You will need to broach the gear with a 2mm A broach using an arbor press, and use a vertical mill with a 2mm end mill to mill the keyway into the shaft. Alternately, you use a 3/32 A broach and 3/32 mill, but have spare parts made for insurance. I usually mill the keyway a little deeper than 2mm to account for the chordal distance across the shaft. In addition, when you order keyway stock, get unplated steel stock as plated stock is a little tight and will require some sanding or filing for a proper fit.
