A few years ago I had several re-constructive surgeries on my arms.
After each surgery they made a custom brace out of plastic that is
heated in water and formed around the offending limb. After the
swelling went down all I had to do was hold the brace above a steaming
tea kettle to soften the plastic enough to re-form the brace to a snug
fit. I saved all the braces. Then, last week, I had a job that
required re-threading a brass screw with a fancy round head. The head
was .750 dia and had a sharp edge where the rounded top met the
bottom. It also had an "antique" finish on it. I bored out a slug of
aluminum in the lathe and then heated it until pieces of one of the
braces would melt. After pushing in enough plastic to fill the hole I
held the threads in a drill chuck in the tailstock and pushed the head
of the screw into the plastic. After it had cooled the screw was held
tight enough to center drill. After centerdrilling a live center was
used to hold the screw in the plastic and the threads re-cut. It
worked very well. Rio Grande carries plastic with a similar
description. And you can get it clay filled for extra strength. So if
a hard to fixture part comes along this solution may be better than
Cerrobend.
ERS