Ironbolted

Ironbolted is an adjective used to describe an assembly, joint, or structure secured primarily with iron bolts as the principal fasteners. In timber framing and shipbuilding, an ironbolted connection relies on bolts that pass through the joined members and are secured with nuts, washers, or similar hardware. The term emphasizes the fastening method rather than the design of the members themselves.

Historically, ironbolting developed as ironworking improved and larger wooden structures required stronger joints. Bolt materials evolved from wrought iron to steel during the 19th century, and bolt production shifted from simple hand-forged forms to standardized sizes. Common forms included through-bolts with square or hexagonal heads, sometimes paired with washers to distribute load. In situations where one side could not be accessed, blind or anchor bolts were used.

Types of ironbolted constructions include timber-framed buildings, ship timbers, and certain bridges where bolt connections provide rapid assembly and disassembly or allow for adjustments. In restoration work, ironbolting is often used to preserve historical authenticity while maintaining structural integrity.

Advantages of ironbolted joints include strong load-bearing capacity, ease of disassembly for maintenance, and the ability to join mismatched timbers or components. Disadvantages include vulnerability to corrosion if not protected, the potential for stress concentration around bolt holes, and higher labor requirements compared with some modern fasteners. In contemporary practice, ironbolting is largely supplanted by steel or alloy bolts for new work but remains relevant in restoration, traditional carpentry, and historical engineering documentation.