I was working nearby today when I realised that my earlier attempts at domestication had worn away. This had resulted in unnecessary noise due to the large clearance between the impulse roller and the impulse ramp jutting from the pendulum rod.
Loosening the 1/4" BSW [Whitworth] nut allowed me to easily adjust the stop screw with my fingers to set the roller clearance from the dead face of the pallet. It is essential that the roller does not run continuously on the underside of the pallet. A thin spacer between the lowered roller and the curved pallet may help where there is doubt regarding screw adjustment. The lock nut can then then pinched lightly to lock the adjustment screw in place.
No doubt a suitable strip of thin card, dropped on edge into the magnetic gap would do just as well in place of sticky tape. It might even save some wear on the original screws holding the front armature bearing in place.