Wapin bridge

[John Delacour]

At 6:48 AM -0600 1/24/02, Cy Shuster wrote:

>I'd type more of the liner notes, but they're copyrighted.  A key point is
>"a vibrating string in a piano takes on a substantial movement in the
>unstruck direction shortly after it receives the blow from the piano
>hammer."

The first thing I noticed on visiting the Wapin site was the extreme 
angle of the non-perpendicular pin in his background logo.  There are 
pianos where the pin angle is quite marked, but this has never been 
the rule for all makers.  Two Lipp pianos I am working on at the 
moment, and all other Lipps, which of all pianos I know are worthy of 
the "golden toned" epithet and which sing strongly right up through 
the treble, have the bridge pins at a very small angle to the 
perpendicular compared to most pianos; besides this the pins are 
unusually high, protruding six or seven millimetres from the bridge 
face.

As usual, Wapin's comparison is made with Steinway as the benchmark 
and his wave patterns compare an unmodified Steinway with a modified 
one.  I have had more trouble with poor singing quality in the 
Steinway treble than most makes except the Bösendorfer, most of which 
have a terrible decay problem.

It strikes me that the main thing about the Wapin arrangement is the 
near perpendicular disposition of the front pin.  Without reading 
right through the patent I can't be sure if he says anything about 
the way the "bearing point edge" is cut and whether a small vertical 
drop is desirable (a feature Wolfenden admires in the practice of one 
maker, probably Ibach) or whether this angle should be at least 
steep, as it certainly is not on the Steinway.

The "a third pin" of the "preferred" arrangement is a secondary item 
in the patent claim, so the main thing is the perpendicularity of the 
front pin.  Now it is not necessary to repin the bridge to achieve 
this effect but simply to file the front pin perpendicular for the 
first <1.5 mm of its height, and this could easiy be done using a 
suitable small diamond file in combination with a feeler gauge to 
avoid damage to the bridge face.  It would be quick and easy to test 
the effect on a less than crucial restring job.  The addition of a 
third pin, if it's worth it, would be a simple matter.

It is quite likely there is some sense in the Wapin arrangement, but 
I think the bridge cutting and the position of the pin in relation to 
this is also most important and it's quite possible that the height 
of the pin above the string also has some effect.

Bad contact at the bridge or the stud can, as we all know, have very 
bad tonal effects, and the first thing I do with any piano that comes 
under my care is to knock the strings down on the bridge, thus 
removing almost always some of the worst tonal problems the customer 
is complaining about.  I imagine that with a perfectly vertical pin, 
this bad coupling problem wight need to be dealt with more 
frequently, but that's just guessing.

JD