hi Schiada96
Depends what material and what size Vee and what shape punch and what way the wind blows.
What I'm basically saying is that you can get a rough size from calcs which are normally good enough. but if you want it spot on test with a piece of the sheet you're goning to use
Our favourite for sheet - i.e, 3mm & less inside dims added up - works for us on mild steel in 8x mt Vee |