Even if you’re an expert, it’s always a good idea to review the basics. Here, the essentials of selecting and installing threaded fasteners are covered.
Do you know how to measure bolts? Are stainless steel fasteners the best choice for your build? What lubricants should you use with your nuts and bolts?
Some of us builders know these answers as surely as we know our own names, while others are still learning fastener basics. Regardless of your level of expertise, this fastener primer will provide you with some practical information you can use in your shop today.
1. Bolt Diameter
Bolt (or stud) diameter commonly refers to the “nominal” thread diameter. For instance, a 3⁄8-inch bolt shank should measure 3⁄8 inches (0.3750 inches) in diameter. Remember, bolt diameter refers to the thread or shank diameter, and this size has nothing to do with the size of the wrench required to service the bolt or nut. If you hear someone refer to major and minor diameters, here’s the explanation: major diameter refers to the diameter of the thread crest (the largest outside diameter of the thread) and minor diameter refers to the diameter of the root (the deepest part of the thread).
2. Bolt Length
For most styles of bolts/screws, the published length of a bolt refers to the length of the shank/threads from the underside of the bolt head to the tip of the shank. This applies to styles such as hex-head bolts, 12-point bolts, socket-head cap screws and button-head screws. However, a flat-top screw (flat on the top and chamfered under the head) is always measured at its overall length.
Tags: Fasteners, Mike Mavrigian, Tech Tips











