Rotary Enabled - Alter steps on the fly?

Fixing to burn some circles on mugs.
Does the Rotary option being enabled alter the dimensions ?

I will be engraving the mug turned sideways, so top and btm of mug is in X axis.

To make the Circle not come out oval, should I squish the image 10% in the X axis, or just run it. ?

Once a wheel rotary is set up properly there is no need to change any of the settings.

A rotary is just a ‘round’ y axes.

During the setup you entered steps/rotation of the motor * the gear ratio. With the ‘wheel’ diameter it computes that the wheel moves the surface of the object the same as the y axes.

A chuck rotary will require the diameter to compute the surface speed.

If it’s set up correctly there should be no need to change the artwork. A circle on the y table should reproduce a circle on the rotary… that’s the whole idea…

Good luck


understood, saw a post mentioning that LB alters steps.

ok, So Lightburn doesn’t modify anything being sent, so measured X and Y are perfect.

Just curious about the optical illusions I have heard of circles being oval wrapped around mug.

That is configuration of the rotary.

If you have a tapered mug or some other not linear shape it will distort the image as much as it’s taper.

Good luck


ah, ok, so its not the curve of the mug that makes it oval, its the taper from top of mug to btm.

The idea of a rotary is to handle cylindrical type object. It runs the rotary same as the Y axes…

If a mug doesn’t have same size top and bottom then it is shorter at one end and that will cause a distortion because the drive wheel can’t move the same amount with a smaller diameter at one end than the other.

When you turn a circle in a car the outer wheels have to go further then the inner wheels… That’s just physics…

Generally, with tapered objects, the rotary is ‘tiled’, keeping the material in focus.


So RTIC 30 oz tumbler has a very slight taper on top section, leaving close to a 3" x 3" foot print.

Found that normal circle comes out too tall, so I turned off the LOCK for aspect ratio, and squished the top and bottom of circle by 11%, changing it from 100% to 89%.

This made the oval come out more like a circle.

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