208OZ.IN stepper motor

[John S]

Balls screws ? trapezoid screws? or timing belt ? the more friction you have to overcome the more power you need.
personally I'd feel better with a larger motor, 3Nm sounds a lot better.

As regards graphs, they do give a lot of information IF and that's a big IF you KNOW that graph refers to that particular model of motor. I'm very sceptical on what gets released from China as regards what it applies to.

Like those test sheets issued with rotary tables and the like , everyone passes with the exact same results ?

[Robin Hewitt]

That would be an F1 Ferrari plasma cutter then? :naughty:

Let's make it work hard, 1" travel per stepper rev, massive 20kg gantry.

If I've got the maths right, 3Nm would do nought to 83 mph in one second.

I know you need some degree of overkill to compensate for the losses, but a smaller, faster revving motor would seem to be a better bet.

[JAZZCNC]

Like John S says more info required.!! All that John asked plus gantry weight or material/design plus type of linear bearings used.
Robins reasoning is sound enough but really without the full picture then can't be answered accurately.

Personaly I know of a 8x4 plasma that use's 3Nm motors geared 2:1 without any issue's but that use's R&P which hisn't the most efficient, also use's some crappy home made linear bearings.!!