The LD-392 carbon steel carriage bolt series, also known as a coach bolt or timber bolt, is engineered for fastening wood and light metal assemblies where a smooth, finished head and anti-rotation performance are required. Each bolt features a rounded head that sits flush on the surface for a clean appearance and a square neck immediately beneath the head that seats into a matching square hole. Available in diameters from M5 to M16 and lengths from 16 to 150mm, the series is produced to the DIN 603 / ISO 8677 dimensional standard, ensuring consistent head diameter, neck size, and thread pitch for compatibility with standard nuts and washers.

The defining characteristic of the carriage bolt is its square neck, which provides a self-locking anti-rotation mechanism. When the bolt is inserted into a punched or drilled square hole in timber or sheet metal, the square neck grips the surrounding material so the bolt head cannot turn while the nut is tightened on the opposite side. This allows single-sided tightening, which is especially valuable when access to the head is limited or when the head is concealed within a counterbore. The round head distributes clamping load over a wider bearing area than a countersunk fastener, reducing the risk of pulling through softwood.

Manufactured from carbon steel in Grade 4.6 or 4.8, the LD-392 carriage bolt offers reliable general-purpose strength suitable for timber framing, furniture, and light structural applications. The zinc plating, available in white/blue or yellow finishes, provides good corrosion resistance for indoor and covered outdoor environments, with the yellow variant offering marginally greater protection. For exposure to sustained moisture or corrosive atmospheres, a stainless steel option is available. Each bolt is supplied with a matching nut and washer, allowing complete fastening from a single source and simplifying procurement for builders and fabricators.

For wholesale buyers and OEM accounts, the LD-392 series supports a range of customization options. OEM sizes and grades, custom plating, a ribbed neck variant for improved grip in round holes, private-label packaging, and custom retail packaging can all be supplied to meet regional market requirements. With a minimum order quantity of 1000 pieces, mixed orders across sizes and finishes supported, and a production lead time of 7 to 15 days, the series offers importers, builders, and manufacturers a dependable, standards-compliant source of carbon steel carriage bolts at competitive wholesale pricing.