[tyingq]

I suspect there's no free lunch here. If they are designed for hobby r/c aircraft, they are designed for shorter runs with lots of free prop-driven fan cooling. Not for sustained runs without a prop cooling it.

So, it would likely work, but have a shorter lifetime. The barrier to using them was having a low voltage / high current controller. This fills that gap.

So, not a bad idea, but there's almost surely a durability tradeoff. And maybe that's fine for a hobbyist cnc application.

[TaylorAlexander]

Cooling can be an issue if you drive them near their rated power without adequate cooling. And absolutely they won't have the same quality of construction as true industrial devices. However they are sufficiently powerful to be useful and cost effective at continuous duty levels below their max rated power.

[madcowswe]

One thing to keep in mind is that for many robotics applications, the duty cycle for high torque (i.e. acceleration) is often quite low. So they may still run fairly cool.