Chattermarks are distinct, repeating ridges left behind on a workpiece when the cutting tool, machine spindle, or the part itself vibrates during a cut. They indicate poor rigidity, incorrect feeds and speeds, or excessive tool overhang. These marks ruin the surface finish and often mean the part fails inspection.
You can see the chattermarks on the face of this flange where the tool started singing.
You can often feel a chattermark with a fingernail before you can easily see it under shop lighting.
Related terms
Chatter
Self-sustaining vibration between tool and work that screams, leaves a wavy pattern and kills tools.
Surface plate
A thick slab of granite or cast iron, lapped flat, that every height check and layout line is measured from.
Feeds and speeds
The spindle speed and feed rate chosen for a cut, set from material, tool and machine.