[Veselin Kolev]

An idea on how to mount stuff to the big CIM shaft:

Get some one piece clamping shaft collars for an 8 mm shaft from mcmaster.
Get whatever gear or sprocket you want to stick onto the shaft, and line up their centers.
Cut two or three 0.125" pin holes through both of them on the mill, and insert pins with retaining compound.

Hence, you can easily make your own pinions with shaft collars on them, without having to buy expensive custom ones. Just an idea.