damper-wire slap

[Mark Cramer]

 I'd been putting off trouble-shooting some rattly bass notes on a new belly
job for several months. With all the action work complete and regulation
almost done, opportunities for some hard-core procrastination were rapidily
diminishing.

Apparently an all too common cause for procrastination is "lack of
information." That's where I was at; I didn't know the cause of the rattles,
so I put it off.

The rattling was present in a number of strings, mainly over the transition
from singles to doubles, and just from a 'forte' level on up.

It sounded like damper-wire contact, but it wasn't. Trouble-shooting took me
through muting back lengths, twisting a string and finally to removing the
dampers, though there was visibly ample clearance from the wires.

The cause turned out to be lack of downward termination angle from the
string-rest to the aggraffes. I just noticed this during a prolonged,
beleagured stare at the trouble-area, while mentally pleading for the cause
to make itself apparent.

The string passed through the aggraffe from front-to-back without deviation.
When I lifted the string segment between string-rest and aggraffe with a
hook, and pounded the note, the rattle was gone.

I have been in a habit of "reconditioning" aggraffes (if new ones don't
match the threading)  including re-sizing the string holes.  Hmmmmmmm!?

More likely the culprit however, is the fact I replaced the original string
rest with new material, probably with no regard for the original thickness.
(ooops!)

The rattles are gone!

Though I would've liked to bolster the string rest with thicker cloth, or
add a continuous bearing bar, the simplest was to insert bridge pins under
pairs of singles and double-pairs of bi-chords, to support a sufficient
termination angle.

Did I mention the rattles are gone? :>)

Mark Cramer,
Brandon University