A Chatter mark is one or, more commonly, a series of marks made by vibratory chipping of a bedrock surface by rock fragments carried in the base of a glacier. Marks tend to be crescent-shaped and oriented at right angles to the direction of ice movement.

In machine tools a chatter mark is an irregular surface flaw left by a wheel that is out of true in grinding or regular mark left when turning a long piece on a lathe, due to machining vibrations

Machining vibrations

Machining vibrations, also called chatter, correspond to the relative movement between the workpiece and the cutting tool. The vibrations result in waves on the machined surface. This affects typical machining processes, such as turning, milling and drilling, and atypical machining processes, such...

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