Wilton vise question

[evanjames0178]

Wondering if anyone can tell me what type of screw goes in the centre of a vintage swivel base to mount it to the vise. Mine is missing. Base has a clearance hole in centre, vise has threaded hole. My guess is a shoulder bolt of specific length so it secures the vise, but still allows it to swivel when set screw is loosened. Attached is a picture of the screw I am missing.

 

[exmaxima1]

Yes, a shoulder bolt.

 

[RTM]

Or a regular bolt with a bushing to take a shoulder, since you may not be able to find the size you need.