Atlas 618 Backgear Issue

[JRT]

I can measure mine- give me a few, I'll be back
OK the width looks like 0.20 inch and the OD is 1.125 inch
The diameter of the spindle there and for the cone pulley is 0.787 inch
then it narrows down at the left hand end for the bearing at 0.750 inch

Thank you for this. I the one I bought on ebay is too big in width (I think it may be) but fits the shaft, i'l just turn it down.