One BF20L more

[antomost]

i am not an expert on the subject. My thought is that because of the z axi's weight, extra power may required. Also the ballscrew is M20 instead of M16 used on the X-Y axis

[AndyUK]

i am not an expert on the subject. My thought is that because of the z axi's weight, extra power may required. Also the ballscrew is M20 instead of M16 used on the X-Y axis

Ah! Were those sizes of motors recommended by another build then? There is a motor size calculator floating around these forums somewhere, although I don't know if it also calculates for servos - you might find it interesting.

My line of thought was that the Z axis is typically held in place moving less frequently with lower accelerations, whilst the X and Y have to deal with the cutting forces - hence why I asked the original question. I can certainly see your logic - and the inertia of the larger screw will make a reasonable difference.