I checked the math in the thread you referenced, and I'm not following exactly how they got to the numbers, but I get the same numbers. 500Hz step rate (100mm/s X/Y motor) is 125Hz to any one coil in a bipolar motor. 125Hz through 32mH gives the 25 ohms you quoted according to this calculator: http://www.electronics2000.co.uk/cal...calculator.php

For the extruder, 1350Hz step rate is 337Hz electrically through the coil. At 32mH, this is 68 ohms.

Still working on identifying the motor. It looks like other people have been asking Colin about them for a while, without apparent success. I'll see if I can get a direct measurement.