Looks like I might have a use for relays with my #The Cardboard Computer - IO is my name project after all.   I am looking into ways to interface IOs output to a converted typewriter and need isolation while still using materials/parts that are on hand here in my secret lab :-) Need 16 SPST relays, just need to get the coil current demands down to a manageable level.

Here is the coil for relay number 2. Using double thickness of cardboard at each end and turned 90 deg. for strength.

Here is the result the morning of March 21, 2018...

The counter weights for breaking the contact will be replaced by a spring or rubber band. Better core material is on the horizon.

As of this afternoon, IO and the printer both are using the relay as isolation and working well.