Originally Posted by
FBinNY
I agree that cleaning up dinged or nicked threads is useful, and use both triangular and thread files for all sorts of work.
BUT
It's not appropriate for a stripped thread, since the issue is that the peaks are too low to engage the mating part. Filing away more material won't raise the peaks, and so is useless in this application.
If the threads are shaved flat-that is a wrap-it is DONE-
But since OP screwed his headset off-he still has some threads-he just can't rethread it-because he has threads pushed into the grooves-
the file removes some material-but it also pushes some -a little-back into place-now badly bent threads-tend to "break off" their tips anyway-
If something actually has been screwed out-and it didn't "cut/shave" its way out-meaning with lots of metal shavings-it is frequently salvagable-but no point in hauling a $20 fork to a shop for a $25 repair
The "bring it to a shop" useless advice for a cheap part.
And anything involving an expensive tool-useless also-
Who other than a bike shop will have a special sort of die for rerolling threads-and msny of them-probably just have a thread cutting die
No way is ANY sort of machining just $5-pure BS to suggest that-can't stay in business charging that little-quality tool is over $100-