In need of sprockets

Does anyone know where to find sprockets for the taigen (van door) motor?

We bought sprockets made for a three eights (3/8") shaft and drilled them out to 11mm or so and then screwed them onto the shaft.

where? or has them as for the drill bit i just got a metric caliper measure the shaft to be about 11mm or so and them found a drill bit that was close to 11mm


PM if you need more help with the sprocket