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Two Hex Fasteners, Two Different Jobs The hex head bolt and the socket head cap screw (SHCS, DIN 912) both have six-sided driving interfaces, but they are engineered for different assembly philosophies: the hex bolt for open, wrench-accessible joints, and the socket screw for compact, counterbored machinery joints. Choosing between them comes down to access, […]

What Is Thread Pitch? Thread pitch is the distance between two adjacent thread crests, measured in millimetres for metric threads. An M12 bolt with a 1.75 mm pitch means one full turn advances the bolt 1.75 mm. Every metric size has a default coarse pitch (what you get when nobody specifies otherwise) and one or

Three Bolt Types, Three Different Jobs Hex bolts, carriage bolts, and lag screws all hold things together — but they differ in how they install, what materials they suit, and how strong the finished joint is. Picking the wrong one means either a joint that works loose, or paying for more bolt than the job

What Each Washer Actually Does Washers look like the simplest component in a bolted joint, but choosing the wrong type — or skipping one where it is needed — is a classic cause of loosened connections and damaged surfaces. There are three families you will meet most often in metric hardware, plus a few specialty

Why Tightening Torque Matters A bolt is a spring. Its job is to stretch slightly and clamp your parts together with a controlled preload — typically 65–75% of the bolt’s proof load. What makes torque tricky is friction: roughly 90% of the torque you apply is consumed by friction under the bolt head and in

What Is a DIN 933 Hex Bolt? DIN 933 is the German standard for fully threaded hex head bolts with metric coarse threads. It is dimensionally equivalent to ISO 4017, so bolts made to either standard are interchangeable in most applications. The defining feature of a DIN 933 bolt is that the thread runs the