How it began
Arthur James Arnot arrived in Melbourne from Scotland and in 1889, with his colleague William Blanch Brain, patented the electric drill. Both men were based in Melbourne at the time. Their machine was designed for mining work such as drilling rock faces and coal shafts. Two years later, in 1891, Arnot was appointed the first electrical engineer for Melbourne City Council, where he planned much of the city's original street lighting and designed the Spencer Street Power Station.
How it works
The drill was large and not really portable, so it had to be set down in place to cut through coal and rock. Engineers Australia's account, drawing on a Deakin University engineer, notes that an early motor of this kind would probably have had brushes and thrown sparks, a hazard where flammable gases are present. The motor compartment therefore had to be covered as far as possible without overheating. Water could cool the drill bit, but only air could cool the motor.
How it spread
The portable form came later and elsewhere. In 1895 the brothers Wilhelm and Carl Fein of Stuttgart, Germany, were credited with the first portable hand-held electric drill, though it needed two hands. In the 1910s S. Duncan Black and Alonzo Decker developed the pistol-grip hand drill familiar today.
Who pushed back
The design had to work around several hazards of mine use. If the drill was not grounded properly it would give its user an electric shock. Its cable was another danger, since a cable running through a puddle of water in a mine could electrocute workers. Weight was a further problem, because early casings would have been steel and the motors were large and heavy.
Where it stands today
Electric drills are now standard tools for miners, builders, tradespeople and home users. Most modern casings are plastic instead of steel, to cut weight and improve safety. The original patent drawings are held in the collection of the National Archives of Australia.
