[pianotech] hammer boring jig

[jim ialeggio]

I've been meaning to post photos of a hammer boring jig I worked out. It
uses an "off the shelf" cradle style drill press vise... cast iron,
relatively inexpensive ($60 Palmgren Vise  @ ENCO) .

The trick was figuring out what the cradle's axis of rotation was.  I worked
out the geometry, and "proved" its axis of rotation to within .005".

By setting it up the way I have it, using very simple arithmetic I can
quickly add shims to the fence and/or hammer molding base to place any width
of hammer or any molding thickness dead on the axis of rotation.(I generally
measure the variation in hammer thickness on samples from the set and decide
on a mean value).

I'd be happy to share the geometry needed to set this up with anyone who's
interested. Comments and improvements welcomed!

At present it's not set up accommodate non-90 deg rakes. I think I know how
to do that, but its not something I anticipate needing right now...so
modifications are on a back burner...or rather, well, not really on a burner
at all.

The fence is not set up with a stop, since my process starts by boring to a
drawn line on the molding.  A fence with a stop would be easy to work out.

Jim I
-- 
grandpianosolutions.com (under construction)
Shirley, MA  (978) 425-9026
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