When doing valves in a player piano, remember that when the valve
seats against metal plates that you use smooth leather with no nap.
Valves seating on wood then use leather with a nappy side.  I will
admit there can be exceptions.

The valve travel should be 0.035" in most players.  Simplex style
it is 0.028".  Those are valves that are covered in pouch leather.
The tightest stack I ever had was a Simplex.

Don Teach
Shreveport, Louisiana