I bought a couple of sets of Bar stools. The frame is made of Metal. A couple of them spin really freely. I would like to tighten up the spin-ness of them. Any suggestions?

Depends on what type of base they are. On some you can simply tighten them and they will not spin as freely. If you can see the bearings you could also use a heavy grease on them. It will create drag slowing them down.