Be careful what you buy.
Probably 20+ years ago before the advent of the big box stores and harbor freight I picked up an inexpensive 6 inch vise, heavy cast steel, all the pivots, small anvil on the back, it has been everything I ever needed, worked flawlessly for 20 something years, well I was recently building a minibike frame for a grandkid, I would heat the tube ends where the axles go, and where the all of the joints come together,( its a take off on the old Taco's), and crush them flat in the vise, hammer a bit on the anvil, heat, crush repeat, well the gear portion of the jaw couldnt take the abuse, one of the teeth stretched, now the vise wont hold, so my moral is dont buy cast, get machined steel, you will be able to give it to your grandkids.
I am looking for a nice old machinests vise now in garage sales and swap meets