it seems proto changed the screw type/size for attaching coupler boxes. my older units had a common metric thread it seems, but my last gp7 from the 2009 run [#47854] has a different thread, almost looks like a self-tapper, and will not interchange with older units. any idea’s on this?
Unless, I’m mistaken, Proto coupler mounting screws were a Phillips flathead screw. I would just retap the hole to take a 2-56 flathead.