1. Introduction to Modern Mouthpiece Refacing Techniques
Keith W. Bradbury
Mojo Mouthpiece Work LLC
January 23, 2009
Hi, I'm Keith Bradbury a.k.a. MojoBari on the web, but you can call me Mojo.  If you have hung out at all at the various sax forums you probably have run into my posts or what others post about my work.  Let me tell you about my background and how I got into mouthpiece refacing and hand finishing work.
First, like many of you, I began playing sax as a kid in the public school system.  Taught myself flute and clarinet in high school.  Had to relearn a lot of stuff properly later, but its been a great ride.  Played in college band at Rutgers where I got a BS degree in Mechanical Engineering in 1979.  Went to work in industry as a process engineer and got a MSME degree from Drexel in 1984.  I spent over 28 years working in industry.  Musically, I've played a lot of local gigs in southern NJ.  Mostly Big Band, Pit Orchestras, Community Bands, Church, some weddings and Atlantic City work.
After discovering the web, I soon developed an interest in mouthpiece refacing and hand finishing work.  I had a few pieces done for me and I thought, "I can learn this".  Initially I was going to put it off until retirement from my day job as an Engineer.  But I pushed up the schedule when I started having muscle problems and an early diagnosis indicated that I would loose a lot of hand control.  Fortunately the outlook for my hands looks fine now. 
November 12, 2018
Copyright Mojo Mouthpiece Work LLC

2. Skills Needed to Hand Finish a Mouthpiece
Be analytical
Having an engineering/ technical degree helps.
Listen to sound and what people say.
Take measurements and keep notes.
Learn/develop theories why stuff works.
Try stuff, evaluate the results.
Be a craftsman
Acquire proper gauges and tools.
Be good with your hands, tools and methods.
Take pride in your work.
These are skills you should look for in a refacer, or posses if you want to learn this craft.
November 12, 2018
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3. Skills Needed to Hand Finish a Mouthpiece [cont]
Be a player
Do not need to know classical/jazz theory or be a reader. Just have command of the horn.
Have a developed embouchure.
Play a variety of styles.
Be a doubler, own all the horns.
Have experience
Have a great teacher/mentor.
Be able to learn on your own.
You can be weak in one area and compensate for it in another. Just like anything in life.
For a successful business, add Marketing and People skills. Communication, fair pricing and turnaround.
Is perception part of a good mouthpiece? If so, then cosmetic work can be very important.
November 12, 2018
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4. Copyright 2009 - Mojo Mouthpiece Work LLC
Available Literature
Band Instrument Repairing Manual
by Erick D. Brand (1939, 1942, 1945, 1946)
Available from Ferrees Tool
Contains 21 pages on mouthpiece work
The Saxophone is my voice by Ernest Ferron (1997)
Contains 13 pgs on mouthpiece acoustics
Has lots of easy-to-understand sax science
Both of these are highly recommended. But a lot of what you need to learn is not documented.
November 12, 2018
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5. Available Literature [cont]
Woodwind Mouthpiece Selection
by Robert Scarff (2002)
A good book for those who are not web surfers
Clarinet and Saxophone Mouthpieces
by Professor Anton Weinberg (2008)
Comes off as detailed mouthpiece catalog descriptions
The Scarff book is good, but real basic. But a lot of players need to know the basics.
I do not really care much for the Weinberg book.
November 12, 2018
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6. Available Literature [cont]
Ph.D. Thesis: An Acoustical Study of Alto Saxophone Mouthpiece Chamber Design by Frederick Sterns “Larry” Wyman (1972)
Available for download on the web
180 pages of empirical studies documentation
Fundamentals of Musical Acoustics
by Arthur H. Benade (1990)
596 page college text
Wyman’s paper is fabulous. Fairly easy-to-read and full of good experiments and results.
Benade’s text is just that. A college level text. It covers all instruments including single reeds. Not an easy read.
