shocking me,touching metal?

When you say a single wire 220v and neutral, there is no ground. The saw came from the US with a three wire plug. That third round pin is ground. Without that, there is no path from ground currents to return, so they are sitting there at a potential until you grab it and shock and potentially injure or kill yourself. Can you add an earth ground to the transformer? Its pretty dangerous without it.

Questions:

transformer primary. 3 wires, or two? Hot, neutral; or Hot, neutral, ground?

If two wires, is the plug "polarized"? If so, one wire might be acting as ground. This should be connected to metal box enclosing the transformer. You want the metal case of each device connected to ground.

Skill saw: 3 pin, or 2? If two, is it "double-insulated" and polarized? It should be.

If the saw has a metal case, it should be 3 pin, and the ground pin should be connected to the case, inside the saw. Furthermore, you'll need to connect the ground pin to the case of the transformer, which should then be connected to building ground.

I'm going to guess that your transformer secondary ground socket is not properly connected to ground on the primary, and that it is just "floating".

I disclaim any liability for my comments.