Homebrew cootie key.
I have a Bunnell cootie key but prefer the homebrew model I put together in 1985 from spare parts I had laying around here. It is built in the form of a bug on a 3 by 5 by 1/2 inch heavy iron base with 3 rubber feet, but without any vibrating parts on the dot side. Instead, I put a dash contact on both sides. Unlike the Bunnell and other similar hack-saw keys it has a definite off position, not an undetermined center area. I can adjust the length of the thumb and finger throws, although I don't think they matter as much as I thought they would.
I also have a cootie made from a hacksaw blade with dash contacts on both sides. I also have a cootie made by bolting two straight keys base to base and setting them up at 90 degrees. All three of these cooties work OK but none have the nice feel of my HB model. [W6BNB].