Collet Block Set (Hex/Square), ER-25

A collet block is a precision workholding device designed to securely grip and position cylindrical or hexagonal workpieces. Unlike traditional vises that clamp with flat jaws, collet blocks utilize a collet – a slotted sleeve with a tapered outer surface – that collapses uniformly around the workpiece when tightened. This provides a concentric and consistent grip, minimizing the risk of distortion or damage, particularly when working with delicate or thin-walled materials.

The collet block itself is typically a hardened steel block, often square or hexagonal, with a precision-machined bore to accommodate the collet. The combination of the precision collet and the stable block creates a rigid and accurate platform for a wide range of machining operations.

This SQUARE collet block provides easy indexing for 2 and 4 divisions.
The collet block is 1.48" square and the body is 2.7" long.

This HEXAGONAL collet block provides easy indexing for 3 and 6 divisions.
The collet block is 1.75" across the flats and the body is 2.7" long.

ER-25 collets have a have a clamping range of 1/16" to 5/8" (1.0 mm to 16.0 mm).

This spanner wrench fits ER-25 collet nuts (38-42 mm).