of each other to see if they match up. Or use calipers to check if the distance from zero to 50 or so is correct. I have a few in my collection that are off.
MojoMP.com
Mojo Mouthpiece Work LLC
MojoMouthpieceWork@yahoo.com
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Author: JTJC
Date: 2022-10-03 20:47
Thanks Dan.
I have a Wanne glass. Yes, it looks well made and a quality item. However, I think the lines are far too thick, which your photo illustrates. That makes determining an accurate reading more difficult. It becomes a matter of judgement rather than just reading off the scale whether a measurement is nearer any particular subdivision of a mm. So for example, I find whether a reading is 15.6 or 15.7 is difficult to determine. However, Mojo says he goes to that level and its overkill.
I seem to remember reading a quote on this board that one of the American mouthpiece greats, Matson I think, said something to the effect that within 0.3mm it didn't matter and the effect on playability wasn't noticeable. If that's the case the Wanne guage might be accurate enough. Provided that is, it's used consistently. It takes time to learn use one of those glasses. Even holding it in exactly the same place against the mouthpiece as you go through all the feeler guages and record the readings really hurts your thumb. If you slip even a little you have to start all over.
That's why I've tried to look for another, less painful, method of doing it. A digital dial guage with data output might provide the basis for a solution.
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Author: Paul Aviles
Date: 2022-10-03 23:19
I've been told a similar assessment by another well known maker of mouthpieces about how dimensions of that size are less than the width of a human hair. However, we DO feel the difference. Anyone who has had a second custom mouthpiece made by the same maker (so the same specs OF COURSE) will tell you that even with those careful criteria, YOU WILL NOTICE a difference between the two.
HOWEVER
It "doesn't make a difference" when you give yourself a few weeks to get used to the difference and resume playing without that subconscious feeling of something being wrong or missing.
...............Paul Aviles
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Author: Dan Shusta
Date: 2022-10-04 01:08
JTJC,
When you stated: "A digital dial gauge with data output might provide the basis for a solution." I agree.
However, wouldn't two important digital readings be necessary?
1) The depth from the flat table surface
2) The distance from the tip edge of the mpc.
I just don't see how this can be done with only one instrument.
As to hurting your thumb, I've been there. I actually got to the point of wrapping a very thick rubber band around the mpc and glass gauge several times. To get the tip of the mpc to Zero on the gauge, I would slide the mpc to the proper point, hold the mpc firmly against the glass gauge and then I'd move the rubber bands at the bottom of the mpc for proper stabilization. Not really the "proper" way of doing it, but, it worked OK for me.
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Author: JTJC
Date: 2022-10-04 17:38
Hi Dan,
My ideas on the use of a digital dial guage for measuring the lay haven't been fully worked out yet. I can use the tip gauge I refer to and run it the length of the rail and past the Zero point. That's the basis of it. The idea is to have a jig which would hold the tip guage and allow it, or the mouthpiece, to be incrementally moved the length of the rails, say in 1mm or 0.5mm increments. That way you get both measurements - position along the rail and depth (from the flat surface, what a feeler gauge would usually be measuring). The thing measuring the increments is in fact the second tool you refer to, but it's part of the jig, it would be a scale on it. Because the dial gauge has a digital data output readings could be automatically and reliably taken via cable to PC or other device.
There are a number of problems to work through. Setting the Zero point is one. The lay starts at Zero, the point at which the curve starts on a rail. But there are two rails and they may not be symmetrical - they are not the same distance from the tip. So there would be a need to accurately align the readings from the two rails. I'm still thinking about all this.
However, I may not get anywhere as it gets very messy. The measuring tip would need to follow a path along a rail, end to end. Mouthpiece rails are not necessarily flat across their width. Apart from manufacturing inaccuracies there are things like Rail Tilt. So, which part of the rail across its width to measure on? It needs to be set as it'll be used for all mouthpieces. Feeler guages avoid this problem by riding on the 'highest' part of the rail width.
