Quote Originally Posted by TrickyCNC View Post
I presume the weight of the gantry and Z and spindle will have a greater effect on the motors when used this way up ?

If you were pushing the motors to the limit when horizontal, then surely they would stall when up on end ?
I think the short answer is "it all depends". clearly the ideal(ish) option is for the gantry to traverse horizontally in X so the Y is vertical and only the cutting head/Z-axis has to be lifted against gravity, but then you lose the benefit of having the chips fall into clear space. Unless your X-rails are space out from the bed in some way.

Of course, you shouldnt be running near the stall point anyway, there's a high chance you'll lose steps on fast direction changes if you do...