I'd use one of these guys, an insulated one. Adjust one side by pinching with pliers to fit snug and push it onto the pin you want. Crimp your wire from touch plate to the connector and you're ready to go. The pin is held HIGH, so when the plate is shorted to the tool, (ground), the active low input in Mach will see the signal. If you use it on metal, the back of the plate needs to be insulated.
You then have to set it up in Ports n Pins and put a button on screen with Bretts little macro ditty.
RC

I just noticed......Kramer ?  And the Dallas Cheerleaders ?  I'm a big fan of both.