Anyone know what kind of tool used to bore a prop? From 3/4 Hex to 7/8 threaded.

I wouldn't be surprised if there's not enough material there to get the proper depth threads. Assuming, the hex is measured on the flats and not the points.

that right, the hex is measured from the flats, so that doesnt leave enough left to thread

if ya run a tap in it if it cuts the threads at all they will not be any in the corners because that diam. is not right

You don't bore it to 7/8". You bore it smaller then, cut the threads. The threads are 7/8" at the deepest part in the hub.

Measure the hex hub, point to point and get back with us.

Kibb, Point to point i got 7/8. Square to square i got 3/4. Which leaves 1/8 of an inch for the threads ??

It wont work as Craig stated. You wont have threads all the way around. Even where the flats are you wouldn't have enough thread depth, but go ahead and try it and tell us how it turns out. We know you are going to do it anyway.

Depends on TPI.

Threads per inch. The TPI would have to be identical so you would be cutting the old ones down and deeper.

1/8" will be a lot to cut at one time with a hand tap, even if they are the same. Find a chart online and drill the threads out to spec and tap from there.

better make all your holes and threading straight or you are going to have some horrible vibration going on and things coming apart on ya. Buy a new prop and save the money you will be spending if that prop ends up tearing stuff up cause of bad vibration.

I had Baggy convert a hex bore prop to a taper bored & keyed and ended up costing as much as a new prop. The had to bore it, install and weld an insert and then do the machine work. So to answer your question YES it can be done, just ain't real cheap.