DIN 571 Hex hHad Lag Screws

A DIN 571 Hex head lag screws with manufacturer XiaoGuo is a heavy-duty self-tapping fastener with a hexagonal head, a threaded shank with coarse teeth and a conical tip at the end.The dimensions of the opposite sides of the head are in accordance with the standard specifications. It can be operated with a socket wrench, an open-end wrench or an adjustable wrench.The thread profile is deep and the pitch is wide. It is usually a partial thread, with a section without threads near the head, which is used to fix metal components or heavy equipment onto a wooden substrate.

When in use, it is necessary to drill guide holes on the wood in advance, and then DIN 571 Hex head lag screws the screws in. The mechanical interlocking between the threads and the wood fibers will generate high uplift and shear resistance.The material is usually carbon steel or stainless steel. Carbon steel materials usually require surface treatment.

Structure Presentation

DIN 571 Hex head lag screws are fasteners specifically designed for heavy-duty connections in wood. Their structure consists of three parts: the head, the rod, and the tip. These parts work together to achieve high-strength anchoring.

1.Head structure

The head is a standard hex shape, sized to DIN 571. Its height is roughly 60–70% of the thread diameter. This hex shape lets you put a lot of torque on it without slipping. The bottom of the head is flat, and you should normally use a flat washer with it. That spreads the pressure and keeps the head from getting pulled into the wood.

2.Rod and thread structure

The threads are coarse wood threads, with much wider spacing than regular metric threads. They don’t run all the way to the head – there’s a smooth section near the top, about one‑third to half the screw length. The thread crest is fairly sharp, and the root is rounded. That helps it cut into wood fibers and avoids weak spots. The smooth shank is the same diameter as the thread or just slightly smaller.

3.Tip structure

The tip is cone‑shaped, with an angle of about 30–45 degrees. It’s not super sharp – more like slightly blunt. When you start it into a pre‑drilled hole, the tip guides the DIN 571 Hex head lag screws in straight, so it doesn’t go in crooked. In softwood, the tip can push the fibers aside a bit and help it self‑start. But in hardwood, it mainly just guides – you still need to drill a pilot hole.