Quote Originally Posted by george uk View Post
The gantry i have planned will be below 40kg, fully loaded, probably closer to 35kg, I know how i will do the gantry, but have not finalised the design, as i need to think about what i might need to strap on to it.

I want to incorporate a turret on the end of the table, and a rotary table or b/c head on the table. and a geared 4th axis
Think you'll find your miles away with weight and to be affective and sturdy enough for cutting stone you'll be least in the 60-70's.
Like you say Speed isn't important but rigidity is massively important for cutting stone or any hard material with accuracy. To surface and cut stone effectively you'll need a slow spinning spindle with high torque, this alone will mean heavy spindle motor which will require a substantial Z axis to attach it too which will be heavy enough.
Mass greatly helps with surface finish so don't be chasing weight.!! . .. Better to be Chubby and Slow than Slim and weak.!

I wasn't going to mention this has seems you'd already ordered them but seen has Silva has already commented I will Confirm what he's saying. The cheap round rails will not take the Water and fine Grit that comes from stone dust, Add to this the weight and high vibrations that cutting hard materials will put thru the frame and they will die in short order.!!

My advise is cancel the order and Buy Proper Liner bearing other wise your wasting your time if your wanting accuracy and to cut hard materials. If you can't Cancel then sell them before using so still new and buy the correct components for the Job.