I have been looking for a valve like they use in the vacuum pad clamps
(used to hold work to a workbench) sold at the woodworking shows.
They shut the vacuum off when a workpiece is removed from pad. The
pads they sell are quite nice, but expensive and I have built these
pads (without the valve), but I would like to have this added feature.
I have looked at Grainger (no luck) and Vacuworld (who call them
touch valves and want over $20.00 for them). I think the function
should be able to be done for under $5, but have not been able to find
one yet. Anyone ever find them? Any ideas would sure be appreciated.