Originally Posted by
merziac

See post #19-24, we discussed this at length and yes they can save the day with patience and practice.
Yes, thank you, mea culpa! The one I have is the same as the one in your picture.
I used it very extensively on wheel axles, hub cones, BB cups, and freewheel threadings when rebuilding my friend's two Witcombs. Used carefully, it's a great way to "subtract" the distorted metal which prevents threads from interleaving. When the damage was done the possibility of a full strength joint was reduced, but with the ability to join restored, a lot of bikes can be good enough.