3/8 (5/16 BSF)x2 1/4 SKT SHOULDERBOLT

Socket Shoulder bolts are fasteners that have an unthreaded portion of the shank that functions as a bearing surface or spacer.
These are measured by the Shoulder Only, for this size the shoulder diameter is 3/8, the length of the shoulder is 2 1/4" and the thread on the end is 5/16 BSF
It is important to note the threaded portion is NOT included in the length.
They have an in-hex drive and are fastened using a hexagonal wrench also known as an Allen key.
Thread = 5/16 - 22 TPI

GST Incl
Excl
3/8 (5/16 BSF)x2 1/4 SKT SHOULDERBOLT
SHBBSF038214B
Each
$17.1500