In the 1830s, square-headed bolts were superseded by the hex head. The widespread use of hex head nuts and bolts came about due to innovation in engineering and metallurgy. Hex head nuts and bolts and the tools to use them require close tolerances, whilst square heads required less accurate tolerances.

Square-headed bolts were commonly used in early applications. When machinists used cast iron and cruder forms of steel, square bolt heads were easier to make with the tools, metals, and techniques of the time. As machinery became smaller and more compact, however, the hex head evolved to meet the need for more compact bolt heads.

To complement our range of fixtures and fittings, we have sourced a range of vintage-style industrial black oxide square-headed bolts. They are available in a variety of sizes and lengths to suit various applications such as furniture construction, woodworking projects, lighting design, and any general vintage industrial project.

To complement our range of fixtures and fittings, we have sourced a number of vintage-style industrial carriage bolts in a black oxide finish. They are available in a variety of sizes and lengths to suit various applications such as furniture construction, woodworking projects, lighting design, and any vintage industrial project. These square head bolts will create a more authentic appearance to your work. Matching washers and square nuts to suit these bolts are also available.

For those of us who struggle with imperial measurements, we have included metric equivalents next to the sizes, usually in brackets [].

Make installation of your lag bolts, pyramid head door screws, and square head machine bolts easier and safer with our 8-point sockets.

https://littleanvil.com/nuts-bolts-screws/8-point-socket

Currently, we carry a limited range of sizes and a small amount of stock. We will continue to increase our range and stock levels over time. Contact us if you require a specific size not on the list or a larger quantity.