“I bought a couple each of a few different speeds. I assumed the 1mm back shaft was geared, so I'd be able to use a normal small pinion - it's not. That shaft is attached to the motor core, not the gearbox.
I expect there is a use for it, but not for what I wanted. The problem with this sort of motor is that a 3mm keyed shaft is not an easy thing to use in a model. A plain 2mm or 2.3mm shaft would be much better for driving an existing gearbox, or coupling to a prop shaft.
I've seen nothing on the product pages, or in the reviews, to explain about the back shaft. For me, it's not useful and it's just in the way. I still have to find a way to drive anything with the awkward keyed 3mm shafts.”
“This is the third micro motor that I have bought for various applications, just as pleased with this one as I was with the previous two. I suspect I will be buying more in the future.”