[OlfCNC]

You should definitely check it out, it works great doesn't have issues that the others in it's price range have. It will out of the box control a rotary axis (not in development) and it already has smoothing settings that are adjustable and can be saved for different types of machining 3d vs 2.5d (no issues with g2/g3 moves no pausing on direction changes). You get very smooth reliable motion no jerky motion no issues with complex 3d files. It has a spindle encoder for rigid tapping, 2000 line look ahead, touch screen compatible just to name a few features that you might like.

If you really need more than 4axis you can get one of the higher end boards. Centroid even has true closed loop controllers. Check out the Oak or the Allin1dc the Acorn is just their entry level hardware.

The thing that made up my mind to with Centroid is the software as well as the support you get. It is professional grade that has worked out the growing pains already. They are also aggressively making the software and hardware better. There's been 3 updates this year and they are very close to releasing the expansion card as well as the Router version of CNC12.

Dan

NTL funny guy, no pausing on direction changes?! What the ... ? I thought it requires slowdown and accelerating up for any axis to change direction otherwise your stepper motor would loose step. The acorn does not do any deccelerations and accelerations on direction changes? That's bad.

Rotary axis is also not in development with mach3, mach4, uccnc, linuxcnc, all support rotary axes and they all support at least 6 axis not 4 only like the acorn and no need for expansion cards, they do it out of the box.