I just had an interesting email exchange with a couple of people about
the rope or cordage used to hold the moveable board in a dual set of
pressure pumps tight against the pocket in which the moveable board
pivots.  Nylon hadn't been invented yet.

That brings to mind the question of what material the stiffeners inside
pressure pumps used to be made of, and the secondary question of what
material it would be best to use for stiffeners today in this age of
plastics and resinated board of various types.

Your opinions on these questions are invited.

Matthew Caulfield
Irondequoit, New York