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If, say, some fathanded individual had stripped a rack mounting point on an alloy fork and then inserted a helicoil to fix the problem and mount a rack - can the mounting bolt then be removed/refitted without upsetting the installed helicoil?
Thanks in advance.
If it’s been heli-coiled correctly then, yes, you can remove the rack attachment bolt.
Of course do you trust yourself the fathanded individual to have heli-coiled it correctly?
Hahaha indeed! I think I trust myself to helicoil it correctly - it looks a pretty straightforward job. I was just concerned about the strength, and usability, of the repair.
Maybe. Sorry. Helicoils are supposed to be permanent but in practice there's always a chance that it backs out with the bolt, rather than the bolt backing out of the helicoil. It's effectively a double sided thread, and if it's more attached to the bolt than it is to the hole, the wrong thread comes undone
It's not a disaster if it does, you can always fit another. (the kits are pretty inexpensive now, well worth having if you're a diy type)
Thanks @Northwind - that's what I thought might occur. I'm guessing a dab of Loctite might reduce the chances of this happening?
Might be better to drill and tap to the next size up than fit a helicoil? Probably need to drill out the rack for the bigger bolt too.
oddnumber
MemberThanks @Northwind – that’s what I thought might occur. I’m guessing a dab of Loctite might reduce the chances of this happening?
Yup, though I know some people recommend against it- not sure why. And a bit of coppaslip or similar on the bolt.
Don't drill/tap out to the next size.
The wall thickness of the original threaded insert may not be sufficient.
The helicoil insert is the best way forward.
If you break off the tang when its fully wound in then the 'spring' action of the wire insert will hold it tight against the tapped thread.
Thanks so much for the advice all, it's very much appreciated. @drnosh - if you break off the tang, won't it fall down into the fork leg?
Use thin nose pliers + dab of grease.
(I know, its easier to write than do it).
If the bolt that you are using is long enough to touch the tang, you are potentially disturbing the fit of the wire insert in its thread.
Thanks @drnosh - the bolt is M5 so the threaded hole doesn't offer a lot of space to get much in.
You want to fit a time-sert.
They are designed to have the bolt removed and replaced.
Our boat engine (Honda V6) stripped a spark plug thread a few years ago and I had a time-sert fitted.... No issues removing and replacing the plug.