Tom,
At 13:37 04/18/2000 -0400, you wrote:
>OK Ed and Newton, I'm not sure I understand yet. Greater bearing
>area......hmmmm....OK then, why not have a larger diameter round pin?
I'm not Newton or Ed, as they would be quick to point out, but...
A larger diameter round pin would still have to fit in the mortice. I
don't know what the radius of the bearing surface is, but I'd bet that a
round pin with that radius would be wider than a sharp key.
If you think of a small round pin bearing against a flat bushing as being
tangent, then the bearing surface is an edge and very quickly would cut
through the cloth. Actually, it starts out as an edge, but as it wears
into the cloth it contacts more and more surface. More surface contact
area means a slower wear rate since theoretically you aren't putting any
more sideways pressure on the key. (i.e less psi since there is more si).
So... the oval pin (batpin to some, since it resembles a cricket bat)
starts out presenting a larger wear area and thus longer wear time, while
still fitting inside of a normal width key.
Conrad Hoffsommer - mailto:hoffsoco@luther.edu
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