Originally Posted by
3alarmer
...if you're talking about the threadserts (not helicoils) that are now being sold and used (It's a little sheet metal thingie, formed for both right and left hand threads), the trick is to use an old pedal spindle to set the threadsert into the arm with red Loctite to hold it in place. Once the Loctite has had a chance to set up, file or grind off any excess on the back, and then remove the dummy pedal spindle.
I think you can still get RH threaded spark plug helicoils in the correct size and threading for this, but as far as I know, nobody is making and selling the LH ones any more. Just the threadserts.
Well once again I find my memory a tad faulty. My comment about the last thread and the arm face was wrong and is about a drop out hanger repair Heli-coil, the few threads involved adds to the problem there. (And since have used T nuts a few times).
Back to crankarms and my now corrected memory. Here's a shot of the kit I used. You are correct in the method of setting the insert in place, I don't remember which LockTite I used but that aspect wasn't the challenge. As I replied to Dan's post for my personal cranks I used a drill press as a fixture and pilot for the reamer and tap. I have a vague memory of doing one repair freehand in a shop and thinking about how to align the insert. I will stand by my comment about this rethreading being the plan B. Thanks for the check and balance. Andy