Machetes: Sharpening materials and methods – Producing different striation patterns on bone

Abstract

As forensic anthropologists play a larger role in post-mortem examinations, the examination and interpretation of skeletal trauma resulting from sharp, blunt, projectile, and thermal injuries have become of critical importance and may assist in medicolegal death investigations. Although there is a plethora of research on sharp force trauma on bone, at present, there is little research regarding the striations produced by large bladed weapons on bone, whether those striations are weapon-specific, or whether they are the result of sharpening materials and methods. To test whether striations are weapon type specific, this study aimed to examine if different sharpening materials and methods produced different striations on the kerf walls of cut marks on bone produced by machetes. Or, if they do produce the previously identified ‘rolling hill’ striation pattern. Four factory machetes sharpened by the same manufacturer were re-sharpened using a wet stone, a bastard file, and a coarse and medium-grained machine grinder. The bones and casts were subjected to both macro and micro analyses, and the results identified clear differences in the shape of striation ridges and troughs, indicating that striation patterns are not weapon type-specific. The study's findings have opened up a new area of research into weapon types and the analysis of associated striation patterns and may aid in the identification of weapon types and the materials used for maintenance or sharpening, potentially offering additional evidentiary evidence.