Looking at the banebot drawing on page 26, I come up up with the following for the 1/4-20 mounting holes:
Dimension parallel to the shaft axis, center to center: 2.263"
Dimension perpendicular to the shaft axis, center to center: 1.378", centered on the shaft axis. (0.689 off center axis.
These dimensions are from the "incomplete" banebot CAD drawing. We have used them in the past, but I won't physically have in hand until tonight.
PM me if these are not the dimensions you are after. Hope this helps.
Anyone else out there that wants to chime in to verify or change, please do!