I belong to a number of Yahoo Groups besides this one, among them, 
the Bass Sax Coop.

Joseph wrote:

 Hi,
a community college here has a Keilwerth bass sax (purchased 2005) 
that they thought was in poor repair, yet no one had the time to 
take it to a good repair person. I volunteered only to find out that 
there was nothing wrong with it! I used my Lelandais bass mouthpiece 
to try it out and it played quite well, a few odd intonation things, 
but otherwise fine.
 
Then, I put on the stock Keilwerth mouthpiece and it played 
HORRIBLE!  The low register barely spoke, gargling mostly. The upper 
register wasn't so bad. 
 
I've been reading so much about the Zinner mouthpieces lately in 
the forum. Would any of those be a good match for the Keilwerth? Any 
other recommendations?
 
Anyone to reface the Keilwerth mouthpiece?
 
Thanks so much!
Joseph

I had emailed Joseph, told him to send the Keilwerth mouthpiece to 
me, and I would check it, and post the facing measurements, and 
reface if I thought that would help.

Joseph sent the mouthpiece to me and upon measuring it, it was 
immediately apparent why it would not play the low register...
the facing was too short.  In fact, it would have been short if it 
had been a baritone sax mouthpiece!  The facing was only 24 mm long, 
with a tip opening of .102".  Also, the table was uneven, though the 
rails were even from side to side.

I flattened the table, then worked on the facing curve.  Here are 
the before and after measurements:

Feeler-----------Before------After 
.0015"(.04 mm)-----24---------30 (mm's from tip)
.010" (.25 mm)-----19.5-------23
.014" (.35 mm)-----18---------21
.024" (.6 mm)------15---------18
.031" (.8 mm)------12.5-------15
.048" (1.2 mm)------9---------11+
.063" (1.6 mm)------6----------8+
.077" (2 mm)--------4----------5.5
.094" (2.4 mm)------2----------2+
Tip Opening-------.102"------.102" (2.6 mm)

I am sure the Keilwerth bass sax will now play in the low register 
with this mouthpiece.

Paul Coats