Hardtail PSI?

What is the ultimate PSI strength of the base metal in the hardtail vise? 70ksi?

Guess no one wants to advertise this info.

Can I ask why this information is important?

Weakest link thing… Don’t want to spend money (mount/stand) on material that is weaker or a lot more stronger than the vise itself. Somewhere near it would suffice…maybe just below for the sacrifice prior to hurting the vise but want to get most limit as possible without spending more than I need.

Do you have a 614 Hardtail?

Didn’t know there was a model number… Have the 6.5" jaw…14" opening. Didn’t know there was a 5" version…don’t think it was available at the time.

Nice, you’ll be fine with a 1/2 or thicker mounting plate. Here’s a link to a video of live vise base testing.
Giant Hammer Impact Testing the Fireball Hardtail Vise to Failure - Part 2

Size doesn’t dictate yield or ultimate. Plan this vise to be a third hand hold for front clips with engine/ trans suspended.

True, but it’s not like there’s a huge difference between 70ksi and 80 or 60ksi tensile strength. You still want to overdesign it a bit. If the man says 1/2"+ is strong enough, go with 1/2"+.

Obviously I’ll have to go with what he said as it’s obvious this is some “trade” secret. I personally would not want that liability…saying 1/2" is good not knowing the details of the application. Typical cast steel is 36ksi/36000.

The vise is cast ductile iron as far as I’m aware. The minimum tensile is around 60-70ksi on average, which is about the same as 1018 steel.

That makes sense…it’s cheaper. 40 is tensile…70 would be ultimate. CS max is 36…just don’t break it.