Perry S,

You're absolutely right. My brain's fried and I got my story wrong. What I should have said is the internal threads in the Asiatam output shafts were a large diameter, and require a larger internal socket head screw. THe head of larger Asiatam internal sockethead screw was larger than the counterbored hole in the sprocket. To give clearance for the larger screw head I used a 7.2 mm reamer to open it up.

Frank