I used to use a step reamer,but sometimes the step would be too big or too small,making the prop not fit snug on the crankshaft.
Being an ASE/GM auto tech,I had a tapered reamer in my toolbox at work that I rarely used.
I brought it home a tried it on some old props to see if it would do the job.I have to taper the front
and back of the prop hole,but I can fit the props perfectly to any size crankshaft.
Here is an example of the reamer I am using.

http://www.outsideoutfitters.com/p-2...ed-reamer.aspx