I am modifying my amp by installing a Johnson 226-3 roller inductor in the tank circuit. It has a 3/8" shaft and I am trying to mate it with a Johnson turns counter, which has a 1/4" shaft. I have searched thru my junk pile and cannot come up with a coupler. Anyone out there have a spare 3/8 to 1/4 coupler? Thanks, Bob W6TR