Re the sore thumb and need for a consistent position of measuring glass to mouthpiece. I like the rubber band idea. I thought maybe some sort of box arrangement might do it. Mouthpiece would be held in a small box and the glass would go on top, over the lay. Position of the mouthpiece would be adjusted and fixed via screws in the sides of the box. Alternatively, the glass measure is adjusted, and fixed, relative to the mouthpiece. One screw/adjuster to alight the mouthpiece tip with the zero on the glass gauge. A second adjuster for side to side adjustments, to ensure gauge and mouthpiece are symmetrical.
All just ideas. I think I'm stuck with glass gauge and thumb for quite some time.
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Author: Dan Shusta
Date: 2022-10-04 20:23
Hi JTJC,
Another "holder" idea I came up with last night was so simple it surprised me.
How about simply using a "PADDED" "C" clamp? I haven't tried it yet, however, I think it would work quite well.
When a position adjustment needs to be made, just slightly loosen the "C" clamp, reposition either the glass gauge or the mpc, and then just "snug up" the padded clamp. I suggest a thin layer of rubber on the clamp holders to prevent slipping.
Good luck with your project!
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Author: Dan Shusta
Date: 2022-10-10 03:27
When I pulled out my Theo Wanne measuring gauge a short while ago, I quickly noticed how much LIGHTER[/B] the line color intensity was and the lines were just as THIN as the lines were in the JJBabbitt glass measuring gauge. I took another picture, however, the lines still do not show a correct image of the Theo Wanne glass measuring gauge. Then I finally figured it out...IT'S THE CAMERA IN MY CELL PHONE!
I felt the need to correct this as soon as possible.
So, for the record, the lines on the Theo Wanne are just as thin and much fainter in light intensity than the JJBabbitt.
Sorry about that!
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Author: Dan Shusta
Date: 2022-10-10 03:30
Attachment: New photo of gauges.jpg (702k)
When I pulled out my Theo Wanne measuring gauge a short while ago, I quickly noticed how much LIGHTER the line color intensity was and the lines were just as THIN as the lines were in the JJBabbitt glass measuring gauge. I took another picture, however, the lines still do not show a correct image of the Theo Wanne glass measuring gauge. Then I finally figured it out...IT'S THE CAMERA IN MY CELL PHONE!
I felt the need to correct this as soon as possible.
So, for the record, the lines on the Theo Wanne are just as thin and much fainter in light intensity than the JJBabbitt.
Sorry about that!
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Author: Paul Aviles
Date: 2022-10-10 04:43
So, I've never had the measuring dohickies and never tried is myself BUT it appears to me that there are clearly FIVE LINES that lead up to the "10" designation. I thought dividing the millimeters into halves was supposed to make measuring more accurate. HOWEVER, if you only have divisions of ONE millimeter at at time, how do you achieve this vaunted accuracy?
anyone?
...............Paul Aviles
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Author: Dan Shusta
Date: 2022-10-10 06:13
Hi Paul,
Since the distance between each line is 1 (one) mm, at Brand 10, the actual distance from zero is 5mm.
However, I think I see your point. The Fobes CF has a facing of Brand 34.5. To my understanding, that means 0.5 is one quarter of the distance between 34 and 36. (Since 35 would be right in the middle between 34 and 36.)
How to achieve this accurately? Well.., the two words that come to my mind is approximation and.....estimation when using a Brand measuring glass gauge.
And, IMHO, that's not very accurate because the pressure pushing on the gauge would have to be the exact same amount every time. That, for me, is very hard to do.
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Author: Paul Aviles
Date: 2022-10-10 07:32
Thanks Dan!
Just another reason why I will let this remain the realm of the mouthpiece guys.
.............Paul Aviles
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Author: Mojo
Date: 2022-10-10 17:23
The 2*mm glass gauge was chosen to get .5mm resolution without using decimals. A 19 reading would be 9.5 mm. But refacers started using .5 scale reading and +/- modifiers right away to get finer readings anyway.
I measure to the nearest .1 on the glass gauge. Not easy and not very repeatable but I do it anyway. I even have a video where I explain how I do this. But you need great vision. You could never get factory workers to do finer than a 1/2 scale division reading.
MojoMP.com
Mojo Mouthpiece Work LLC
MojoMouthpieceWork@yahoo.com
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