ER50 series collets have a capacity of .218-1.339 inches. Each ER50 collet has a range of .078 inches(2mm). ER50 collets .500 and smaller have a range of only .039 inches. The size indicated on the collet is the largest size it can hold and can be collapsed smaller within its collapse range mentioned above. For example, ER50-5/8 can grab a round shank from .625 diameter to .547 diameter. Please refer to our ER50 Collet print for general ER50 dimensions.
