Noise variation

I have a variation in sound / vibration as while my mill is moving +x vs -x directions. There seems to be a higher pitch ringing and vibration when moving +x.

I am milling a piece of 1/2" birch ply with the 201 1/4" cutter. S/F are the suggested ones from CC.

Is a variation in sound normal? Do I need to tram the machine?

Mine sounds like the computer from Willy Wonka

I think it is normal for each machine to sound a bit different. And for different sounds when moving different directions. The sound comes from a stackup of parameters in the kinematics chain that result in resonances. Change up the feeds & speeds a bit and the sound changes.
If you were machining microscopic parts at really high tolerances you might want to find a combination that has the least resonance. Similar to the way machines get tuned for very high-speed machining to get the best finishes.
For the stuff we typically do on these machines, I don’t think it makes a difference.

Now if it were awful grinding, rubbing noises I would be concerned.


You can play music using the stepper frequencies, and of course someone has made a midi-to-gocde utility. No matter how crazy the idea is someone on the internet has probably already implemented it:


Wood density varies with changes in grain direction. Cutting with the grain sounds different from crossing the grain.


Good to know. This was only moving along one axis so it was either both with the grain or both against the grain, or some angle of it.

I forgot I took a video of it.

Cutting back & forth like that (Zig-Zag, Lace, Raster) is switching from conventional to climb cutting on every other pass. Climb cutting tends to push the cutter away from the material whereas conventional cutting draws the tool into / toward the material. Of course if the machine is rigid enough you won’t have any measurable deviation, but the forces are still opposing & will create a different sound.


Makes sense. I Don’t have a lot of experience with CNCs so I appreciate this community.


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