Laser Engraver Forum

I want to do a complete wrapped etch on a powder coated tumbler, but for the life of me I can't figure out to size the design correctly. When I do a normal design on a cup I have to multiply the Y axis by 3.86 in order for it to look correct. I tried doing the full wrap that way, but it make the design to big for my laser. Example would be... if I do a 3"x3" design, I input 76mm X axis by 280.416 mm Y axis and it comes out 3x3 on the cup. I suspect the problem is I am using the method instead of knowing the correct circle pulse of the cup or hotdog roller I use. Can someone please HELP me figure this out and how to do it? Thanks

probably a clumsy back door method, but I do round objects so seldom keeping up with calculations is a problem.
I measure the circumference of the round object to be engraved and then make a template/box that size on the screen and fit the artwork to that size. Then I make the "3.86" calculation and run a test using the template/box only. If the template/box meets perfectly on the backside of the round object, I'm good to go. if it's off slightly I bump that "3.86" value up or down a little at a time until the edges of the template/box meet, then I know the actual engraving job will meet also as long as the artwork is the same with as the template/box. Just turn the template off and turn the job on. Like I said, most likely a clumsy way to do it, but it works.