Metal Smears

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Metal smear on a tool

This type of trace deposit might be found on the operating surfaces of tools. Metal smears may be observed under the microscope by a toolmark examiner and, if probative in nature, referred to a metallurgist. If a toolmark comparison is inconclusive, these minute deposits could at least be shown to be consistent with a toolmarked surface.

Note:

Examiners should be cautioned that relating a metal smear or other source of metal to a particular source based on a compositional comparison of trace elements present is not a viable option. This approach has been attempted, but all such past comparisons are under increased scrutiny and review. Many laboratories have discontinued the technique.

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