November 12, 2018
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7. Copyright 2009 - Mojo Mouthpiece Work LLC
Noteworthy Web Sites
MojoMouthpieceWork.com – has Link to:
Yahoo Mouthpiece Work Group - see the Links, Files, Photos, Posts on tools, spreadsheets and methods
TheoWanne.com
Mouthpieceworks.com
forum.saxontheweb.net
My personal site and a link to the Yahoo group I started in 2002.
Theo’s site has great stuff in it. The Mouthpieceworks.com site is Joe Smallwood’s site. No one I know has heard from Joe in a while but his site is still active and has good stuff in it.
November 12, 2018
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8. Copyright 2009 - Mojo Mouthpiece Work LLC
Basic Tools
Glass Gage – Unique to facing work
Feeler Gages – Large sizes too
Tip Gage – Calipers are a good start
Work Surface – 3/8” x 9” x 11” glass plate
Sandpaper – grit
Half Round Tapered Needle File
PC with spreadsheet program
Theo, Mojo, and J.J.Babbitt sell good glass gages.
The smaller feeler sizes are easy to find a an automotive tool store. The larger sizes are difficult to find. Theo and Mojo sell them. Also see Mitchellstore.com.
Some like to use granite work surfaces.
These are the grits I like to use. Some refacers prefer grits in the range.
This one file is a” must have”. Others are occasionally useful. MicroMark.com has inexpensive needle file sets. I like yellow-tang files from Jewelers’ suppliers.
The spreadsheet is what propels this craft into the 21st century!
November 12, 2018
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9. Copyright 2009 - Mojo Mouthpiece Work LLC
What to start on?
Measure, Measure, Measure
Plot curves - Look and correlate good playing mouthpieces with curve shapes.
Also consider design features
Baffle shape, sides shape, throat size
Experiment with temporary putty in a mouthpiece to try different baffle shapes
Reverse Engineering!
Read posts on Yahoo Mouthpiece Work Site
You need to practice measuring until you get fairly repeatable results.
Curves are plotted in a spreadsheet and exaggerated to highlight the differences.
The 3D features of a mouthpiece are difficult to capture with measurements. You need to develop an eye for them to supplement measurements. Photos help too.
Get a large chamber mouthpiece like a Link and try some putty in it to make some higher baffle shapes. Use dental wax, poster-hanging putty, Play-Doh, Silly Putty, etc.
Try to figure out what shapes and locations in a mouthpiece are significant, and which ones are not or are that way because it is easy to make.
The Yahoo site has detailed lists of tools, materials, and suggested refacing steps to work on.
November 12, 2018
Copyright Mojo Mouthpiece Work LLC

10. Flattening a Mouthpiece Table
Benefits: air tight seal, less reed picky
Problem: facing gets short
Check the table flatness
Straight edge
Light sandpaper scuff
Optional concavity to
account for reed swell
You can check for flatness by looking for light showing under a straight edge.
You can also take a light pass on very fine sandpaper and look for where it scuffs the table. This illustrates the high spots.
Some have a concavity to allow for reed swell. I prefer flat tables, but a slight concavity can work fine. Convex tables are bad.
November 12, 2018
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11. Flattening a Mouthpiece Table [cont]
Why flattening and closing a tip is tricky
Free body diagram forces
Push/pull technique not a good idea
Your hand force is the red arrow pulling to the right. The sandpaper force is the red arrow of friction pulling to the left. They are not in line so this creates a couple force on the mouthpiece that is shown by the green arrows. This couple force tends to drive the heel of the mouthpiece into the table which removes more material from the heel than the rest of the table.
If you attempt to counter-act this by pushing on the mouthpiece, it takes more material off the other end of the table. The middle of the table gets less material removed and the table becomes convex.
Being aware of these forces at play helps to properly counter-act their effect.
November 12, 2018
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12. Flattening a Mouthpiece Table [cont]
Flattening concave tables – common in Babbit Links and Meyers
Straight edge
3-point contact… scuff pattern growth
Bias force to table heel unless closing tip
This type of concavity is fairly easy to see and fix.
