b'Users should benefit from more information about these popular toolholding components.By William Leventon draulic and milling chucks. Compared with these, the biggest advantage of ER C ollets are among the items mostcollet systems is their versatility, said Alan commonly found at machine shops.Miller, engineering manager at BIG KAI-But people who routinely use these tool- SER Precision Tooling Inc., Hoffman Es-holding mainstays probably dont have alltates, Illinois.the important facts about them. With the other options, youre really Thats because theres a lot to knowlocked in to one size toolholder for a spe-about colletsin a number of differentcific-size cutting tool, he said. But with areas. These include how collets stack upcollets, one holder size can hold a wide against other toolholding options and thevariety of cutting tool shanks. Especially latest in collet technology, as well as howfor smaller shops, that versatility will make to choose and use collets to extend theirthings easier.lives and get better results with machining. As an example, Miller pointed out that Placed in a chuck, a collet forms a collaran ER32 collet chuck can hold tool shanks around the tool to be held. The standardranging from 3.175 mm (0.125") to 19.05 ER collet is the most widely used tool- mm (0.75") in diameter with different col-clamping option for machining applica- lets. ER systems, he explained, include tions. Commonly used to hold endmills, drills, taps and reamers, ER collets exert clamping force when tightened with a nut. about the author Comparing Collets William Leventon is a contributing writer for Other well-known toolholding alterna- CTE. Contact him at tives include shrink fit and Weldon flat 609-926-6447 or wlevalso known as side lockas well as hy- [email protected] 2020 Toolholders.indd 28 5/14/20 3:01 PM'