Machsupport Forum

Mach Discussion => General Mach Discussion => Topic started by: kauaicuda on September 05, 2011, 11:08:15 PM

Title: Something HAS to be wrong with my steps per inch....
Post by: kauaicuda on September 05, 2011, 11:08:15 PM

Hi folks.

Im a total newbie, I'll admit.

Im running a cncrouterparts.com design 80/20 build.

I'm using a Gecko G540, Nema 23 steppers, 5 start 10 tpi leadscews, and of course mach3.

I have seen others using steps per inch at "4000"

200 step motors x 10 microstep drives, x 2 turns per inch on the screws.


But, my steps per is only accurate around "160". Thats right, one-hundred-sixty.

And thats a rough estimate, I havent measured it with any accuracy,

I cant figure out what I'm doing wrong. Any ideas?

Title: Re: Something HAS to be wrong with my steps per inch....
Post by: HimyKabibble on September 06, 2011, 12:29:16 AM

You're probably running in metric, rather than inch, mode....

Title: Re: Something HAS to be wrong with my steps per inch....
Post by: kauaicuda on September 06, 2011, 07:41:57 PM

Yep.   Sure was.

Here's where it gets really interesting.

I reset my steps per inch with mach loaded up with no G code.   

I had to set it to about 100,000 steps per inch to be in the ballpark of 1 inch.  I knew this wasnt right, but it worked....sort of....The DRO on mach read 1 inch of movement for 1 inch of travel.

Then I loaded my G code, and the steps per inch was no longer accurate.   It changed, with my G code loaded, to where I wanted to be, 4000 steps per inch.

Great, I suppose, but why did my "steps per"   change when the G code loaded?