Standard gauges and Whitworth thread

What it is

A system of flat reference surfaces, cylindrical gauges and a unified 55° thread profile that made screws from different manufacturers compatible. The first national industrial standard.

Whitworth proposed the thread in 1841 before the Institution of Civil Engineers; his three-plate method for generating flat surfaces dates from around 1830.

What it led to

• Industrial standardisation (British Standards, ISO)
• Interchangeability between firms, not just within one
• Precision engineering as a British export industry
• The metric thread standard as a continental response

Built on

• Screw-cutting lathe with slide rest1797-1800
• Interchangeable parts1785-1801
• Metal planer1817-1820

Made possible

• Whitworth rifle
• Millionth-of-an-inch measuring machine
• Sellers's American thread system (1864)

Links