Introduction Here is a question that stumps most students: how do you machine a square hole? A drill makes round holes. A milling cutter cannot reach into a hole. A grinding wheel cannot produce sharp internal corners. Yet square holes, hexagonal…

Introduction Grinding is supposed to be the precision process. It holds tolerances of five microns and leaves a surface you can see your reflection in. So why does an engine cylinder bore go through another operation after grinding? And why does…

Introduction Imagine a machining process where the tool never touches the workpiece. No cutting force, no vibration, no tool pressure at all and yet it cuts hardened tool steel at 62 HRC as easily as it cuts mild steel. That sounds…

Introduction A copper water pipe in a building and a resistor on a circuit board are joined by processes that look almost identical. Someone heats the parts, touches a metal rod to the joint, and a shiny fillet appears where two…

Introduction Most welding processes have a heat source you can see and roughly understand. An arc is a glowing column of plasma. A gas flame is burning fuel. Friction is two surfaces rubbing. Laser welding is different. The heat source is…

Introduction Count the holes in the room around you. The screws in a door hinge, the ventilation grille on a laptop, the bolt holes in a chair frame, the sockets in a wall plate. Every one of them had to be…

Introduction A cutting tool must be harder than the material it cuts. That rule has governed everything in machining so far, and it creates an obvious problem: what happens when the workpiece is hardened steel, harder than any tool you can…

Introduction Two workshops, two jobs. In the first, a welder is joining a bicycle frame made of thin aluminium tube. In the second, a welder is joining two sections of a bridge girder 40 mm thick, outdoors, in a stiff wind….

Introduction Ask a professional welder which is better, MIG or TIG, and you will get the same answer every time: it depends on what you are welding. That is not evasion. The two processes are close relatives both are arc welding,…

Introduction Strike a welding electrode against a steel plate and something remarkable happens in the gap. Air, normally an excellent insulator, suddenly conducts electricity. A column of glowing ionised gas forms between the electrode and the metal, and within that column…