Welcome to ModelEngineMaker !If you have problems registering or logging in, please use the contact menu option to request assistance.
Hugh, Many things have changed since ED & I used wire drives back in the 1980's. The collets we used operated at approximately 7 HP & 30,000 RPM. I posted some photos of these. All the parts were made of AISI-01 tool steel. The split collets were hardened to a spring temper. The collet seats were full hard 01 steel. They typically had .0002" total indicator runout 1.000" from the collets nose. They lasted indefinitely & they worked on both hard shafts & cables. I cannot say if they would work at present day FE RPM's & torque. ER type collets are presently being used, some on gas boats & some on FE SAW boats. ER collets come in fractional sizes (.0156" increments) & typically have .0002" runout. They require smooth, round, straight, hard shafts at the motor end. Piano wire will not work! I am told that FE SAW boats operating in the 60,000+ RPM range are using a single piece coupler with saw slits. These things have a run out of less than .0002". I'll see if there are any photos to upload.There is also a single piece coupler with slots that is supposed to have less than .0001" runout. It is shown on INTLwaters & it is preferred by some FE SAW boaters.Jim Allen