Note：the drawing does not represent the real object, just show the parameters of the pinion

Object, M0.3 9T plastic pinion, two types, interference fit 0.8mm or 1.0mm shaft, thickness 4.0mm, outside gear diameter 3.3mm, weight 0.03g.

interference fit 0.8mm shaft of 6/7mm coreless motor

or interference fit 1.0mm shaft of  motor (right one below)

thickness 4mm

 Weight 0.03g, with 10pcs to test