# Thread: How to calculae Steps Per

1. ## How to calculae Steps Per

Trying to tune the motors and having a hard time getting the steps per figured out. I have 5 mm pitch ball screws and 200 step per rev motors (1.8 deg)

To my calculations that should be 10160 for the steps per but it is not quite right. I used the set steps per function in MACh and it comes up with 9948 which is not quite right either (I am measuring as close as I had available - dial caliper old). I need to set up a dti but still would like to understand the math.

Any help.

2. Just for clarification - it seems that you may be using a Gecko G540 driver with a 10 microstep setting, and you are looking at calculating steps per inch? If so, my math comes out the same as yours.

If you work backwards from 9948, you come up with a pitch of 4.974 mm.

So I'm wondering just how close to 5 mm the pitch actually is. Could you measure that (or have you measured that) by counting off a larger number of full revolutions and using the calipers to get the linear movement of the nut, then dividing by the number of revolutions to get a more precise approximation of the actual pitch?

3. ## Close

Gecko 203 - still a 10 microstep controller.

I look for possible sources of backlash and get an indicator setup to see what is really what.

Dan

4. I used the 'calculate Steps per unit" button on my mach3 settings screen.

you enter the distance yo wish to move, mach does the move and asks how far the move infact was.

Start off with a VERY small number! Then work up for a higher accuracy

If you asked for a move near the limit of travel of the axis....and the default settings are out by 2000.......Oooops!

Liam

5. ## Got it figured out

My first intuition was right. 10160 is correct. I was getting quite a bit of backlash for various reasons in both the x and Y. When checking the move in the same direction, thus removing the backlash, the numbers came out right using the set steps per inch. All verified with a Dial indicator. I am within .002" in an inch and will fine tune from there as time allows. That may be the lead error of the screw as well.

As I get time I will try to dial it in more.

Dan

6. ## similar issues

i just showed up to make a similar post. i'm running a new gecko g540 and i downloaded the .xml file from geckodrives. the motors run super smooth at 20000 steps per inch but my actual travel distance was incorrect. i was able to calibrate all axis accurately cutting my steps per nearly in half , and now my motors do not run smoothly.

UPDATE: it suddenly crossed my mind to round to the thousandths place, nice and smooth.

1. ###### Thread STEPS PER DEGREE | CNCzone.com-The Ultimate Machinist Community | BoardReader
04-16-2012, 07:25 AM