Diy power

9 min read

TECHNOLOGY

Discover the science and technology behind the power tools in your toolbox

WORDS SCOTT DUTFIELD

Orbital sanders can spin at speeds of around 14,000 orbits per minute

SMOOTH SPINNING ELECTRIC SANDERS

Putting power behind sandpaper, electric sanders use a motor to rapidly expose a surface with abrasive force. First seen in the early 1900s, electric sanders made short work of stripping furniture paint, rounding metal edges and smoothing surfaces. There are typically two main types of sanders. A belt sander uses a drum wrapped in sandpaper, while an orbital sander requires an abrasive disc, held horizontally on a metal plate for circular sanding.

Although they might appear different, they both rely on the same process of abrasion. When a sanding disc rubs against the surface of another material, such as wood, the hard grains of rock on the surface of the disc penetrate the surface of the wood, producing microscopic grooves as they go. The particles of wood that have been excavated from these grooves fly away and layers of the wood are removed, leaving an even surface behind.

The scale of hardness for sanding discs is measured in grits: finer grits are for tackling softer surfaces or producing a polished finish, while coarse grits are used in grinding down hardwood and metal. Along with producing smooth surfaces, sanders also generate a lot of wood and metal dust. To catch the debris, many sanders are equipped with a vacuum device called an aspirator. While the sander is busy grinding down material, the aspirator draws the dust through a series of holes and deposits it into a bag for storage.

5 TYPES OF ABRASIVE DISCS

1 DIAMOND

Diamonds are bound in robust resin and adhered to abrasive discs that are used to smooth out a variety of materials, such as ceramics, titanium, glass or chrome.

2 SILICON CARBIDE

Made from the natural mineral form of silicon carbonate, which are sharp crystals, it makes quick work of cutting into wood.

3 CERAMIC

Densely packed grains of ceramic minerals are used in sanding discs that tackle hard materials such as stainless steel and aluminium.

4 ZIRCONIA ALUMINA

Made from a combination of aluminium oxide and zirconium dioxide, this self-sharpens every time it’s used.

5 ALUMINIUM OXIDE

Used to smooth the rough surfaces of strong materials such as steel, bronze and hardwood.

DRILLING DEEP

The cordless drills you might find in a typical toolbox today all descend from the portable electric drill, invented in 1917 by Americans S. Duncan Black and Alonzo Decker. However, the first electric corded drills were patented by Australian inventors Arthur James Arnot and William Blanch Brain in 1889. Since then, drills have evolved into all shapes, sizes and strengths.

The mechanism of a p

This article is from...

How It Works Magazine

3 August 2023

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