Possible small bit, small hole issue

I am using Kiri:Moto with Onshape and a cheap 3018 desktop router. I am cutting light plywood using a 1/16" bit. For the most part, it has been BRILLIANT! I have noticed a possible issue (possibly user error) when trying to mill small holes. I was trying to mill a 3.8mm hole for a part, and the actual run AND the preview and animation in Kiri:Moto resulted in a kidney-shaped hole instead of a fully round hole. I only got maybe 2/3rds of a complete hole. I increased the holes up to 3.9mm and it was better, but still had a bit of kidney dip in about 10% of the hole. Increasing to 4mm resulted in round holes. I have seen this issue multiple times with small holes. It seems wholly dependent on the size of the hole as larger holes are perfect.

Is there a setting somewhere I am missing, or some setup with the tool that I need to change?

cheap 3018 routers are inherently difficult when it comes to precision. they are not rigid, so expect flexing and inaccurate dimensions. you. can try running a much slower feed-rate and/or shallower depth of cut to see if that helps.

Yea, I have tried it very slow and with shallower depth. But, I think you missed an important part of what I said. The kidney shaped hole shows up in the animation as well, before ever sending it to the machine

if you think there’s a bug, please right-click export the .kmz workspace and DM or email it to me [ sa at grid dot space ] so I can debug. thanks!

Stewart was able to help me with a resolution for the issue I was seeing. I thought I would post it here in case anyone else was seeing something similar.

“Because this is a simple 2D cut, you could do the entire part with outline (settings attached). And that does not seem to suffer from this issue. Alternatively, if you change “detail” under “slicer” in the preferences menu to 75 or 100, it resolves the roughing issue.”

I was doing a roughing operation to remove interior areas, then an outline. Both of these solutions worked perfectly.

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