I am working on a H. C. Bay upright that has been worked on before,
and poorly.  I am looking at the span on a striker pneumatic and it
is all wrong, but not sure what is correct.  The boards are 1" wide.
The material currently on them is 1-5/8" and goes past the center
from both directions when you try to close it, which you can't.

As a test I took the width of the pneumatic plus the thickness of
both boards, added the together and got 1-1/4" for my material width.
This gives me a nice fold right to the middle of the pneumatic.
Although this will work, my question is;  Is there a actual formula
for figuring the correct material width?

Bob Stewart
Denton, Texas