Looks good as a servo mount. Thanks, admin.
But I actually needed to mount it to a hub for a 6mm flatted shaft from a gearmotor. Here's how I ended up doing it. The Lynxmotion hub had a #4-40 threaded hole at the center and a #4-40 screw for bolting it on through the center of the wheel. The problem is that the wheel hole size is a #8, not a #4. Tssk, tssk. Very sloppy, Lynxmotion. So I bored and threaded the hub for #8-32. The wheel fit very tightly on the #8-32 screw and was nicely centered. I used a star washer on the outside and some threadlock to make sure the screw didn't back out. Bootiful.