Welding is a good option if you can do it reliably. Weld a nut on it, or even the end of a rod and grab that with the vice grips, or often I'll just weld a little pile on the head, grab that with the vice grips. And if it is a rust problem the heat of the weld is quite helpful.

Grigg

•1951 GMC 250 in the Project Journals
•1948 Chevrolet 6400 - Detroit Diesel 4-53T - Roadranger 10 speed overdrive - 4 wheel disc brakes
•1952 Chevrolet 3800 pickup
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"First, get a clear notion of what you desire to accomplish, and then in all probability you will succeed in doing it..." -Henry Maudslay-