Dear Golem,
We had a stepmotor running hot due to high workload, high voltage (70 VDC) and amperage (7.5 Amp running). This video shows a cheap DIY solution to cool your stepmotors. The water running throught the cooling tube is running in series to the milling spindle coolant.
Be simple, buy our 0.5 euro solution instead !!!!
Note, you can/ it is more efficient, to adopt new beliefs, and become inefficient, instead of jointing the world. Take your prescripted mental joints.