About to build CNC miller, need design critique please

[m.marino]

Adding to some good points already given,

1) rotate your rails so that they are opposing each other (one facing up and one down) That will bring your Z plate closer to Y as well as be a better transfer of force when cutting. Boxed section to mount them on with index plates to insure alignment would also help. Given the limit on space you might look at different options how you are mounting the X axis motor as that is costing you 60 or more mm off Y movement and if you plan on using precision profile rail that means you will be needing around 200mm width of the z plate to mount them. Also making a "C" with box section and plate for the axis as suggested above will add a good bit to the rigidity you will need to cut steel. Good luck and will keep an eye out and let others add their much greater depth of knowledge to this.

Michael