What Is A Collet?

collet refers to a type of holding device, similar to a chuck. It’s used to keep an object firmly in place. As it’s tightened it exerts a clamping force upon the object it is holding. Collets are frequently used to hold a workpiece or tool in place.


A collet has the appearance of an external sleeve. The inner surface is usually cylindrical and the outer surface is usually conical. It may be squeezed it to contract its inner surface to a smaller diameter to clamp an object in place. This type of collet is called a spring collet because it’s made from spring steel. A variation on this design is a collet which is comprised of a number of tapered gauge steel blocks held together in a star configuration by flexible rubber.

Whichever collet design you choose to use, each one operates on the same principles. You simply squeeze the collet against the workpiece or tool you wish to hold. The resulting high-static friction will hold it securely in place.

Collet Maintenance

  • Check parts that have regular metal-on-metal contact. Do not use collets that are scratched or worn as these will not have an adequate grip.
  • Don’t tighten your collet without a bit in place, this will shorten its life.
  • Clean collets regularly to remove build-up of dust and pitch, to ensure a tight fit on the bit.

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