what type of stainless steel? I have a piece of SS and don't know what type it is how can I find out?

You can test it with a magnet. If the magnet doesn't stick then its.....non-magnetic :D This would likely mean a 304 to 316 grade. You can heat up a piece (red hot) and quench it, and it will not test any harder than it was before.

If you cut a sample in a lathe, and it forms short chips, it is likely a sulferized grade, like a 416 MX. This grade will also harden to some degree (40 Rockwell), which may not seem all that hard (nowhere near "file hard") but they call it hardenable.

The other types that are used for hardened blades and stuff, I don't know about. They would be much harder, I guess, if you heat up a piece and water quench it to find out.

find someone with an electron microscope and it will print out what elements are in it and how much of each one. then compare it to a stainless alloys chart. Metalugical lab a good place to start.