Imperfect circle

When I’m cutting I am getting imperfect shapes. It seems to be on pockets and inside cuts when the y-axis is moving backwards/to the back of the machine. There doesn’t seem to be as much issue on outside cuts when the y-axis is moving to the front of the machine.

I have flattened the bed and there are no signs of being poorly trammed. I have also reviewed the flatness with a makeshift guage and the spindle seems pretty straight to the bed.

There is no noticeable backlash.

There is noticeable play on the gantry—the bottom has wiggle room against the x-axis rail. I have adjusted the eccentric nuts as much as I can but there still seems to be horizontal play. Would some washers in there fix it (and fix my issue)?

Any ideas on how to troubleshoot or fix the issue are welcome :slight_smile:

@ryanprice You should not need to add washers to fix things, Ryan. When you say that there is noticeable play/wiggle room, can you explain a bit what you do to feel that? Do you mean that you can move the X gantry forward and back along the Y axis? If so, you need to adjust the anti-backlash nut on each side. Make very small adjustments until there is no play at all.
Of course, I could be missing the problem entirely. If so, please try to enlighten me. :grinning:

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@gwilki The gantry moves perpendicular to the y axis rail. I recorded a clip to show the movement but can’t attach it, so a link will have to suffice, I guess: Dropbox - - Simplify your life

I can see the gantry shifting when cutting and figure this is a major factor in my less than ideal cuts

@ryanprice Whoa! Big time movement. I know that you said that the wheels are adjusted as much as you can, but they are not tight enough. Try this. Lift straight up on the router mount. While doing that, try to turn the X gantry wheels. I would bet that they will turn very freely. The problem is that the weight of the router and the Z gantry makes them feel tight, when they are not. You need to take the weight of them while setting them.

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@gwilki The problem is the eccentric nuts are maxed out and there is still that slop. No idea where to go from here

@ryanprice Two things:

  1. Another user on here found that he had mounted the Z gantry incorrectly on the X gantry so that the wheels were not running along the edge of the aluminum angle. He had the same cutting issues as you are having. You can look to see if yours are OK.

  2. If all is well there, contact Sienci support. Some time ago, there was an issue with delrin wheels being too small. It was not possible to to get things adjusted properly because of that.

Thanks, @gwilki

The wheels seem to be seated correctly, so I guess i’ll contact support and see what they say.

Turns out I did indeed end up with a set of undersized v wheels—Sienci was quick to reply to my email and immediately had the issue figured out and are sending me a new set of wheels so I no longer wonder why my circles are lopsided :wink:

Great support from Sienci and @gwilki — Thank you all!