Rotary Tool and settings on Meerk40t

Hello, I have recently gutted my machine to accommodate a rotary tool.
The rotary tool is from Ortur, and came with my diode, but never really used it. Bought a cable online, as the one supplied had a different board connection, and was happy to find that it actually worked.

I tried to do a burn with the default X=1.0 Y=1.0 in Meerk40t, but the name came up too big. Had a look online and found some info about a “factor” and according to google, the formula should be smaller cylindrical object in my case 20mm roller diameter, divided by bigger cylindrical object, 61.5mm jar diameter = 0.3252
after inputting this number into the Y section, I got the word from 38mm on screen to 26mm on the jar…So that didn’t work.

I’m sure I can change the factor, and keep burning till i get the same size on the jar, but is not something that I would like to do for every different diameter object.
How you guys do it?
Thanks

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Same answer as in facebook: I am tracing a rectangle and mark the max extensions and then measure - that gives me the ratio to use.
I admit it’s not elegant but it works all the time. We will have a look at it to make it more user friendly. But my day has only so many free hours and I am living on borrowed time with my wife…

Thanks for the reply.

Do you mean you burn the rectangle without changing anything to the Y setting? Than check what is the difference from the design measurement to the burned measurement?

I appreciate all the work that must be going into Meerk40t also considering that is a free software…
I will try that, but I have to be honest, this solution might work if you are running a batch of the same items, and you sacrifice one to find the right ratio, but not ideal if it just one item, or different items with varying diameters…I’m sure there must be a better way. I’m not even sure if the formula i found on Google, is even correct, or if will have to take into consideration the type of stepper motor used?

I don’t damage/preburn any article - here’s what I do:

  • I need some painters tape and a (felt) pen.
  • I apply the tape to the to be engraved object. and put the object on the rotary.
  • I mark the top most position on the object
  • I ask meerk40t to move 5cm in the y direction (thats my rotary axis)
  • The object rotates and I mark again the topmost position
  • I then measure the distance between my two marks and divide that distance by 5cm → and you have your factor

…Drumroll…
I will put that in a explanatory box and will then derive the stepper motor factor from the rotary diameter, the object diameter and the measured distance. For the future the stepper motor factor and the rotary diameter will be stored, so that for future rotary burns the object diameter is then the only new value you need to provide.

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Giving it a second thought that’s not necessary - the factor will always remain the same. After you have established the factor in the first place a change of the object (diameter) will only be relevant to establish your burnable area before things overlap.

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Your suggestion worked :+1:
Although i divided 5 by 10, and input 0.5 in the Y scale
Did a burn of a 30mm word andbit came out perfect.

Tried to do a circle and it came up all messed up…


That’s on a wine bottle. The body was on the rollers, and the neck touching the machine frame.
The two photos are of the circle L20mm x W22mm
Wider to compensate for the round shape, according to a youtube video.

I can only think that the rotary moved, but it looked pretty parallel, and the second one is a lot more elongated than the first