The 3-point scuff pattern, shown in red on the table, grows until they meet in the center of the table.
Since the two rail areas are small, they will cut faster than the heel. This will close the tip opening and shorten the facing curve a lot. So it is a good idea to press down on the heel a little if you are trying to maintain the tip opening. You can press down on the heel a lot if you want to open the tip a little.
November 12, 2018
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13. Flattening a Mouthpiece Table [cont]
Flattening convex tables – usually from bad hand finishing
Straight edge
Light sandpaper scuff
Can try to make concave first
Bias your hand forces and watch scuffs
Flattening a convex table can be maddening if you do not properly bias how you hold the mouthpiece.
If you do not bias your forces, then a light sandpaper scuff will remove even more material from the already low heel area.
You can try and attack the middle of the table buy sanding a low spot there until the table has a concavity. The go back to my concave slide and try to flatten the table using the concave strategy.
But I find that the best way is to heavily bias your hand forces so that you are lifting the heel off of the paper as you sand the table. This removes material from the red area on the bottom illustration. It takes practice to not overdo the bias. You want the scuff shown in the red area to grow towards the heel of the mouthpiece as you make more passes on the sandpaper. This area stays flat and grows bigger and bigger until the entire table is flat.
November 12, 2018
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14. Flattening a Mouthpiece Table [cont]
Angling a table to open a tip
~3:1 heel to tip ratio
Need to remove a lot of heel material
Need to trim the table width
Ligature will get loose
Some refacers prefer to angle the table to open the tip of a mouthpiece. Some call this a “bias butt cut”. They think this method better preserves the baffle relationship at the tip as compared to tip cutting. But there are trade-offs.
The slide shows that to get a .020” more open tip, you need to take .048” off the heel. In practice, the tilt point is difficult to maintain so you end up needing to take more like .060” off the heel (maybe I need more practice).
The table width gets wider as shown in the upper illustration. So you need to trim the sides of the mouthpiece to make it easier to center up the reed on the table. The Erick Brand manual illustrates table trimming, but it is pretty straight-forward.
Now with the tip more open, the mouthpiece will sound a little darker. If you do not want that, it would have been better to do some tip cutting so that the baffle gets a little higher. Then you can lower it as needed to get back to the sound you want.
November 12, 2018
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15. Copyright 2009 - Mojo Mouthpiece Work LLC
Facing Curve Analysis
Measurements
Using a glass gage and a set of feeler gages.
This is how a glass gage and a set of feeler gages are used to measure the XY coordinates of points along the facing curve.
November 12, 2018
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16. Facing Curve Analysis [cont]
Plots
These points should be plotted and a smooth curve should be draw through the points. In the plot shown, the X readings are exaggerated so it is easier to see the details of the curve. This is a plot I did back in 2003 for a client who sent me 4 mouthpieces to analyze. I tried to explain why each mouthpiece responded differently for him.
November 12, 2018
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17. Facing Curve Analysis [cont]
Radial curve formulation
Diagram
Formula
Compare to measurements
You can work off tables of curves you have measured from good mouthpieces. This is the “old school” method, but it works.
There are advantages in doing some mathematical analysis and using ideal facing curves. The radial curve is fairly simple and works very well for sax mouthpieces. In this formulation, “the facing curve” is the actual tangent point where the curve meets the flat table. In practice, the facing length is defined as the distance to the .0015” feeler gage. The tangent point would be the distance to a theoretical .0000” feeler. The radial curve passes through the tangent point and the tip opening. There is only one radius value that will do this for a given facing length and tip opening.
Spreadsheets can be programmed to fit and plot this theoretical curve through the XY points measured from the glass gage and the feeler gages. I have found that the closer I get to a radial curve, the more responsive and free-blowing a mouthpiece gets. This may not always be desirable, but it often is for sax players.
