Bench vise

[RAYMOND SKRABANEK]

I have an American vise 5" that has a broken 3/4" spindle nut. It is not repairable again.
I am looking for a steel 10 thread square nut that is 2 inches long

[David Buchhauser]

You might try Roton for 3/4"-10 Acme nuts. You may need to purchase several and join them together (weld) and modify the hex shape to fit your needs.
David

https://www.roton.com/family/acme-right-screws-and-nuts-7060206/ (https://www.roton.com/family/acme-right-screws-and-nuts-7060206/)

[Tom Bender]

You might be ready for a new vise, but have a look at McMaster Carr. They sell generic stuff.