Is this shudder ok?

I’m new to CNC milling - is this shudder ok? Should I adjust federate or plunge rate etc?

The wood is an Acacia, its quite hard. I have used the default hardwood settings.

I don’t hear a shudder. I hear the steppers moving. Each sounds different as they move left right then top bottom.

Do a walkthrough on your machine and check all bolts to see if any have worked loose.

Good luck, let us know


Thanks! I meant the sound of the bit moving across the flutes from the previous pass - glad you don’t think it’s a shudder. I was worry it was moving to fast.

I’ll check the bolts soon regardless.

If you are hearing funny noises during cutting as @Zman check the mechanics. Post your file. If you are cutting aggressively in hard wood you may need to slow the F&S down. If it is F&S that can cause the bit to go off course or lose steps and that can ruin the project. So the cost benefit of a failed project to a slower carve is something you would have to calculate for yourself but a completed project at a slower speed is a win in my book.


Thanks. F is feedrate and S is step over?

The job came out ok but the finishing could be finer. I read I could change to a smaller 1/16 ball end mill and/or reduce the step over to improve that?

When people reference F&S the F is federate and S is speed. As in the rotational speed of the router.

Yes, a lower stepover number yields better results but also higher runtime. For 3D work I have used a stepover percentage of 5-10 on the finish passes. I have done a few jobs where I used 1/8, 1/16 and 1/32 finishing passes. Those passes take very little material off so you can crank the feed rate up pretty good.

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