The Test Cut

Woodworking Glossary

Collet

Router collets. The slits let the sleeve squeeze closed around the bit shank -- which is why a collet grips, and why a worn one stops gripping.
Router collets. The slits let the sleeve squeeze closed around the bit shank -- which is why a collet grips, and why a worn one stops gripping.

A collet is a split, tapered sleeve that grips a router bit's or spindle's shank when tightened, distributing clamping pressure evenly around the shank's circumference rather than pinching from just one or two points the way a simple set-screw chuck would. Router collets are the most commonly encountered example, sized to standard shank diameters (1/4" and 1/2" being the two most common), and a worn, damaged, or debris-fouled collet is one of the most common real causes of blade runout and bits working loose mid-cut.

Keeping a collet clean and free of resin buildup, and not over-tightening it (which can deform the sleeve over time), is basic router maintenance that directly affects both cut quality and bit safety.

Images

Router collets. The slits let the sleeve squeeze closed around the bit shank -- which is why a collet grips, and why a worn one stops gripping.

Product: Router collets. The slits let the sleeve squeeze closed around the bit shank -- which is why a collet grips, and why a worn one stops gripping.