Hey Bill, hey all,
…for inspiration: The lower part of X gantry and lower part of Z slider in motion (Youtube)
Suhner milling motor
(motor is a Suhner UAD 30-RF, a 1050 W 3,500-30,000 RPM milling motor made exclusively for cnc-step by Suhner. It is an improved version of UAD 25-RF (Suhner Catalog) (Made in Germany). As you can see below, it has double bearing and the motor flange is all-steel. It is explicitly said to be able to mill 6 mm steel in the medium speed range around approximately 15,000 rpm and it is said to be relatively quiet (despite being no spindle but a universal motor with carbon-brush commutators) with 72 dB at 9,000 rpm. It takes collets for bits up to 10 mm and 3/8″ and there is even a tool changer (with ISO 7388-1 SK15 machine taper) available.
@ben, yes!!