Bolt Head Types and Practical Uses

Fastener options are almost limitless. The various shapes and sizes and the practical uses for each different type can be confusing. To get more specific, the differences between a screw and bolt are almost zero. Although not always true, it’s generally accepted a bolt passes through a substrate and takes a nut on the other side while a screw takes no nut because it threats directly into the object.

In regards to bolts, the types range from the fairly common hex bolt to the more unique hanger bolt. But which is the right one for the specific job you’re currently in the process of completing? Below is a description of a few different bolt head types and how they can be applied.

Hex bolt: a bolt with a hexagonal head and machine threads for use with a nut or in a tapped hole. Also known as hex cap screws or machine bolts.

Carriage bolt: a bolt with a smooth, rounded head that has a small, square section underneath. This makes the bolt self-locking when placed through a square hole or a round hole in most wood. It can be installed with only a single tool (spanner or wrench) working from one side.

Lag bolt: a bolt with a wood thread and a pointed tip.

Eye bolt: a bolt with a circular ring on the head end. Used for attaching a rope or chain.

At Elgin Fastener Group, we have vast amounts of experience and expertise creating bolt solutions, including place bolts. What’s a place bolt? It’s a one-piece, free-spinning, all-metal, self-locking hex bolt. Its unique head design provides the locking action. This is important because not only does it provide the bolt more elasticity, but also serves to produce up to seven times the vibration life of conventional hex cap screws. These cold-formed fasteners are not only strong and durable, but reusable as well.

The place bolt is manufactured at Elgin Fastener Group with five or six slots in the head. The six-slot is used for customers like General Motors in the automotive industry in such places as the Allison transmission. The five-slots are for our military distributors and are sold as a grade 5 or grade 8.

The place bolt is well-suited for flywheel, transmission and drive train applications where vibration, high stress and shock cause failure of regular hex head cap screws or bolts. The slots on top with a recessed center creates elasticity so that when it is torqued, the head distorts to maintain clamp load. The place bolt is usually required to be made in the United States with certifications and head marks, as well as Defense Federal Acquisition Regulation Supplement compliant material.

Elgin Fastener Group is committed to delivering specialty fastener solutions for its clients, no matter the bolt or screw involved. Based on decades of experience, EFG can draw on one project after another to produce high-quality, cost-efficient parts. Explore our capabilities and what can be accomplished. If your company has a specialty fastener need, don’t hesitate to contact Elgin today to get the project started.