DIY Build of Aluminium CNC Wood Router without Workshop & Tools

[irving2008]

If your drill is sharp enough you need relatively little torque to drill, much of the time the spindle will do most of it under its own weight...

Its all to do with cutting speed, feed rates and chip sizes...

Basically to drill a 6mm dia hole in Ali, needs a drill speed of 5000rpm and a feed rate of about 10mm/min (all nominal values, taken from one of the many online feed/speed calculators)

The force needed to push the drill through the material is roughly 6N, and the cutting power about 10W. (yes its theoretical, Jazz)

That 6N of force needs 5mN of torque on a 5mm screw or 10mN on a 10mm screw... it generally makes little difference so other parameters, such as cost, apply...

Though these are theoretical numbers, even if they are an order of magnitude out from reality, it still makes no difference. The main job of the ballscrew in the Z axis is to support the weight of the spindle, not to make a vertical cut...