That is the way Hunter employees did it and I'm sure so did L.C. Smith Maker employees did, but that is what they did day in and day out. Like I said one slip and you marred metal and wood. In Brophy's and John's book it shows Hunter employee doing such job. They used a nail set/punch with a 3/32 shank inserted into the top lever shaft and with a screw driver that had a "V" notch in it to push the punch/top lever into it's fit. Also you have to be careful in how much tension you put on the trigger plate housing screws as you will push the top lever shaft away from it's fit. Then you have to reach below and tap on the lever with a rubber mallet to make it fit. No thanks, once was enough,I prefer the c clamp.