So, it's the day before SKN and no straight key! It's off to the junk-box. Ah, an old piece of aluminum from a scavenged torsion bar discarded from a veneer clipper at work, this will work nicely for a base.
And, a micro switch should work instead of open contacts, just need to attach it to a plate with slotted holes for adjustment then fasten to the base with machine screws.
The arm, I can cut from fiberglass pc board, fastening a knob on the end will make a good finish and will feel close to the real thing.
Preparing the base for a micro switch.
The key arm to actuate the micro switch is cut from a piece of salvaged fiberglass pc board. Stiff but flexible enough for a good feel.
Now, I'm all set for SKN!
The finished piece doesn't look like much but it is very functional.