kimric said:
This is almost essential for cutting layered valves. I found that it is difficult to cut them with scissors or a table cutter as the layers want to slide around on each other and the the result is not consistent (this explains all the clamps). I do not have to make valves very often but I have to cut and then assemble them. This would be nice for cutting pads too but I pretty much have that worked out.
I have never cut through multiple layers so far. I have layered (plastic) valves in many different sizes, so if a valve is a bit too long I cut a bit from the (loose) end of the bottom layer, and in a few cases also a few mm from the end of a second layer. What I use most are leather valves which are only a single layer. I wouldn't want to cut from the other end because that's where the layers are glued together.
I have never considered making my own valves from different layers of plastic, and also not considered cutting through multiple layers as needed to make a valve narrower. With so many different sizes of valves being available, why would you consider making your own valves that require assembling layers?