ER Collets Size range: ER Collets is an external collet is an sleeve with a (in general) cylindrical inner surface and a conical outer surface, and act as a subtype of chuck that forms a collar around an object to be held and exerts a strong clamping force on the object when it is tightened, usually by means of a tapered outer collar. Collet system designed to hold a workpiece or a tool. ER Collets explained, it have a narrow clamping range and a large number of collets are required to hold a given range of bits, however the collet's advantage over other types of chuck is that it combines all of the following traits into one chuck; making it highly useful for repetitive work. ER collets contract over a range of 1mm and are available in 1mm or 0.5mm steps except ER50 Collet system range have 2mm steps, so a range of ER collets can hold any cylindrical shank, metric or imperial. ER collets may also be used on a lathe to hold work pieces, Lexis tooling ER Collets are designed to unclamp one part and switch to new part and reclamp easily, its reliable for Self centering, strong clamping, hence our collet chuck can deliver all reliably, and with no need for a skilled user do depend on the object being clamped closely matching the size and shape of the collet's clamping surface. This constraint is usually not a problem when the object is good-quality bar stock; the shank of a well maintained drill bit, reamer, end mill, etc.; or a previously machined part that is being rechucked for additional cutting operations. ER16 Collet Sizes designed with 1mm steps ER20 Collet Sizes designed with 1mm steps ER25 Collet Sizes designed with 1mm steps ER32 Collet Sizes designed with 1mm steps ER40 Collet Sizes designed with 1mm steps ER8 Collet Sizes designed with 0.5mm steps ER11 Collet Sizes designed with 0.5mm steps ER50 Collet Sizes designed with 2.0mm steps