With routing and CNC, alot of it comes down to feeds/speeds, the bit quality, and the machine's structural rigidness. I would start by slowing your machine down some or your router. If you're making dust and not chips, you're overheating the bit and burnishing/compressing the wood. That makes for a bumpy ride. Next I would try and figure out if there are any loose bolts or play in the machine. That's a mad man quest though. Every machine has some play. You're looking for something obvious. If nothing else works, try a new bit. I bet it's your speed though. Must ppl think you want to run wide open. Not the case. When there's a bit of resistance to the cut (only a little), the cut is smoother. Hope that helps. It's not exactly a cnc, but I very some of those things affect both. Something else to think about.. does it only chatter some times? If so, when does that happen? That could help in diagnosing your issue.
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