Q: What is bolt grip length vs the threaded length? And which is the total length of the bolt?
A: Neither the grip length or threaded length provide information on the overall bolt length. The length of the bolt is always measured from under the head of the bolt to the base of the shaft. The only exception to this rule is for a flat head screw. On flat head screws the length of the bolt is measured from the top of the flat head to the base of the bolt shaft.
The grip length is the unthreaded shank of the screw. This is measured on all bolts (except flat heads) from under the head to the start of the threaded section. Though some people ask for a grip length it is more common to request the total length of the bolt then specify the threaded section. For example, you may request a 3/4″-10 x 3″ Long bolt with 2″ of threads. On this bolt the grip length will be 1″ since it is the portion of the bolt under the head that is unthreaded.
