[BoilerMentor]

Originally Posted by Richard Wallace

I agree with all your points regarding proper interference fit, and reaming is clearly a better method. I think we just got lucky with the #9 drill. Over the past 30 years, I have press fit a lot of motor shafts from 2mm through 17mm diameter and have developed a feel for the forces involved, so I am pretty confident of the results we got on a few motors. I would not use the same method in serial production.

To your question: I'd go with the 0.1955" ream. We will probably do the same when I need to make more components.

Thanks for the input. I'm afraid in the process of removing the improper pinions we may have damaged our motor set, so my intent is to use the .196" drill for this first set of questionable motors to be used in program testing and development, then put in our order for a competition set and back ups for those at which point we may go ahead and get the reamer and take that time.

For anyone wondering, the reamer is McMaster part number 8803A32. You have to specify that you want the .1955" from the range associated with that part number.