What had to be machined to get it working?
I think it would be safer if the external splines were removed or covered with a cylinder but that is probably not necessary due to its location.
Will you be able to slide it forward to replace the fan belt or will you have to basically remove it?
That is a clever solution though. Where did you hear about that part being in existence?
Well, long story long...
My year B7100 does not have the bolted flange on the crank pully, only about a 1/2" spline stub sticking out the center. Kubota made an adapter for this stub to size up to the magnetic clutch pully/shaft for the PTO for the belly mower that was an option my year.
The pump I purchased had a 1/2" keyway shaft and you can buy Lovejoy couplings in any size combo seems like. I found one that went from 1/2" on the pump end to 3/4" keyway on the drive end, the reason being, 3/4" gave me material to turn down a shoulder on the shaft, and turn a pocket inside the end of the spline adapter. I was able to achieve a concentric press fit between the modified spline hub and the shaft and mate them fairly precisely, finally welding them.
I realized I had to turn off the bolted flange on the back end because of clearance issues. I wanted to be able to remove the shaft for belt changes without removing the radiator every time. I do have to remove the pump but that's only 4 bolts. I'll take a picture the next time I'm able.
Regarding the Kubota spline hub existence? LOTS of digging through forums, Kubota parts diagrams, and looking at old auctions for the belly mower PTO attachment. I had the spline on the crank hub, so I figured there was something out there.
Thanks for the compliment! I was worried that I had screwed myself when I realized that there was no OTS part even close...
Regarding safety, the shaft is buried between the radiator and the frame rail, though I do need to fab a cover for the shaft and the pump. That or at least get one of these terrifying stickers...