I used 1/2 inch carriage bolts to mount mine.
By Ferdinand Evelina
I believe they are 1/2 inch but I used 3/8 bolts because of the length required tp mount to my work bench. This is a well made vice with many uses. I use it all the time.
By Rex Hamlet
Clearance for a 12mm bolt. Or .465
By Keith Ella
4 bolts hold the vice.
5 inches between each center bolt.
By Clark Edmund