Bridgepins
AlCarruth@aol.com
Thu, 20 Jun 1996 06:40:27 -0400
Mike will probably have something to say on the matter, but I thought
I'd get in my two cents' worth.
My take on harp history has the stave-back, 'romantic', Gothic harp
coming after the 'heroic' Celtic instrument. The Celtic harp had a removable
back for string changing, and used some kind of harpknot/toggle arrangement
to keep the strings in their places. Gothics tended to be very light, and the
lute-like staved back would have been too weak if left open. Also, because of
the small size, the sound of the Gothic doesn't carry well. The solution was
the 'bray pin', a tapered pin with a flag-shaped top. The pin in the hole
keeps the string in, and the top is trimmed in such a way that the next
(higher?) string buzzes against it, like a sitar bridge. This introduces a
lot of higher harmonics to the tone, at frequencies where the ear is more
sensitive, so that the sound carries. The vaulted back/ pin retainer system
caught on because it was lighter than the square back, and thus allowed for a
larger instrument. It is my understanding that pins were more or less
standard in harps until fairly recently (early 20th cent.).
I believe that the guitar actually picked up the bridgepin idea from the
harp. Early guitars all used the lute-style tied bridge, which is retained on
the modern classical guitar (with the addition of a separate saddle). Pin
bridges probably caught on because the builders were familiar with them, and
they facilitated quick string changes.
Fitting bridge pins is a vexing problem. They should NOT fit too
tightly, as the wedging action will tend to split the bridge/ stringbar. The
idea is that the ball or knot on the string end pushes sideways against the
protruding inner end of the pin, and that side force holds the pin in place,
while the pin in the hole keeps the knot from pulling through. The pin should
just 'set' in the hole without the string in place, and the hole or the pin
(or both) should have a groove the size of the string. Part of the problem
with old harps may be due to smaller strings being used, as well as
shrinkage, etc. Also, bridge pins are like valve lifters, they have to be put
back in the original hole. Once they get switched around it is hard to put
them right. Bone, ivory or wood pins hold up better, as the plastic ones tend
to deform over time.
As an aside; plastic was actually invented as a replacement for ivory.
So many elephants had been killed to satisfy the demand for billiard balls
that the price of ivory was going through the roof just as billiards was
becoming really popular. So a way was found to use nitrocellulose (which, as
rayon, had been made in the form of fiber as a silk substitute) in bulk form.
It was often made with a grain pattern to imitate ivory. At the time it was
hot stuff, very high-class.