b'Collets Up Closeager for milling and toolholders at Guhring Inc., Brookfield, Wiscon-sin. He added, however, that this flexibility is limited to a small range, which can be anywhere between 0.5 mm (0.02") and 1 mm.A Looser GripOn the downside, Miller said ER collets fall short compared with other toolholding options when it comes to gripping strength. As a re-sult, he said, ER collets are not well suited for high-torque cutting. So his company mostly recommends them for finish milling, drilling and reaming applications.A problem with ER collets in this regard is what gives an edge in flex-ibility to them over competitors:Emugetheir compressibility. FPC Slim Line collet chucks are designed to make it easier to use cutting tools in confined work When you have a larger amountareas.of collapsibility, there is more roomin with relatively light milling appli- If you need to hold on to a18 " end-for runout to be introduced andcations, Moon said, if we can getmill or drill, you want to use a18 " col-quite a bit more room for instabil- them to move to a hydraulic, millinglet even though there is some flexibil-ity or chatter, Moon said. So foror shrink-fit chuck or even a side- ity in that size, Moon said. The more high-performance applications, es- lock holder, they can double theirthe collet compresses, the more run-pecially being a milling guy, I gener- tool life because the tool isnt mov- out youre going to introduce.ally do whatever I can to steer peo- ing around as much in the chuckShops that want to use collets ple away from an ER collet chuck. and you dont get the chatter. but dont want the compressibility He added, though, that manyFor shops set on using ER collets,of the ER type may want to consider people use ER collet chucks for lighthe said the best way to optimizeFPC collets sold by Emuge.milling. performance is to closely match col- Ourcolletshaveaminimal But even when customers comelet size with tool shank diameter. amount of flexibility, following ISO The PJC straight collet is a reduction sleeve for small-diameter cutters with peripheral coolant supplies.BIG KAISER Precision Tooling30JUNE 2020Toolholders.indd 30 5/14/20 3:01 PM'