Vertical Hammers

[BobDavis88@aol.com]

from Warren Fisher:
<< All the vertical hammers I've replaced so
 far have had 5-10 degrees of downward angle (rake) at rest to compensate
 for flexing of the shank on a hard blow.  This means at normal play they
 don't strike at exactly 90 degrees.  The most important concern is the
 correct strike point on the string, because that causes the most
 effective and powerful beginning of the vibration pattern and harmonic
 generation for that string!  Just a tiny bit off on either side will
 make the note sound muddy.  I'm sure you've noticed that test blows
 while tuning don't sound as clear as when you're just playing the note.
 It's because the hammer is striking above the strike point!  >>

Warren -
My understanding is that the rake on vertical hammers is so that the shank
will be behind vertical when the hammer strikes the string, which causes the
weight of the butt/hammer assembly to be centered farther behind the flange
pin, which makes the hammer more willing to "fall" back, aiding its return. I
also suspect (without denying that the strike point changes a little on a
hard blow) that the muddy test blows could be caused by sideways motion of
the hammer, causing it to catch the edge of the grooves. If I'm right, you
will hear this change of tone in the tenor and low treble, where a 1 mm
change in strike point doesn't make an appreciable difference. I'll also bet
you'll find this effect less evident on ungrooved hammers.

Bob Davis