While facing an issue during rotary scale settings on an Ikier engraver using ‘GRBL’, I found out a post saying that manual movement using the Move window or ‘Position Laser’ jogging controls are not subject to rotary scaling.
Why ??
As LB knows that a rotary is used with the ‘Enable Rotary’ switch, why LB does not scale Y axis (or whatever axis on which the rotary is connected) to take rotary settings into acoount for jogging controls in the Move window ?
Doing so will greatly help people trying to set-up their rotary 
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Don´t know if you already read the following docs:
Hi, thanks for your reply but, yes I already had a look at that before posting.
May be I missed something and if you can point me out the answer to my question in these two links I’ll be more than happy
Can you provide a link to that post? Not sure what you mean by “rotary scaling”. If I jog the Yaxis 80mm with the chuck rotary attached, it will make exactly one rotation, as it should.
@MikeyH
Here is the link : Post from NicholasL
What that is saying is that if you send a 100mm command to the rotary, it might move only 80mm. And Lightburn does no scaling for this. That is because the belt drive on the stepper to the chuck or rollers is an unknown ratio.
Lightburn has no way of knowing this ratio initially. So you do the Test rotation for 1 revolution and back. That is where Lightburn can learn the scaling referenced in that thread. And why that the Test Rotation is so important.
Hi Mike,
I fully understand that, that’s why Lightburn has a dedicated window to set chuck and roller settings.
What you don’t understand is that the chuck and roller settings are not took into account when you move it using the manual movement in the Move window, even with “Enable Rotary” button activated that says to Lightburn to adapt the Y axis distance …
You can do the test easily even if you don’t have a chuck or a roller.
Slide the “Enable Rotary” button in the laser window, draw a rectangle of 50mm by 50mm in the canvas, assign it to a layer with power at zero and click start, you will see the Y axis moving with a distance that will depend of the chuck or roller settings, that’s correct. Now go to the Move window set a distance of 50mm and click on the right arrow to move the Y axis by 50mm, result → the Y axis will move 50mm to the right, chuck and roller settings are not took into account. That’s all I want to say.
I cannot dispute this for two reasons:
- I have often had trouble with setting the rotary for good output to the part. I decided I was really not doing it right and to just suck it up. I even posted a test on the forum on the chuck and roller setup.
- I am in New York for the holidays and my machines are in Florida. I cannot do any testing until I get back.
There are a lot of postings about rotary issues. They usually fizzle out, but I am not sure why. Maybe they figured it out. Maybe they accepted their fate like I did.
Hopefully, someone that uses the rotary successfully will jump in and comment.
I just tested this on my diode machine and you are correct in your description of the behavior.
I framed a 200 by 200 square, then enabled rotary and framed it again and it was significanty smaller on the Y axis, more like 150 in my case. I then went to the move controls and told it to move 200 with the rotary enabled and it moved 200, not the ~150 that it moved when framing.
I think, if I understand the post referenced from @NicholasL correctly, this is because the move controls send the command directly to GRBL and do not go through the rotary module to translate. Obviously I don’t know if this is something that could be implemened or not.
All that being said, I have never found this to be an issue in actual use. I rotate the Y axis so the graphic will fall within the limits of my machine, place the tumbler on the rotary, move it to my desired start alignment if there is a handle or other object I need to consider. Move the laser head to the correct location on the tumbler, set the origin and start. I typically use User origin for tumblers.
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Hi Mike,
This is just a constructive post
For me, now, It is set up and used successfully, the problem is not there.
But during the setup of chuck and roller we are tempted to use the manual movement to verify the settings of chuck or roller, and settings does not have effect on manual movement, that’s all.
My original post was to ask why and to know if it’s normal and to let it know to others that may experience the same situation during chuck and roller settings.
I wish you all a happy festive season.
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This is good, and needed to be posted. Even if someone else does not get a solution from this thread, they have some contacts they can include in a new posting or to message.
This has me curious. I am still going to investigate this when I return home. 
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