Bracket/mount riser for 55/57mm CNC motor

This is a riser for the aluminum mount that comes with many 300/400/500 watt CNC motors. The stock mount clamps on the narrow body of the motor, which reduces the available z-axis travel by about 15mm. (This is particularly important on a 3018, which only has about 40-50mm of total travel.) Using two of this riser (as I'll show in picture), you can get that back without cutting any aluminum. I recommend printing these in ABS at 100% infill, so there is no concern about crushing under the heat and force of the motor.

I'm using this with the upgraded z-axis mount that Corentintav designed: https://www.thingiverse.com/thing:4091764 (I highly recommend -- it works well.) This needs four M6x100 bolts, rather than the M6x70 ones he specified. (M6x90 might be long enough, but the 100mm length doesn't interfere with anything.) I've also included files for printing M6x100 bolts, a derivative of https://www.thingiverse.com/thing:193647. (With Covid-19, Amazon is taking forever to ship.) If yo