Kirkaldy Testing Museum - David Kirkaldy and His Universal Testing Machine

David Kirkaldy and His Universal Testing Machine

Kirkaldy worked at Napier shipworks, but left in 1861 and over the next two and a half years studied existing mechanical testing methods and designed his own testing machine. William Fairbairn had pioneered tensile strength measurement as well as assessing creep and fatigue on large structures as well as small. Entirely at his own expense, Kirkaldy commissioned this machine from the Leeds firm of Greenwood & Batley, closely supervising its production. Aggrieved over the slow rate of manufacture, after fifteen months he had it delivered to London still unfinished, in September 1865.

The testing machine is 47 feet 7 inches long, weighs some 116 tons, and was designed to work horizontally, the load applied by a hydraulic cylinder and ram. The working fluid is water not oil. The load is measured by a weighing system consisting of a number of levers with the final one carrying a jockey weight. When in use the operator lets water into the hydraulic cylinder and as the pressure and hence load on the test piece increases the jockey weight is wound along to balance the hydraulic load. As it is wound it moves over a graduated scale and when the object under test fails the number on this scale is noted and multiplied by the weight to give the failure load. The weight can be varied in increments of 50 pounds using slotted plates on a hanger. On the lower scale this reads up to 150 and up to 1000 pounds can be put onto the hanger. A separate jockey weight system above this one allowed the machine to measure loads of up to 1,000,000 pounds.

The machine is still held in working order at the Kirkaldy Museum in Southwark, although problems can occur with the gasket which seals the single hydraulic cylinder. This machine still uses the original material leather rather than a more modern material. Historically the water supply would have come form the London Hydraulic Power Company but now the museum uses an electric pump. When breaking specimens for visitor demonstrations a load not excceding 20 tons would be used.

He also developed methods for examining the microstructure of metals using optical microscopy. It involved cutting sections, polishing the sections and then etching to reveal different constituents.