You may recognize the collet in an X-Acto knife. The blade of the knife is held in place with a collet. This is just a basic collet. In machining, collets are generally sturdier, made from hard steel, and they come in a variety of sizes. The type of collet that you need depends on a few different factors, including the type of work that will be done and the size of the bit or object that will be held.

Types and Styles of Collet Chucks

There are many different types of collet chucks, but two are used most frequently. They include:

• Pull-back Collet Chucks: These collets are pulled back into the tapered spindle, causing the collet to clamp onto an object. As the collet is pulled back, the spring jaws are engaged, effectively gripping the work. The jaws are tapered toward the chuck.
• Push-Out Collet Chucks: These collets are pushed forward, away from the spindle, to grip an object. Essentially, they are the inverse of the pull-back, and the jaws are tapered toward the object.

Other popular collet chucks include multi-position chucks and dead length collet chucks, which are used for applications in which users need additional precision.

Choosing the Right Collet Chuck Size

Size is very important when choosing a collet chuck. There are two measures to pay attention to. The first is the diameter of the collet, which is often measured in a range of diameters measured in millimeters. The most popular measure is the “ER” system, which includes a range from ER8 to ER50.

The number represents the number is the size of the collet opening, measured in millimeters. For example, for larger work pieces, you would require a collet with a larger diameter. Some of the most commonly used collet sizes are the ER16, ER20 and ER32.

Secondly, you’ll need to consider the taper of the chuck. Chucks are designed with a male taper that fits into the female machine or power tool spindle taper. Thus, the taper size of the collet chuck you purchase should match the taper size of the spindle or machine shank that you’re using. One common measure is the NST or NMBT shank measurement system, which includes the most common NST 30, NST 40 and NST50 sizes. There are various other taper systems, so be sure that your taper matches.

Common Collet Applications

There are many different uses for collet chucks, and the type of collet you use depends on the type of work that you will be doing. They can be used in metalworking and woodworking. Most commonly, collet chucks are used to hold work pieces, bits and other objects in place for:

• Drilling
• Milling
• Boring
• Tapping

Shop for quality and affordable collet chucks on Deelat.com. We feature a wide selection of collet chucks, including ER type chucks, made from quality materials.