Thank you for your inquiry. That nut threads are 1/2".
They're only designed for Kreg's Universal and Multi-Purpose steel stands; they have not been tested for anything else.
3 inches, I installed on a Home Depot work bench. The total is 5 inches which is a little high. I like Kreg products reason for purchasing.
The stems are approx. 2" long.
Thank you for your inquiry. The bolt diameter is 1/2".
Each caster has a load capacity of 150 pounds.
They are ½". Don't know the thread pitch, but the nuts are included. FYI, these are supplied to Home Depot by Kreg.
I would say they are too large for a chair.