What is the difference betewwn the various Stanley chisel models? I picked up a 1" No. 720 at a yard sale for a buck without a handle and with some small pitting that I had to lap out. I have watched various discussions about 750s and Defiance models but I don't have a good understanding of which is which and don't know where 720s fit into the mix. Is there a resource somewhere that describes the different models?
Thanks in advance,
HB