Hex head bolts include standard hex head cap screws, structural bolts, heavy hex bolts and flange bolts.

Hex cap screws are common threaded fasteners with hexagonal heads, which are six-sided tops without indentations. These screws allow for greater torque than traditional circular screws and are installed or removed with socket wrenches. They do not require a nut for fastening and come in a variety of materials and finishes, such as black oxide, zinc plated, zinc yellow, armor coated, hot dipped galvanized, and chrome coated. Coated screws have varying degrees of corrosion resistance based on the type of environment in which they are installed. Hex head cap screws are designed to secure objects within or against other objects for a non-loosening hold. These screws may be fully or partially threaded. Fully threaded screws match up with a threaded hole all the way to their heads for gripping and anchoring thin surfaces. Partially threaded screws are tougher and have an unthreaded area under their head to allow for more holding strength when force is applied from the side.

Heavy hex head structural bolts have shorter shanks and thread lengths than standard hex bolts. Structural bolts secure steel-to-steel parts and connections. They have hex heads that tighten with ratchets or spanner torque wrenches. These rugged steel bolts come in galvanized, yellow zinc, and black oxide finishes. Standard heavy hex bolts have larger, thicker heads than regular hex bolts and are most often used in high-temperature, high-strength industrial applications. Heavy hex bolts with forged heads are also commonly used as headed anchor bolts. All are designed to be used with hex nuts for a secure fit.

Flange bolts have a circular edge under the head that acts like a washer to distribute loads. Standard, non-serrated flange bolts are also called frame bolts. Flange bolts are used in automobiles to secure outer casings protecting engines and transmissions. In plumbing, they secure pipe ends to ensure strong hold, regardless of materials in the ducts. Serrated flange bolts have teeth that grip surfaces for a tight hold. In electronics, flange bolts hold components together tightly to prevent particles from getting into devices. In hard-to-reach areas, flange bolts help install decks and overhead attachments more easily than regular bolts and washers. Long flange bolts are used to construct oil rigs, energy plants, and ships.