High quality mt-er collets chuck sets mt-er collets holders also known as spring collet, is mounted on a drill / milling machine, drilling and milling chuck, its function is to clamp drill cutter or knife. Er flexible collet is currently the most used. Its stable performance, high accuracy by the majority of manufacturers trust. All products are precision grinding.specification1. Material: 65mn2. Hardness: hrc44-483. Progress steps 1mm or 1/64"4. Are 6 ditch way in front and back5. Sincerely service our teli mainlyinkindsofcollets, kindsoftoolholders, bttoolholders, cattoolholders, dattoolholders, nttoolholders, hsktoolholdersseries, boringheadseries, tappingcollets, livecenters, drillchucksseries, andsoon. Product show company information sishui teli tool co., ltd. Sishui teli tool manufacturing co., ltd locates in sishui economic developing zone.our products can be divided into 3 types: the first is various tooling system for cnc machinetools, includingprecision tool holders, spring collets, rough or precision boring heads and tapping collets;the second is otherstandard machinetool accessories, such as all kinds of live centers, drill chucks, etc.; the third is the special machineparts on cnc machine tools asclientss' samples