Identifying nuts and bolts for those odd projects can be confusing for the beginner, so I wanted to do a brief tutorial on nuts and bolts basics. I also wanted to show how a simple threaded hole is made and a repair that might give new life to something that is broken or worn out. For many of you, these will be things you already know, but I’ve found it difficult to get good basic information on things like this without lots of jargon and digression into specialized cases.
The following images will look at a grade 5 3 inch 3/8-16NC hex bolt. What does all that mean?
The length of a bolt is measured from under the head to the end of the threaded shank; in this case, we have a 3 inch bolt.
The diameter of the bolt is measured across the largest part of the threads. Bolts are generally made slightly smaller than their nominal diameter for ease of installation. Here we have a 3/8 inch bolt, and as you can see, it measures .370”. In theory this bolt would measure .375” there is a difference of .005, about the thickness of a hair.