Capacity is not the hole size, however is directly related to the hole size.
Capacity refers to the outside dimensions of the collet.
Capacity = Maximum hole size.
For example, a 3/8 capacity collet is availble in many different hole sizes, up to 3/8".
Refer to the table below to find the proper capactiy of your collet
CAPACITY | RANGE | TYPE | D | L |
1/4 | 1/16 - 1/4 | OW | .39 | .50 |
3/8 | 1/8 - 3/8 | WW | .59 | .75 |
1/2 | 1/8 - 1/2 | Y | .80 | 1.06 |
3/4 | 1/4 - 3/4 | Z | 1.12 | 1.50 |
1" | 3/8 - 1" | ZZ | 1.56 | 2.00 |
1-1/2 | 3/4 - 1-1/2 | XZ | 2.20 | 2.50 |