Re: Motor Size estimate?

batwings@... wrote:
<snip>

> I'm using Techno-ISEL screws and they're kind enough to give a force formula:
>
> M=F*p/2000*pi*E
>
> M is torque, N/m, F is force, Newtons, p is pitch, mm, E is efficiency.
> They give an example with 10mm pitch screw and E=90%: 50 oz-in direct-drive
> produces 45 lbs thrust. That would be 90 lbs at same torque and 5mm pitch,
> 450 lbs at 5:1 and slightly over two short tons at 450 oz inches and 5:1.
> No wonder it pushed over! That be enough for you?

Hoyt, do you have this formula copied correctly, as it seems to imply
that an increase in efficiency would require MORE motor torque. I would
have expected the reverse.

I am presently designing & building a desktop CNC mill and need to know
how much I can push with my motors.

Cheers.... Andy