November 12, 2018
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18. Facing Curve Analysis [cont]
Theo Wanne’s “The Ring”
Polynomial formulation
Requires extensive data set
Theo documented a polynomial curve formulation on his web site that he calls “The Ring”. This curve can give good results but it requires the definition of many more curve fitting constants (Like 6 to 8 vs 2 needed for the radial formulation). This requires an extensive data set of measurements from good mouthpieces, which Theo has from his many years in this business.
I included this to show there are other ways of analyzing and generating facing curves.
November 12, 2018
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19. Facing Curve Analysis [cont]
Elliptical curve formulation
Diagram
Formula
Compare to measurements
Becomes radial when A = B = R
Good resistance when A/B > 1
See family of curves
This is my favorite general-purpose facing curve formulation. The elliptical curve still runs through the tip opening and the tangent point. But now a third term is added to describe the shape of the ellipse between these two points: the A/B ratio. This term is the ratio between the major and minor radii of the ellipse.
November 12, 2018
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20. Copyright 2009 - Mojo Mouthpiece Work LLC
In this plot, the top line (series 1) is for A/B = 1. So it is the same as a radial curve.
The bottom line (series 8) is for A/B = 8. It still passes through the tip opening and the facing length but it is shaped to make the reed bend more. This adds blowing resistance without changing the facing length or tip opening.
By experimenting with A/B ratios, you can come up with a curve that has the resistance of a short facing curve without actually resorting to a shorter facing length (which may have poor low note response). Some classical mouthpieces have short facings and high ellipse numbers (Selmers). Most of my clients like them better when I take some of the resistance out of them. (The ones who like them the way they are do not send them to me.)
Again, you can fit this curve through your favorite mouthpiece facings. Some will be a little off an ideal curve. But many will be close to one of these ellipses. There are a few good facings out there that do not follow these ideal curves (especially on clarinet). But there are many bad facings out there. If you take them towards one of these ideal curves, and do it well, they almost always play better.
November 12, 2018
Copyright Mojo Mouthpiece Work LLC

21. Facing Curve Analysis [cont]
Power of using a spreadsheet:
Graphical picture
Shows large measurement errors
Shows facing defects vs ideal curves
Helps create a plan
Shows refacing progress
Useful like an X-ray, MRI, Cat scan…
Plug in any feeler gage set and glass gage
Can change plan as you go
Overlay other curves that a client likes
If you look at your plot of a facing curve measurements, and you typed in a wrong number, it usually stands out a lot on the plot. The polt shows errors better than a table of numbers does.
The spreadsheet can generate a customized facing plan target for the mouthpieces. A little more open, more/less resistant, an appropriate facing length (you need to get a feel for what is appropriate for each tip opening).
As you work, you can plot your intermediate facing curve to show progress towards your targets.
Tables of numbers require you to stick with the same feeler gage sizes. A spread sheet programmed with ideal curves allows you to use any feeler gage set spacing that makes sense to you.
If you over shoot your targets, you can modify your plan to minimize the work you need to do to arrive at an alternate facing curve that is only slightly different.
You can take measurements from several mouthpieces and overlay them to help generate a refacing plan.
November 12, 2018
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22. Copyright 2009 - Mojo Mouthpiece Work LLC
Spreadsheet Example
These last three slides are excerpts from a spreadsheet I developed for my own use. This first part records some measurements before I start on the mouthpiece.
November 12, 2018
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23. Spreadsheet Example [cont]
This is the portion that I use while I rework the mouthpiece. The top line is the plan to open up the tip of this mouthpiece from .096” to .105” while holding the facing length where it is at about 46. The tip is crooked (twisted) as shown by the .093” feeler readings. I show this exaggerated (times 10) on the plot with the points connected by the dotted lines. This helps me by drawing attention to these problem spots.
During the clinic I changed some of the numbers to illustrate in real time how they show up on the plot.
November 12, 2018
Copyright Mojo Mouthpiece Work LLC

24. Spreadsheet Example [cont]
This last slide shows the portion of my spreadsheet where I document what I did for the client. It is an easy way to keep records and to generate a receipt for the work.
November 12, 2018
Copyright Mojo Mouthpiece Work LLC