- Oct 30, 2018
Grubee's OCDT sprag clutch uses a one-way bearing, either "csk-15pp", or, what they say is better, the "CSK-17PP 6203" version, both of which are cheap and available on eBay. I suspect the tool may be is custom machined by Grubee. They sell it for $39.95 + shipping. I don't see such a drill attachment being sold anywhere else. (Here is a recent patent application for the idea, not by Grubee, for a similar drill attachment to start a model airplane engine via a nosecone spinner. PDF) It's pretty cool, but I don't need electric start that badly. It isn't entirely necessary just for a start though. Just a little more safe. One could easily sprain a wrist or worse without it, but I've watched Mustie1 do it SOOOO many times...EDIT: I found their instructions page for using the overrunning clutch tool on a drill. There they say to remove the allen head screw and apply blue Loc-Tite. I suppose that might be sufficient. The compression on my little motor seems pretty high to start it this way. But I may give it a try. Cool.