8x4 router build. Steel base & Aluminium gantry gantry

[JAZZCNC]

Best advice with regard to Z axis is to put rails on front plate, bit where the spindle mounts, and bearing blocks on back plate, i.e. opposite to what you've shown.

Normally Eddy I'd 100% agree with you but with such short travel then no I'd go with something like how it's set out now. Thou I would have the bearings on the front plate lower with next to no overhang and extend the spindle down in the clamps. This will give full support to spindle/front plate from the rear plate.
If longer travel then I'd set it out other way.

Derek I wouldn't mix servos and steppers and go with same on all axis. Not that they can't mix but it keeps electrics all the same and there won't be much difference in price. If your going with servo's or even steppers for that matter then suggest you get a decent motion control card. Definately will need one for servo's to get decent performance out of them.