Actually it's REMOVE a faucet...Pfister, kitchen sink, and it used a metal nut on the central shaft that WELDED itself together and would not come loose! I worked on it for 3 days (Friday the 13TH! through Sunday), and when Pennywise was able to come on Monday their conventional efforts failed also - BUT - they did not give up...final decision was to saws all it off from the top of the sink WITH MY BLESSING. NO damage to anything but the faucet. Brought the whole mess of an event to a very good close.
After 1 1/2 hours work, success, and at a very reasonable price. My hat's off to Pennywise and my recommendation is here.