Shapeoko 3 Better, but border cut still out of square

Has anyone had problems with a straight cut running out of square? As an example, if I make a 12" long by 5 1/2" sign (using oak) and run a v bit for the boarder I get an out of square cut on the X axis. I have squared and leveled my machine frame and checked the x and y axis to make sure everything is as it should be but I still get a 1/16" inconsistency. I make sure the material I’m working with is square. I don’t see or hear any skipping of the belts either. I have been testing G-Wizard and being on the conservative side on the feeds and speeds but I wonder if the z axis plate is flexing enough to cause this problem?

Also to note, I check and recheck that the work piece is squared to the frame and gantry. I’m out of ideas at this point.

Thanks to everyone for any input.


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Do you use the limit switches? I noticed that my machine is square when power is off but when it runs to the rear limit switch the side without the limit switch hits first then it cocks the X axis beam until the limit switch hits. That means it locks itself out of square after homing. The solution is to make sure the limit switch side bottoms out first but I can’t stand to wait for the machine to spend over a minute homing so I just don’t use them. I just have a 1/4" hole in my spoil board that I use as a home if I have a project big enough to worry about losing zero. Sometimes I just put a hole in the project material and just use that as my zero.

So, check to make sure your homing operation isn’t causing the x axis to rack.

I do have and use limit switches on the machine Tony. I did check as you said and it seems that is not the case. However, while doing more measuring, I was measuring 1/16" from the back of the gantry support plates to the back of the side rails plate. While the machine was on (braked), I jerked the left side gantry forward, measured again and ran it around after homing and it seems to have done the job. I even turned everything off and started the whole process over and everything seems to be good to go. Maybe not the best approach but at this point I would have taken a hammer and chisel to get this thing right.
I don’t know if while the machine was off and changing a bit I moved the left side and got it out of sync with the right side or not. Will run a test tonight and see how it goes.

Thanks for your help Tony.

is there a proper way to correct this when the two sides are out of sync. seems to happen to me a lot because i can’t seem to break myself of the habit of moving the machine manually when it is powered off.

The proper way to handle this would be to have the ability to drive the two Y-axis motors separately. Not an option w/ the CM controller since it drives them in tandem.

Don’t move the machine by hand once it’s homed and squared up.

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I have a simple rule: NEVER more the machine my hand, never. That’s what Carbide Motion is for, but that;s my rule and it works great.

sometimes it just seems like a lot of trouble to use the software to move the machine just to clean the tops of the rails and check for debris.

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