CA gluing Grand Pinblocks....My take on it/ Richard Brekne

[Richard Brekne]

Terry, and others following along.

After reading back and forth a few times I find myself in
agreement with you on everthing except this one point about
what happens when glue comes into the picture. You seem to
be saying that when there is glue present between the bridge
pin and hole then some shear stress is present that isnt
there without the glue present. A couple posts back you said
:

"..., if the pin were also glued to the wood in its hole,
until the glue completely fails, there would be a shear
stress between the pin and the glue and the wood on the
forward and rear side of the pin (where the pin would be
sliding past the stationary wooden bridge during its
migration)."

Thats where I get confused. The direction of the force from
the string is the same, as is the resistance from the
bridge. The pin still stands more or less perpendicular to
these. The only thing that has changed is a thin layer of
glue between the lengthwise surface of the pin and the
inside of the bridge pin hole.  I think you are saying that
at the very top of the hole, half the pin/glue/wood surface
is under shear stress, and the other half is under
tension/compression,,,. But if this is so, how significantly
does this change the total picture, and how does any of this
figure into bridge cracking ?

Just about there methinks :) I think I read you clear now on
the rest of it.

Thanks for your patience Terry. :)

RicB