Tolerances for inlay

Hi everyone. I want to inlay a 3 mm piece of acrylic into three-quarter inch birch. It’s like an 18 inch circle. What should my tolerance be for my CNC pocket? Like a half a millimeter or a millimeter? Thanks!

A .010 gap works. Test your cuts on scrape material. I had to fake a bit size due to under cutting.

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A hundredth of a millimeter? That sounds… not right. Do u mean a hundredth of an inch?

Yeah… that’s about a quarter mm which is what I was thinking… so a circle would need a pocket diameter 0.5mm more to give that 0.25 mm clearance on all sides

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What type of fit are you looking for? Press, Interference, Slip???

18" is 457.2mm. Cut it 457.0 & see if it fits.
Then step up your dia by whatever tolerance you’re comfortable with, say 457.25mm
Keep stepping up the dia until it fits.

If you’re looking for a slip fit, you’ll probably end up right where Jim suggested, at about 457.75mm

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I offset the shape by .3mm on all sides.

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