CNC RC Motor Spindle

[jjr2001]

The point here is if you buy an inexpensive import ER-20 or any other type of shafting make sure it is true by chucking it up in the lathe and checking it for runout. It may just save you a tear down!!!

In the first post I noted the .002 runout and have since found that I was lucky to get that low. I had a poor collet and in addition the shaft was defective from the overseas factory. The luck was in angular placement of the collet in the shaft. I measured .003 for the runout of the shaft and about the same for the bad collet. When put together at the real lucky position run out was better than .001.......At worst it was.006....Yikes.

Could not live with that. Destroyed the bad collet. Disassembled the shaft from the bearings and housing. I had found that the shaft OD was better than .0004. However the taper for the collet was .003.... Ok, lathe time.

Chucked up the shaft in my lathe and indicated it to better than .0005". Then I used a dial test indicator to set the compound to the taper of the shaft collet socket. When I had the angle right for the ER-20 taper I put my dremel on the tool post with a small grinding wheel and took very light passes on that ugly taper. You could hear the runout as it was turning. Eventually after about 12 passes the sound became quite steady and I knew it was done.

Testing on the lathe with a dial test indicator showed no movement in the indicator.

Result after putting the spindle back together was better than .0005 runout. Now that I can live with.

Cheers, JR