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 | D | Z | L |
3/8 | 1/16 - 3/8 | 0.562 | 0.31 | 0.83 |
1/2 | 3/16 - 1/2 | 0.720 | 0.39 | 1.09 |
3/4 | 1/4 - 3/4 | 1.131 | 0.54 | 1.75 |
1" | 3/8 - 1" | 1.446 | 0.69 | 2.19 |
1-3/8 | 5/8 - 1-3/8 | 1.909 | 0.72 | 2.69 |
1-5/8 | 3/4 - 1-5/8 | 2.125 | 0.76 | 2.69 |