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### Author Topic: Steps per Inch Calibration  (Read 2826 times)

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#### illica

• 5
##### Steps per Inch Calibration
« on: December 03, 2012, 11:36:01 AM »
Newbie here... following a Youtube I saw for setting Steps/In Axis Calibration, I went to my Settings Page. After setting up/zeroing my dial indicator, I clicked on "AXIS CALIBRATION-Set Steps per Unit" icon. I entered 1" (for X axis) and <Entr> I got a Dial Indicator reading of 0.219". I then entered that value upon request for the measured axis movement. MACH3 replied back with a calculated Steps/In of 8000+(appx). I accepted. When I reran this procedure I only got a movement reading of about 1/2 of the 0.219" What am I doing wrong? Any help would be appreciated.

• 4,876
##### Re: Steps per Inch Calibration
« Reply #1 on: December 03, 2012, 01:59:04 PM »
Using TURN ?

#### illica

• 5
##### Re: Steps per Inch Calibration
« Reply #2 on: December 03, 2012, 02:42:01 PM »
1st- THANKS for the reply. 2nd- I'm just using Mach3 with a simple X, Y, Z 3-axis CNC router. Not with a lathe (by your question 'Using TURN?', I interpreted it to mean  'am I using a CNC lathe?'). If I misinterpreted your question, I apologize... Thanks again.

#### illica

• 5
##### Re: Steps per Inch Calibration
« Reply #3 on: December 03, 2012, 03:33:44 PM »
Here is more info... my Axis has a stepping motor that turns 1.8deg/step. I calculate from this that a full 360deg should take 200 steps. The lead screw for all axis' on my CNC have 4 tpi. Am I correct in calculating that it should take 800 steps to move one of the axis 1"?

#### Hood

• 25,855
• Carnoustie, Scotland
##### Re: Steps per Inch Calibration
« Reply #4 on: December 03, 2012, 04:32:56 PM »
You also need to factor in the stepping  of the drive and any gearing. From your first post I suspect  you have a 10 microstep drive with no gearing between motor and screw and thus your steps per inch would be 8000.
Hood

#### illica

• 5
##### Re: Steps per Inch Calibration
« Reply #5 on: December 03, 2012, 04:42:18 PM »
Thanks, Hood... will try tomorrow and report back. I appreciate the help.
Joe (in NC)

#### illica

• 5
##### Re: Steps per Inch Calibration
« Reply #6 on: December 03, 2012, 06:04:49 PM »
Hood. I plugged in 8000 and was getting about 2" of travel. I reset all 3 axis to 4000 and it was real close to an inch. I tweeked the values, using my dial gage and the settings page Axis Cal procedure. THANKS for everyone's replies... Big help. This is a great site and this was my 1st posts.

#### Hood

• 25,855
• Carnoustie, Scotland
##### Re: Steps per Inch Calibration
« Reply #7 on: December 03, 2012, 06:14:36 PM »
Something not adding up quite right there but suppose if its working then thats all that matter.
For my curiosity could you say what drives you are using and if you have gearing between motor and screw.
Hood

• 4,876
##### Re: Steps per Inch Calibration
« Reply #8 on: December 03, 2012, 06:20:36 PM »
Just curious .... what's up with the Axis Calibration ? ? ? Micro-stepping, gearing or not ....
It's usually much closer than 50% off.
(Ciferin' it is my preference also)