composite block warping

[Ron Nossaman]

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

Bob,
I think it was mentioned, but not considered to be necessary.


> 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?

If the bottom of the pin actually reaches the dense layer, I 
wouldn't, unless you like jumpy pins. Why not just use a 
Delignit block? Incidentally, there is very little stress on 
the bottom of the pin. It's concentrated at the top of the block.


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

It might prevent warping. I don't see how it could 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.

This, I don't understand. I've gotten extraordinary uniformity 
with these blocks and double drilling, and I'm doing the 
second pass at 6.8mm, which is 0.2677", or 0.002" bigger than 
the 17/64. I've not had one end up anywhere near loose. 
They've all been very tight, probably too tight for some 
tastes, but even tight, they're very controllable.

That SD-10 was drilled at 6.8mm, with 2/0 x 2 3/8" pins, and 
was very characteristic of how my blocks feel. What did you 
think of that one?


> 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

Mine are somewhere in that range normally, without bushings. 
Again, I don't understand.
Ron N