# Calibrating a rotary tool - How do you find the steps per rotation?

Firstly, can i just say how awesome lightburn is. RDworks is a nightmare for new users, lightburn is a dream <3, so much so i just purchased a license and a camera

I have a 900x600 Chinese laser with a Ruida RDC6442S-B controller and this is the stepper motor:

Can i check, are there tricks to working out the steps per rotation? the manufacturer doesnâ€™t know (or wont tell me).

thank you!

Nathan

and here is what the rotary tool looks like:

Iâ€™d start here:

Searching this forum for â€śruida rotaryâ€ť will produce more good results as well:

https://forum.lightburnsoftware.com/search?q=ruida%20rotary

ok, thanks Ray, Iâ€™ll give it a whirl on the weekend.

Hi Ray, so finally got around to sorting this out, and 100%, with a bit of guess work, i got there. Its good enough hey, i can make this work for what i need!

To the eye, it looks fineâ€¦ is there a mathematically way to calculate this?

In RDworks, there is a measurement vs. graph length setting, where i can enter the actual value of the cut / shape. Is there a setting somewhere like this in RD works, that re-calibrates the software to the cutting bed on the machine?

thank you sir for all your help, you guys rock my world

In LightBurn, youâ€™d go to Edit > Machine Settings and click on Calibrate Axis at the bottom, but this is only for the X / Y Z / U axis, not the rotary. We could likely do something similar for that though.

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The formula is as follows:
New Steps = Old Steps / measured length * intended length.

e.g.: You want to cut 100mm but get 105mm (meaning your current steps are too hight) and your current steps are 200:
New Steps = 200 / 105 * 100 = 190.476190

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Did this just for you my friend:

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One hour!?

okayâ€¦ going to watch the whole hour one of these days.

i could have summed it up and youâ€™d still have questions if youâ€™d prefer

not a complaint just a suprise

This video was very helpful and I had my rotary dialed in incredibly quick. Thanks so much!

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Question I have is when you change to a different diameter cup if you enter the diameter in lightburn do you still have to go through the process of finding the steps per rotation or once you know it for one size does it calculate it for you? I dont use lightburn but am interested in it and if it makes this process easier I may switch is why I ask.

Once you have that set for the rotary, you adjust the diameter of the object to be lased. You can try for yourself using our 30-day, Free Trial.

Hi, what if my steps were too low. What would be the formula to figure that out?

The same formula, just fill in the real measured values plus the actual steps as described.
New Steps = Old Steps / measured length * intended length