Craftsman 508-51800 vs 508-51801

A while ago I got this poor vise (508-51800). I felt sorry for it and took it to try fixing it. Well, the vise nut was stripped (took me a while to take it apart as it rusted solid) and one of the jaw insert screws/holes is stripped as well.

I am periodically looking for a very cheap replacement vise nut, but had no luck at this point (no rush to restore - I know, you can find those vises for relatively little money in great shape. I have another 4 vises to use...)

Does anybody know if the parts are interchangeable with 508-51801? (or any other vise for that sake). For some reason I saw those for parts several times since I started looking...

...I just keep it in the basement for now: it I will find a cheap parts vise, I will try to learn how to rethread a jaw hole fot insert nut with a tap for a new nut and restore the vise (will be a good learning opportunity as I never restored the vise in my life...)

The 51800 is the older version. The 518001 has only minor changes but the slide dimensions are the same. Picture shows old slide in new body so the nut is the same and will work.
The next picture is the 51800 slide in a Columbian D43 1/2, so that nut will work as well. I assume you know that Columbian made that style Craftsman vise for Sears.
The jaw screw is a 1/4" 20 thread flat head machine screw. The standard taper is to long to fit and will have to be modified most likely.
Good Luck on your project !!

Thank you, Getridaone. This helps a lot!
Now my part options increased by a lot!!!
I previously found a code list for Craftsman and even tried to contact Colombian just to learn that Wilton took over...

Do you know which size bolts were used for jaw inserts?
Which tap and what bolts should I use for retread and replacement of the bolt?

As I said above it is a 1/4" 20 thread screw and the same size tap would be used to clean up the threads.If the missing screw is broken off in the jaw you will have to drill it out. Start with a small drill bit and work your way up to just the inside edge of the threads. Put the tap in and the remaining thread should come out in pieces.
The head on a standard screw is larger than the one in the vise. You might possibly find some to fit if you get lucky. The head will have to ground down to fit in jaw.

Hmm I have a Columbian main screw nut somewhere.....

Thank you, Getridaone! Sorry - misread your first message reading from cell phone.
Just had a small progress on the vise: I decided to see if I can save the screw hole. I thought that the smooth walls of the hole might be due to the screw thread rusting through and sticking inside. I took a bottoming tap (1/4 x 20) and tried to rethread the hole over the smooth wall rust. After some small passess and cleaning tap and hole from rust I got a a new thread. Well - may be it is slightly shallower, but when I tried the screw from the opposite side of the jaw, it went in well and held pretty well (did not put too much force, but it was holding the insert well)
THANK YOU!!!

Bluebolt, please let me know if you find the nut (I will PM you as well)

Nice find, thanks for Saving It. Good luck with the resto!
Kind of like an animal shelter rescue of a dog with a broken leg. ........LMA0