MATSEC SEC Engineering Technology key terms

A careful process of identifying hazards in a workshop task, judging how likely and how severe any harm could be, and recording the controls needed to reduce that risk to an acceptable level.

Clothing and equipment worn to protect the body, such as safety glasses, gloves, ear defenders and steel-toed boots. PPE is the last line of defence and does not remove the hazard itself.

A physical barrier, interlocked cover or fixed screen that keeps hands and clothing away from rotating or cutting parts. Interlocked guards stop the machine when the guard is opened.

A clearly marked red control, often a large mushroom-head button, that cuts power to a machine quickly when someone is in danger. It must be reset deliberately before the machine can restart.

The maximum load a sling, jack, chain or lifting point is rated to carry safely under normal conditions. It is marked on the equipment and must never be exceeded.

A metal whose main constituent is iron, such as mild steel, cast iron or high-carbon steel. Ferrous metals are magnetic and, except for some stainless steels, will rust when exposed to moisture.

A metal made by melting two or more elements together to obtain better properties than the pure metal. Steel is an alloy of iron and carbon; brass is copper and zinc.

The ability of a material to be stretched or drawn into wire without breaking. A ductile metal such as copper can be bent permanently and will deform noticeably before it fractures.

The ability of a material to be hammered or rolled into thin sheets without cracking. Malleability is useful in presswork and sheet-metal forming.

The maximum pulling stress a material can withstand before it breaks. It is measured in newtons per square millimetre and is found by a tensile test on a standard specimen.

A material's resistance to scratching, indentation or wear. Hardness is often measured with a file test, a Brinell ball or a Rockwell tester and can be changed by heat treatment.

How readily heat travels through a material. Metals such as copper and aluminium conduct heat well, which matters for heat sinks, welding distortion and insulation choices.

A measuring instrument with a fixed main scale and a sliding vernier scale that allows readings to 0.02 mm or 0.05 mm. It measures outside, inside and depth dimensions.

A precision measuring instrument using a calibrated screw to measure small thicknesses and diameters, usually to 0.01 mm. The thimble is read against the barrel scale.

A flat hardened steel scale marked in millimetres, used for measuring and checking straightness and lengths where a precision of about 0.5 mm is adequate.

A tool with a steel blade set at 90 degrees in a stock, used to mark and check right angles and to test whether an edge is square to a face.

A machine tool that rotates a cylindrical workpiece against a single-point cutting tool. It is used for turning, facing, drilling, threading and taper work.

The rate at which the surface of the workpiece moves past the cutting tool, usually given in metres per minute. It depends on the workpiece material and the tool material.

The distance the cutting tool advances per revolution or per minute during machining. Too high a feed overloads the tool; too low a feed rubs and dulls it.

A rotating end-cutting tool with helical flutes that remove chips and carry coolant to the cutting edges. The point angle is normally 118 degrees for general metal drilling.

A joining process in which an electric arc between an electrode and the workpiece melts the metal and the filler to form a weld pool, protected from the air by flux or shielding gas.

A joining process where a filler metal melting above 450 degrees Celsius but below the parent metal is drawn into a close joint by capillary action; the workpiece itself does not melt.

Joining metals with a filler alloy that melts below 450 degrees Celsius, commonly used for electrical connections. The joint is made by wetting and capillary action, not by melting the parts.

Joining parts with a non-metallic substance that sets by chemical reaction, evaporation or cooling. It spreads load over the whole joint and works well with thin or dissimilar materials.

A bolt, screw or nut-and-bolt assembly that clamps parts together by turning a helical thread. Threads are specified by diameter, pitch and length, and may be tightened to a set torque.

A drawing method that shows a three-dimensional object as separate two-dimensional views, projected onto planes at right angles, so shapes and sizes can be read accurately.

A drawing convention in which each view is placed on the side of the object opposite to the direction of viewing. The plan is drawn below the front view and is common in Europe.

A pictorial drawing with three axes at 120 degrees to each other, drawn along lines 30 degrees from the horizontal. True lengths are used along each axis.

A drawing that imagines the object cut by a plane so hidden internal detail can be shown with solid outlines and hatching on the cut surfaces.

A list of every part, material and quantity needed to make a product, usually with part numbers. It is used for costing, ordering and assembly.

The ratio of the number of teeth on a driven gear to the number on the driving gear. It sets the change in speed and torque through a gear pair.

The ratio of the output force a machine produces to the input force applied. A lever or pulley system with a mechanical advantage greater than one multiplies force but needs more movement.

A rotating or sliding shaped part that converts motion, usually rotation, into a controlled follower movement such as lifting and dropping a valve.

A component that supports a rotating shaft and reduces friction between moving parts. Plain bearings use a low-friction lining; ball and roller bearings use rolling elements.

The relationship V = IR: the voltage across a conductor equals the current through it multiplied by its resistance, provided the temperature stays constant.

A circuit in which current has only one path, so the same current flows through every component and the total resistance is the sum of the individual resistances.

A safety device containing a thin wire that melts and breaks the circuit when the current exceeds its rating, protecting wiring and equipment from overheating.

An electrically operated switch in which a coil creates a magnetic field that pulls contacts open or closed, allowing a small control current to switch a larger load.

A written statement of what a product must do and the constraints it must meet, such as size, cost, materials, safety and appearance, used to judge design solutions.

A first working model built to test a design idea, check fit and function, and show users how the product would work before production begins.

A bar chart that shows project tasks along a timeline, making durations, overlaps and deadlines visible so that a project can be planned and monitored.

Energy from sources that are naturally replenished on a human timescale, such as solar, wind, hydro, tidal and biomass. Using it reduces reliance on fossil fuels.

Getting the same useful output from less energy input, for example by using a more efficient motor or better insulation. It lowers running cost and emissions.

A method of adding up the environmental impacts of a product from raw material extraction through manufacture, use and disposal, so that design choices can be compared fairly.