Milling Collets Appraisal

ER-Style Collets

This appears to be a collection of collets, specifically likely ER-style collets due to their distinctive knurled gripping surface and stepped cylindrical shape, stored loosely within a cardboard box. The collets are uniformly black or very dark gray, suggesting a treated metal surface, possibly black oxide or a similar protective coating, common for tool steel components to prevent rust and reduce glare. Each collet is cylindrical with a visible internal bore. They feature a knurled band around their circumference, designed to provide a secure grip when inserting or removing them from a collet chuck. Some collets exhibit faint numerical or alphanumeric markings on their body, indicating size or manufacturing details, such as 'ER-20' visible on one item, confirming their type. The condition of the collets varies; some show visible signs of wear, light scratching, and minor discoloration consistent with use in a workshop environment. There is no significant rust or heavy damage visible, suggesting they have been reasonably well-maintained despite being stored in a utilitarian manner. The craftsmanship appears to be industrial standard, with precise machining evident in their uniform shape and the clean knurling. The lack of elaborate finishing suggests they are functional tools rather than decorative items. Their estimated age is difficult to pinpoint without clearer markings, but based on their common design, they could range from relatively modern to several decades old. There are at least seven individual collets visible in the box, suggesting a set or a collection of various sizes.