No, I think the pin Casimer is referring to is the one in the trigger that holds the "mousetrap" hand spring in the older S&W's.
That's right. I'm rebuilding a j-frame trigger which has a hand spring that's been bent way out of shape ( don't know why ). So I purchased a new spring from Numrich.
This trigger has three pins, one of which serves as the hub of the hand spring. But unlike the larger 3 pin triggers I've seen, where each pin is of equal diameter, the j-frame trigger's hand spring pin is smaller than the others ( i.e. less than 1/16").
I haven't come across a punch smaller than 1/16". It looks like I'll need to improvise.