How to Measure Size
How to measure specific types of fasteners:
Bolts and Screws:
For all bolts and screws except countersunk screws, the length is measured from under the head. For countersunk bolts and screws, the length is the overall length (OAL).
Clevis Pins: Measure length from beneath the head. This will be the length of the clevis pin as reflected in the Item Number. For instance, CLP124 is a clevis pin, 1/2" diameter, 4" long (measured from beneath the head). The effective or usable length of the clevis pin is measured from beneath the head to the top of the hole.
Cotter Pins:Measure length from beneath the head.
Flat Head Bolts:Flat head bolts (also called countersunk bolts), are measured on the overall length of the bolt.
Hex Head Bolts:Hex head bolts are measured from under the head to the end of the shank.
Safety Pins:Order using the diameter and overall length (OAL) and industry #. May be beneficial to call our Help Desk during normal business hours.
Socket Shoulder Screws:Order by the diameter and length of the shaft. The thread size defaults automatically to the next smallest diameter.
U-Bolts:Order using the pipe size the u-bolt will be used to hold.

May be beneficial to call our Help Desk during normal business hours.