Originally Posted by
phoebeisis
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 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-
You and I agree that bringing it to a shop is going to be too expensive except for a collector fork.
Where we disagree is cutting vs forming. Often stripped threads are sort of half and half with the mating part (headset in this case) with the thread mashed rather than removed. (if it's actually shaved off it is toast). Filing doesn't flow metal it removes it, but using a steel headset cup as I described earlier
might flow enough back to make it workable, whereas cutting more away definitely won't. Since it's a no cost DIY deal, there's little to lose - except the time to scrounge a good condition steel cup.
I also proposed other DIY make do solutions.