James Watt, Instrument Maker

It's amazing how long it took to get even the basics of thermodynamics figured out. You'd think some clockmaker would have made a little brass steam engine by 1600 or so. But no.

Making a big engine with the necessary precision is hard, but a little demo-sized one was within the limits of 17th century clockmaking skill.

I understand that the article's focus is Watt, but this throwaway line is bit disappointing:

> Wilkinson’s cylinders, true to a circle with a variation of less than width of a shilling — about 1/10th of an inch — were sufficiently precise that Watt’s pistons could work without leaking a noticeable amount of steam.

As much as Watt's engines were an improvement over Newcomen's in efficiency, I wouldn't be surprised if the 'Wilkinson-manufactured' engines were as much again a relative improvement by the same amount over the 'pre-Wilkinson' engines of Watt.

* https://en.wikipedia.org/wiki/John_Wilkinson_(industrialist)

There's an entire chapter on the subject in the book The Perfectionists: How Precision Engineers Created the Modern World by Simon Winchester. From a review of the book by James Gleick:

> Watt, meanwhile, had patented his steam engine, a giant machine, tall as a house, at its heart a four-foot-wide cylinder in which blasts of steam forced a piston up and down. His first engines were hugely powerful and yet frustratingly inefficient. They leaked. Steam gushed everywhere. Winchester, a master of detail, lists the ways the inventor tried to plug the gaps between cylinder and piston: rubber, linseed oil-soaked leather, paste of soaked paper and flour, corkboard shims, and half-dried horse dung—until finally John Wilkinson came along. He wanted a Watt engine to power one of his bellows. He saw the problem and had the solution ready-made. He could bore steam-engine cylinders from solid iron just as he had naval cannons, and on a larger scale. He made a massive boring tool of ultrahard iron and, with huge iron rods and iron sleighs and chains and blocks and “searing heat and grinding din,” achieved a cylinder, four feet in diameter, which as Watt later wrote “does not err the thickness of an old shilling at any part.”

> By “an old shilling” he meant a tenth of an inch, which is a reminder that measurement itself—the science and the terminology—was in its infancy. An engineer today would say a tolerance of 0.1 inches.

* https://www.nybooks.com/articles/2018/10/25/precision-accura...

* http://www.simonwinchester.com/precision-praise

* https://www.goodreads.com/book/show/35068671-the-perfectioni...