What size vise is this?

[Wamsutta]

Mower Medic 1 video. He's getting ready to press some bearings into a string trimmer fan housing.

How big is that vise? Are vises sized by jaw width?

 

[The Cobbler]

I'd say 4 or 5"
they are measured by jaw width, which to me doesn't seem to make sense

 

[Wamsutta]

I'd say 4 or 5"
they are measured by jaw width, which to me doesn't seem to make sense

You would think they'd be measured by capacity like a bar clamp.

 

[General Geoff]

The most typical bench vise size measurement is by jaw width, but that's kind of like defining trucks by wheelbase and nothing else. So many other factors like throat depth, opening capacity, overall mass, material, tensile strength, main screw thread pitch, maximum clamping force, etc.

The Wilton in the OP photo, looks to me like an older 400S