Robert,What you describe is how I think the safety works. I thought a little about drilling and tapping the trigger to make the square nub higher but I think a longer allen screw in the safety shaft is a better idea. I often go to McMaster Carr for things like this. They don't tell you shipping when you place the order but they seem to charge what they paid.Jim
Robert,I don't remember how small they go to but the Home Depot's where I live have little jigs on the poles in the hardware section with what are bascially nuts you can turn a screw into to check the size. That might work too. I have a set of tap and dies which includes thread gauges so that is what I use - but I did not pull that screw entirely out. Jim