[TheForge] post vise repair

[Cindy and James]

A bit off the topic of forging a post vise... I've got several post 
vises that I would like to use but the threads slip, which is likely the 
most common problem.

What is the best and the easiest way to repair these?  I know that the 
answer to "best and easy" may be completely different.

I have considered simply taking the thing apart, cutting the handle off 
and welding a new acme thread shaft onto it, and welding a compatible 
nut inside.

Has anybody done this successfully?  Is this a REASONABLE solution?

I have talked to some hobby machinists about making new nuts or shafts 
to match what is there and they all shy away.

JA