Walk into a modern machine shop, and it’s easy to be overwhelmed at the amount of advanced technology on display. CNC machines relying on computers and g-code to perform advanced cutting operations on 5-axis machines, or Electron Discharge Machines (EDMs) using electricity to cut through metal parts.
Despite all the advanced technology, all of the machining processes on display are rooted in much older principles. The history of the lathe, one of the most significant machine tools, is a good example.
Early lathes: from wood to metal
Machining is the process by which a piece of raw material is cut and shaped into the desired form. Most machine tools rely on subtractive machining, removing material by cutting or grinding. Machine tools, of various kinds, have been in use for centuries or even longer.
The metal lathe is one such machine. Evidence for the earliest lathes comes from Egypt, where metal-spinning involved two people and a rope-wound spindle. Only pictorial evidence survives, leaving a lot of speculation as to how the earliest lathes worked.
In the ensuing centuries, many cultures used variations of metal-spinning, although until the later middle-ages there was no continuous motion on the spindle. This meant that the cutting wasn’t continuous; it would start, stop, and reset as the workpiece turned.
The oldest modern lathes were used for woodworking and probably originated in France in the 1500s. These lathes were continuous-motion, as foot pedals came into use. The lathe machining process became known as “turning.” Turning on a lathe gave some major advantages; the rotation allowed the material to be removed evenly. Early lathes were operated by a foot pedal or hand crank, and a lathe operator could control how much material was removed by increasing or decreasing the speed of rotation.
With a wood lathe, craftsmen could create table legs and other cylindrical shapes far more quickly than they could be carved by hand.
Who invented the metal lathe?
At the beginning of the Industrial Revolution in England, a handful of inventors made discoveries that became foundational to the technological advances that would follow. Henry Maudslay was one of them. Born in 1771, he worked first for a locksmith and then went into business for himself manufacturing ship’s machinery – pulleys and block-and-tackle.
For the next three decades, Maudslay invented a number of machines, as well as taught other notable inventors and engineers of the Victorian era. One of Maudslay’s most significant inventions was the metal lathe.
Lathes had been used to cut metal before; there was nothing fundamentally different between a metal lathe and a wood-turning lathe, other than perhaps the materials used to make it. Before Maudslay, workers turned metal and used freehand tools to shape the workpiece. This worked, but the resulting pieces were uneven.
Around 1800, Maudslay hit on the idea of fixing the cutting tool to sliding rails. By moving the tool smoothly along the length of the lathe, cuts could be made evenly. Maudslay used his invention to standardize the size of screw threads; in turn, that allowed screws to be mass-produced and used interchangeably.
The importance of the metal lathe
The metal lathe didn’t single-handedly start the Industrial Revolution, but it was one of the major contributors to mass-produced, interchangeable parts. The lathe got an even bigger boost when it was coupled with the steam engine, which allowed the large-scale turning of metal parts.
Maudslay’s metal lathe also proved crucial to the growth of other machine tools. His lathe demonstrated that new methods of construction could be combined to produce new tools and use them with new materials.
Metal lathes today
The revolution of the Age of Computers has also transformed the metal lathe. More advanced lathes today are equipped with Computer Numerical Control (CNC) technology. Using a computer language known as G-code, CNC lathes can be pre-programmed to cut an entire series of parts to the exact same dimensions.
Modern lathes still used the same basic principles as Maudslay’s lathe of 200 years ago, and perhaps of lathes that are much older than that. They continue to be one of the most important machine tools in widespread use today.
