Nuts & Bolts in Salt Lake City

Match the thread before anything else

A bolt that looks close is not necessarily interchangeable with the one you are replacing. Diameter and thread pitch are the first things to identify. Inch fasteners are commonly described by nominal diameter and threads per inch, while metric fasteners use nominal diameter and thread pitch in millimeters.

If you are unsure what you have, bring the original bolt and mating nut to our counter. A sample makes it much easier to compare thread size, pitch, head style and length. Our guide on measuring and identifying a replacement bolt or screw walks through the basic measurements.

Coarse and fine threads

The same nominal bolt diameter can be available with different thread pitches. Coarse and fine threads are not interchangeable, even when the outside diameter is the same. Forcing the wrong thread into a nut or tapped hole can damage both parts.

When you are replacing an existing fastener, match the original thread unless the application has been intentionally redesigned. For more detail, see our guide to coarse threads versus fine threads.

Length, head style and fit

Length should be measured from the correct reference point for the head style. Most bolts are measured from beneath the head to the end of the fastener, while countersunk fasteners are typically measured over the full length. Also pay attention to whether the original has an unthreaded shank or shoulder.

Head style can matter because of wrench access, clearance around the assembly and how the fastener seats against the part. If the hardware must fit through a recess or under a cover, bring those dimensions or the original part with you.

Strength, material and finish

Dimensions are only part of selecting a replacement. Bolt grade or property class, material and finish may be important to the original design. Head markings can help identify strength specifications, and corrosion exposure may affect material or coating requirements.

For vehicles, machinery, structural work, lifting equipment and other safety-critical applications, use the equipment or engineering specification when available. Matching appearance alone is not enough when the fastener carries a critical load.

Complete the assembly

Nuts and bolts often work as part of a larger fastener assembly. The correct nut, washer and locking method can be just as important as the bolt itself. If you are replacing multiple components, bring the complete assembly when practical so the parts can be checked together.

Fastener Engineering also stocks washers and other industrial fasteners for maintenance and fabrication work.