Square Neck Bolts are also known as square neck carriage bolts. Square neck bolts are most commonly used in wood. They generally have a square or domed top and a square base under the head. This square base pulls into the wood as the nut is tightened for a secure fit. Square neck bolts are available in a variety of diameters, and are made from broad number of grades and types of steel. This wide selection of materials and sizes makes square neck bolts an excellent choice for any application. Some common types include:

• Zinc-plated square neck bolts: offering moderate protection against rust
• Steel grade 5 square neck bolts: steel alloy with high corrosion resistance; the material of choice for exterior and marine applications
• Silicone bronze square neck bolts: copper alloy with better strength and corrosion resistance than brass; used in wooden boat building
• Hot dipped galvanized square neck bolts: much greater corrosion resistance than zinc-plated; galvanized butts for use in coastal areas