# Kerf and Step Length Calibration

**URL:** <https://forum.lightburnsoftware.com/t/kerf-and-step-length-calibration/109904>\
**Category:** Ruida controllers\
**Created:** [September 8, 2023, 6:17pm UTC](https://forum.lightburnsoftware.com/t/kerf-and-step-length-calibration/109904 "2023-09-08T18:17:52Z")\
**Posts on this page:** 1\
**Showing post:** 3

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**Author:** ![ednisley](https://forum.lightburnsoftware.com/user_avatar/forum.lightburnsoftware.com/ednisley/32/40455_2.png) [@ednisley](https://forum.lightburnsoftware.com/u/ednisley)\
**Post date:** [September 8, 2023, 6:52pm UTC](https://forum.lightburnsoftware.com/t/kerf-and-step-length-calibration/109904/3 "2023-09-08T18:52:29Z")

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> [@ViciMike](#):
>
> set my steps per mm to that value

Do this in two steps:

- Adjust the step/mm distance
- Measure the actual kerf

[Measure the distance moved](https://softsolder.com/2022/06/14/omtech-60-w-laser-axis-scale-check/) using an accurate scale. I used the red-dot pointer on a steel scale:

[![](https://softsolder.files.wordpress.com/2022/06/pxl_20220613_141505973-omtech-axis-cal-dot-positioning.jpg) ](https://softsolder.files.wordpress.com/2022/06/pxl_20220613_141505973-omtech-axis-cal-dot-positioning.jpg)

Lacking a pointer, you could measure the distance between two pulsed holes in paper or some such. The key concept is that the distance does not depend on actually cutting a shape; you can estimate the center of a dot or hole very accurately.

[A few iterations of the calibration routine](https://docs.lightburnsoftware.com/ConfiguringRuida.html#step-length-calibration) should get you very close to the right answer.

Once you have that for each axis, _never change it_. It is a property of the machine axis, not the lens or cut or power or anything else.

Then use a [kerf measurement tool](https://forum.lightburnsoftware.com/t/kerf-offset-test-with-built-in-vernier-scale-for-accuracy-no-tools-required/98333) to find the cut width in whatever material you’re using. Apply half that value as the kerf adjustment in the `Cut Editor` or `Offset` tool.

That should get you as close to perfect as you need to be.

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_[View the full topic](https://forum.lightburnsoftware.com/t/kerf-and-step-length-calibration/109904)._