Report on Otoscope

[Wimblees@aol.com]

I have a question regarding what one could see inside the tuning pin hole
with an otoscope, or ohter magnifying glass.

We can see delaminations on the bottom of a pin blck. We can even see cracks
in the bottom layer. However, a lot of "bad" pin blocks have cracks in the
lamination that are in the middle layers, or the top layer, (the top layer
being up against the plate). If you were to look at the side of pin block
where a crack in one of the middle layers would come out, you would see only
a small up and down line.

With this in mind, when you look into a tuning pin hole, to inspect it for
cracks, wouldn't you be looking for small lines, up and down, in the layers,
instead of seperations between layers?

Willem Blees  RPT
St. Louis