While OT, know several here have odd side interests, too... :)
Am putting an old piece of farm gear back into service for special purpose and salvaged the PTO shaft from a (very) old tractor-drawn sprayer.
It is old Blood Brothers of Michigan shaft; 1-3/8" 6-spline on the one end (which is good, what need) but a 1" round female drive on the other.
Is 1" sq shaft w/ the offending end on the larger sliding hollow square shaft. Ideal would be a replacement half of the u-joint w/ a 6-spline to simply replace the round altho I suspect there's no source for Blood Brothers repair parts any longer (at least I've not found any).
Second best would be a square complete u-drive to replace that end; no joy on the square drive.
I can find a 1" F round pump adapter to 6-spline; that requires another loose 1" shaft that would like to avoid if possible.
So, the question would be has anybody seen a 6-spline to MALE 1" rd adapter instead of female???
Just a wild chance perhaps somebody else here has been doing something peculiar... :)
--