I have three metal Berg Larsen tenor mouthpieces (stainless 110/2/M 
bullet, stainless 90/2/M bullet, brass 115/2/SMS straight baffle).  On 
all of their facing curves , the measurements from the .0015 feeler 
through about the .063 are low (compared to the plot for a radial 
curve), generally by .5mm-1mm.  Their tip openings measure smaller than 
they're marked, but I used the actual measured tip opening when 
calculating, so that shouldn't be an issue.  I also noticed that the 
facing measurements recently posted for some Florida Links refaced by 
Jon van Wie indicate a similar shape - leaving the table more gradually 
than a radial curve, and (presumably) curving a little more sharply near 
the tip.  I've read the posts about elliptical facings and the more 
severe "flip tip" configuration.  Are these all possibly elliptical?  Is 
there any consensus on the possible advantages of this slight deviation 
from radial?  Resistance changes?  Any other insights?  I'm still 
working on executing my measurement targets consistently and accurately, 
so I'm not up for tackling this kind of subtlety just yet, but I am 
curious about it.  Thanks.

Dan

--- In MouthpieceWork@yahoogroups.com, Dan Torosian <dtorosian@e...> 
wrote:
> I have three metal Berg Larsen tenor mouthpieces (stainless 110/2/M 
> bullet, stainless 90/2/M bullet, brass 115/2/SMS straight baffle).  
On 
> all of their facing curves , the measurements from the .0015 feeler 
> through about the .063 are low (compared to the plot for a radial 
> curve), generally by .5mm-1mm.

By low do you mean longer or shorter facing curve?  I think you mean 
longer, which are higher numbers.

>  Their tip openings measure smaller than 
> they're marked, but I used the actual measured tip opening when 
> calculating, so that shouldn't be an issue.  

The spreadsheets can be used to make a variety of facing lengths for 
any tip opening.  Longer facing curves just need a larger radius.

>I also noticed that the 
> facing measurements recently posted for some Florida Links refaced 
by 
> Jon van Wie indicate a similar shape - leaving the table more 
gradually 
> than a radial curve, and (presumably) curving a little more sharply 
near 
> the tip.  I've read the posts about elliptical facings and the more 
> severe "flip tip" configuration.  Are these all possibly 
elliptical?  

Some of the posted Link facing curves have bumps and flat spots in 
them.  The points do not lie on a smooth radial or elliptical curve.  
Some may consider these as desirable features.  I consider them 
facing defects.  Curves with "flip tips" do not lie on a smooth curve 
either.

This html message parsed with html2text ---------------------------Keith,  
  
Indeed, upon further scrutiny, my little theory doesn't seem to hold up.  
  
I think I understand the spreadsheet - it generates the unique radial curve
which fits a given a tip opening / facing length combination. These three
Bergs (and the JvW Link measurements posted) measured _shorter_ at the "table"
end (small feelers), with the measurements gradually catching up to the
"radial targets". I thought I saw a pattern - a more gradual (flatter-than-
radial) curve near the table, then a sharper curve towards the tip (to get to
the measured tip length). If there was a _consistent and gradual_ deviation
from radial, this might be a deliberate facing plan. BUT..., I noticed that,
on one mouthpiece, I had mis- copied one number, making the deviation look
smooth when it wasn't. Another followed this pattern (below) but looks more
like it just has a high spot (the decline in the "Diff" numbers is not real
consistent), and the third was not even this consistent. So the evidence is
thinning... One thing: they all measure significantly shorter than the radial
targets near the table, as do the posted JvW Link measurements. This made me
curious, but it looks like I just have a couple of mouthpieces with similar
bumps and flat spots.  
  
_Feeler_ _Radial_ _Measured_ _Diff_  
.0015 50.0 50.0 0  
.005 44.4 40 4.4  
.010 39.4 36 3.4  
.016 34.8 31.5 3.3  
.024 29.9 28 1.9  
.035 24.3 23 1.3  
.050 18.0 17 1.0  
.063 13.3 12.5 0.8  
.078 8.4 8.5 -0.1  
TIP: .102  
  
  
  
Keith Bradbury wrote:  

>
>     \--- In
> [MouthpieceWork@yahoogroups.com](mailto:MouthpieceWork@yahoogroups.com),
>     Dan Torosian [](mailto:dtorosian@e...) wrote:
>

>>

>>     I have three metal Berg Larsen tenor mouthpieces

>>     (stainless 110/2/M bullet, stainless 90/2/M bullet, brass 115/2/SMS
straight

>>     baffle).

>  
>  
>     On
>

>>

>>     all of their facing curves , the measurements from

>>     the .0015 feeler through about the .063 are low (compared to the plot
for a

>>     radial curve), generally by .5mm-1mm.

>  
>  
>      By low do you mean longer or shorter facing curve? I think you
>     mean longer, which are higher numbers.
>

>>

>>      Their tip openings measure smaller than they're marked, but I used

>>     the actual measured tip opening when calculating, so that shouldn't be
an

>>     issue.

>  
>  
>      The spreadsheets can be used
>     to make a variety of facing lengths for any tip opening. Longer facing
> curves
>     just need a larger radius.
>

>>

>>     I also

>>     noticed that the facing measurements recently posted for some Florida
Links

>>     refaced

>  
>  
>     by
>

>>

>>     Jon van Wie indicate a similar shape - leaving the

>>     table more

>  
>  
>     gradually
>

>>

>>     than a radial curve, and (presumably)

>>     curving a little more sharply

>  
>  
>     near
>  
>

>>

>>     the tip. I've read the posts

>>     about elliptical facings and the more severe "flip tip" configuration.
Are

>>     these all possibly

>  
>  
>     elliptical? Some
>     of the posted Link facing curves have bumps and flat spots in them. The
> points
>     do not lie on a smooth radial or elliptical curve. Some may consider
> these as
>     desirable features. I consider them facing defects. Curves with "flip
> tips" do
>     not lie on a smooth curve either. \------------------------ Yahoo!
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>     .

It is common for the .0015" feeler to give a long facing curve measurement
while the rest of the curve does not.  I think this is from overshooting
the facing curve target and/or wear.  Just dragging the mouthpiece over a
table top a few times can alter the .0015" reading.

I would recommend that you try ignoring the .0015" measurement when fitting
radial curves to your measurements.  Then your fitted curve will tell you
what the .0015" target should have been.



		
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