b'People get the idea that tighter is better, but thats not the case.Collets Up Close somebody torques down (the nut) by hand and then grabs a hammer and gives the wrench a couple of hits just to make sure the nut is really tight.tightening torque recommendations for different ERDoiron cited another bad but fairly common prac-collet sizes. tice: overextending a tool held by a collet to make the Torque wrenches arent used to tighten collet nutstool reach a little farther, thereby sacrificing critical in most cases, Moon said. But shops can get satisfac- gripping force.tory results using a spanner wrench. To extend the reach of a tool an extra 12.7 mm (0.5"), Generallyabout152.4mm(6")long,spannerpeople will push that tool out to the very end of the wrenches for ER collet nuts are designed to keepholder, he said. Its as if you were holding a stick with you from imparting a giant amount of torque to thosethe very tips of your fingers versus holding it with your things, he said. But shops get into trouble whenhand.CRITICAL CONNECTIONMatch toolholders with the correct applications.By David McHenry toolholding technologies, such as those developed by Rego-Fix Tool. Its original ER clamping systemcom-T oolholders are the critical connection between aposed of an ER collet holder, a collet and a nutis en-cutting tool and a machine tool spindle. Toolholdergineered for traditional machining applications while performance dictates productive output, surface fin- its powRgrip system is aimed at high-speed milling and ish of a part and the life of a cutter. With the right tool- drilling and other high-performance applications. The holder for the application at hand, a shop maximizeslatter system consists of powRgrip toolholders with in-benefits from high-performance cutting tools and ma- ternal tapers that accept the matching tapers of powR-chine tools. grip collets. Tools are inserted into and removed from Different toolholder types provide different levels ofthe holders using a fast-acting manual or automatic hy-performance. Depending on the machining application,draulic powRgrip unit.some performance factors are more important than oth- For tougher machining operations, secuRgrip tool-ers. For precise work, a low total indicator runout mayholders are made to fit powRgrip clamping units and be most important. When multiple setups are involved,prevent cutter pullout. This method utilizes a patented quick-change capability is essential to maximize pro- locking system and threaded cap, with the key element ductivity. In heavy-cutting situations, tool retention forcebeing a special collet configured to accept a threaded might be emphasized. And in most operations, the costinsert that locks into the Weldon flat on any tool with of the tooling system itself is a significant factor. that feature. The system has a total indicator runout of When it comes to the various toolholders and their0.00254 mm (0.0001"). No tool shank modification is re-qualities, ER collets are known for gripping strengthquired, and existing powRgrip holders can be modified and accuracy. Collets in the ER system, which was intro- for use with these holders.duced in the early 1970s by Rego-Fix Tool Corp., Whit- At the opposite end of the toolholding size spec-estown, Indiana, and later standardized as DIN 6499, supply a wide clamping range and high accuracy over an extended selection of operations. about the author Most shops select toolholding systems based on theDavid McHenry is engineering and parts being made and how they are manufactured. De- technical manager at Rego-Fix Tool pending on the product mix, shops generally use moreCorp., Whitestown, Indiana. For more than one holding system. An effective way to simplifyinformation, call 317-870-5959 or visit toolholder selection and acquisition is with a family ofwww.rego- x.com.32JUNE 2020Toolholders.indd 32 5/14/20 3:01 PM'