Old post vise thread repair

[Gotcha640]

My dad does some blacksmithing at the nature center near our house, think Colonial Williamsburg on a small scale.

One of the tools he's just got is an old post vise. It looks period correct, and it's a lot better than the bench vise in the shop, but the threads are pretty badly worn. Must have been used dry for years.

He was talking about restoring it a bit, and I found a YouTube of a guy doing a pretty thorough job, but he didn't do much to the threads.

For the male section, I was thinking about getting measurements and adding some material to the threads, then turning back on a lathe. Not sure how easy it would be to end up with something that fit, but max old iron.

Other choice would be scaffold leg. I could sandblast the zinc off and phosphate it to look old, but it wouldn't be vintage.

Any other ideas?

 

[zkling]

Do you have any picture or dimensions to share? The box or nut/female portion of the threads is going to be the challenging part. The early ones were just a steel spiral brazed or cast in place, the later were machined.

They typically use low pitch square, trapezoidal or acme threads which require a pretty substantial lathe to cut the low pitch on.

You could go hydraulic, but it certainly won't be "period correct".

 

[Farmer J.]

I did hear of someone who built up the worn male threads by putting beads of weld along the top of what was left of them, then cleaned them up with an angle grinder whilst rolling the thread along the ground under his foot... Apparently it worked 'ok' afterwards, and was a lot smoother after he slopped a handful of black grease on the threads.

 

[Gotcha640]

I'll get pics later, just thinking about it in the middle of some company training.

The problem with the weld and clean is I assume it would be rougher on the female side. Female on this one is about 5 inches and is part of the alignment with the other jaw.

As for form and function, when the place is open to the public on a nice day, he might do 3.5 hours talking and 30 minutes actual forging. Looking the part is more important. When he's out on a rainy or closed day, he might do 6 hours solid.