Re: Recomendations

Hello,

One thing to consider with any rack pinion drive is pressure angle
(pa). 14-1/2 degrees used to be the standard, but it has all but been
replaced in modern applications with 20 degrees, which is stronger.
HOWEVER, the 14-1/2 is better for a linear drive, as there is less
force trying to "push apart" the pinion and rack. Also, "center
distance" variations will result in less backlash with 14-1/2 vs. 20
degree pa's.

Hope this helps.

Ballendo

P.S. For us to help with the other questions, we need to know
the "required speed", and any other "drive" decisions already made
(voltage of ps, size planned for motors, driver type/model, etc.)

P.P.S. Shopbot has a lot of info on their machine at their website:

http://www.shopbottools.com Since it is a rack/pinion drive, it may
be some help. You can get everything from pinion size to motor
gearing.

--- In CAD_CAM_EDM_DRO@y..., "tonyrice66" <tonyrice66@y...> wrote:
> Hi, everyone.. been lurking here a while.
>
> I,ve got my table & gantry built for a cnc plasma cutter, but I'm
> wondering what pitch rack & pinion I need to get the required speed.
>
> I need help on stepper motor size & what control to use, any help
> would be appreciated.