my own Soundboard

[Ron Nossaman]

>
>  This idea came to me directly from uncle Ron N before I glued in no. 003
> sound board. We undercut the outer-lower edge around the perimeter to prevent
> any excess glue-squeeze-out from gluing the former to the sound board. This
> single piece device allows for clamping up much faster than using individual
> blocks for each clamp. 


And I in turn, got the idea from Shawn Hoar in one of his thoroughly wonderful
and utterly terrifying convention classes on shop tooling (toys) and
techniques. I still use spacer blocks as well as the caul. The blocks are
necessary with F clamps because the clamp screw isn't long enough to reach the
depth of the outer rim without them. At lease mine aren't. My thinking is that
the plywood caul distributes clamp pressure so you get good clamping uniformity
with fewer clamps and blocks. With the blocks spreading the clamp load, and the
caul spreading (less efficiently) the block load, you handle fewer clamps for a
given size piano and it clamps up pretty quickly. I've even glued corrugated
cardboard to the bottom side of the perimeter caul as a pad. Works fine. 

My blocks are 15cm wide, and from 10cm to 14cm tall, with an arch relief cut
out of the bottom center so there are two 35mm "feet". Eyeball spaced around
the piano rim at 8cm or so apart leaves the clamps about 20-25cm apart. I think
I get good clamp pressure distribution, more then adequate clamping pressure
for the glue line, and can still get an arm between the clamps for adjustments.


You go with what you think you know and be prepared to re-think and re-tool
when you find out differently, as do we all. I find I'm a fan of F clamps in
general, and this system works to my satisfaction for installing soundboards,
so I apparently guessed close enough... for now. Tomorrow's always another day.

Ron N