composite block warping

[Bob Hull]

Ron,

> --- Ron Nossaman <rnossaman at cox.net> wrote:

> I look at the plank to see which side has the
> thickest outside lamination, and that side goes on
the bottom. I the saw and plane the top to what my
overall thickness minus the
> cap will be, and laminate the cap on, with the whole
mess clamped to a  flat plank. Measure and a final
touch-up pass through the planer (off the bottom) the
next day if necessary,
> and that's it. If they aren't dead flat, I haven't
found it to be more than a minor annoyance, and I'd be
surprised to find a plate with a dead flat webbing in
any case. The only top fitting I do is at the bevel
going from the flange out onto the webbing in come
pianos, or if there is some casting anomaly
> to get around, and that's only for minimal
clearance. It's not particularly well fitted.
> 
> Ron N
> 

Thanks, we'll look at doing the next one that way.

Was there some discussion about sandwiching the
multilam between a delignit top and bottom?  I didn't
find it if there was.

Since the delignit provides excellent pin support at
the top with it's density, and the pin tilt change
possibility would effect both ends of the pin,
wouldn't a similar density to support the bottom of
the pin be desirable?  

It seems like this might balance the structure of the
block and maybe prevent the warping - or make it
worse??

Our first capped block turned out with the torque to
high.   Our second, with same size bits (1/4 and
17/64) turned out too low - 100 or less inch pounds. 
We didn't use that block.  We experimented with
different bits before the next block.  The 1/4 and
17/64 seemed a little to tight with 170 to 180 torque.
 So we used 1/4 and H on the next block - but the
actual work didn't yeild results consistent with the
experimentation.  We have only fair results with this
one with 120 - 140 torque but some lower.  I told
Richard to do more coil and becket work while the pin
is higher out of the block rather than driving it down
too close and working the pin back and forth.  Bought
a new drill press too since the other seemed to have
wobble up in the quill.  
Still I'm not real satisfied.


One thing I think we remembered that probably made
that first block come out so tight was that we had to
make plate bushings for that one.  These were made
from oak and were really tight for the pin.  Probably
contributed to the higher torque.  

Bob



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