ER COLLET CHUCKS & COLLETS Solid locknut Solid locknut slim design Bearing locknut* (Standard Solid Locknut) (Optional Slim Locknut) (Optional Bearing Locknut) The Standard Solid Locknut is balanced by design and compatible with all ER collet types. Optional Slim Locknut for ER Chucks (sizes 11, 16, and 20) offers a narrow profile, allowing machining in limited spaces. Optional Bearing Locknut improves runout and grip, enhancing tool life - ideal for demanding applications like Solid Carbide End Milling. E15 kennametal.com