[RESOLVED] Image came out skewed on tumbler


Hey everyone! I ran into an issue when I went to put an image on a tumbler and was wondering if anyone had any insight as to why it might of occurred.

I’m using an Rtic 30oz tumbler and the image I was using is my family’s crest. I set up the rotary tool and set the diameter on the rotate engrave to the measurement I took from the tumbler, however the final product (picture below) had the image a little too narrow (about 10%) on the tumbler. I was doing this on a stainless tumbler coated in Ceramark and set the scan mode to x_unilateralism.

Any thoughts on what I might have done wrong?


Did you flip the rotary switch on the laser??


Yeah, it was on. This was actually done during one of the tumbler classes, and we couldn’t identify where the issue was.


If the tumbler perfectly cylindrical, or is it tapered?


If the Thunder s/w check box is not selected, the image should be wider if I’m not mistaken.

Hmmm … If the center of the cup is placed directly lower than than center of the rotary tool, the image would effectively fit an area smaller than intended.

For instance let’s say your image subtends an arc of 30 degrees and your cup is 4" in diameter. Then the arc of you image is (30/360)2pi*(4/2)." Which is … 1.05."

And you measured a 10% smaller image … This gives a subtended arc of 0.945." This translates to an effective radius of 1.8."

So if for some reason the 2" radius of the cup was placed 0.2" lower than the center of the axis for the rotary tool, the cup with a 2" radius would subtend an arc 10% shorter than intended.

And the more I think of this, I’m fairly certain I’ve oversimplified this - to truly understand this one would need to see how the cup was attached to the rotary tool - and I know we have different options available to us.

Either way this is probably a decent approximation, and I’m guessing the center of your cup had not slipped 3/16" which sadly puts us all back in the dark.


The area that I’m working with is perfectly cylindrical.


If the drive motors are contacting an area with a different circumference then it will travel a different distance.


Problem was a flipped DIP switch on the rotary attachment. Switches are on the right end. Easy enough to flip one accidentally.

Settings are documented in the wiki. They are:

Rotary attachment functioning