Well, contrary to my claim that I could let it go until the next rebuild, I am going ahead with fixing the helicoils. Still seems like plenty of winter left to go, here in Chicagoland.
When I screwed these up (no pun intended), I was definitely rushing, so as not to impose too much on my friend with the drill press. So, in order to do the fix, I finally broke down and bought my own; a cheap but, I think, nice little bench-top model. What the hell was I waiting for?
The one-by-one approach is pretty basic: remove the bad helicoil; redrill the hole perpendicular; re-tap the hole with the tap in the drill press, turning the chuck by hand; install new helicoil with plenty of blue Loctite while holding as close to perpendicular as possible.
When doing the test run for this method, I learned a couple of interesting (to me, at least) things about helicoils. First, I had to be sure the bottom turn of wire just beyond where the tang breaks was supported by thread and not occuring where the angled hole ran away from the coil, otherwise, the coil can distort when breaking off the tang. Second, not critical to the fix, but I found that when removing an existing helicoil by using an awl on the top thread, the wire bends inward in a way that basically forms a tang on top, allowing me to use the coil inserter as a remover. By grinding a knick beyond this new tang, the coil can be reused. I'm not reusing them, but could if I had to.
Enough with the blather, here are the photos. It's pretty embarrasing how bad the original job was, but I'm pretty happy with the fix.
Richard L.
