# Weird Steps/mm Calibration **URL:** \ **Category:** Troubleshooting\ **Created:** [May 2, 2016, 9:46am UTC](https://community.inventables.com/t/weird-steps-mm-calibration/23200 "2016-05-02T09:46:19Z")\ **Posts on this page:** 3\ **Page:** 1
**Author:** ![Woody](https://avatars.discourse-cdn.com/v4/letter/w/ac91a4/32.png) [@Woody](https://community.inventables.com/u/Woody)\ **Post date:** [May 2, 2016, 9:46am UTC](https://community.inventables.com/t/weird-steps-mm-calibration/23200/1 "2016-05-02T09:46:20Z")
Just starting to setup GRBL 0.9J on my Arduino and am a little confused. The default setting for $100, $101 & $102 are all showing as 250.000 steps/mm, however when watching a calibration video on Youtube, the GRBL settings are showing as $100 = 40.000, $101 = 40.000 & $102 = 188.947 not sure why mine are so different. I am using Nema 23s for X, Y & Z. Hoping someone can explain the difference. Cheers … Dave ---
**Author:** ![LarryM](https://yyz1.discourse-cdn.com/flex009/user_avatar/community.inventables.com/larrym/32/51450_2.png) [@LarryM](https://community.inventables.com/u/LarryM)\ **Post date:** [May 2, 2016, 11:12am UTC](https://community.inventables.com/t/weird-steps-mm-calibration/23200/2 "2016-05-02T11:12:54Z")
Most likely the version of grbl that’s installed in your Arduino is not from the Inventables fork. Use this to re-flash the Arduino. > **[GitHub - inventables/grbl: Inventables X-Carve specific Grbl versions:](https://github.com/inventables/grbl)** > > Inventables X-Carve specific Grbl versions:. Contribute to inventables/grbl development by creating an account on GitHub. ---
**Author:** ![Woody](https://avatars.discourse-cdn.com/v4/letter/w/ac91a4/32.png) [@Woody](https://community.inventables.com/u/Woody)\ **Post date:** [May 3, 2016, 9:36am UTC](https://community.inventables.com/t/weird-steps-mm-calibration/23200/3 "2016-05-03T09:36:26Z")
Thanks Larry … thought there was a simple answer Cheers … Dave