Boulton & Watt

James Watt and Matthew Boulton form a hugely successful partnership that will last for the next twenty-five years.

John Roebuck, the founder of the celebrated Carron Iron Works and a partner with James Watt in developing the latter's steam engine, had gone bankrupt, and Boulton, who owns the Soho Manufactory works near Birmingham, had acquired his patent rights.

An extension of the patent to 1800 is successfully obtained in 1775.

Through Boulton, Watt finally has access to some of the best iron workers in the world.

The difficulty of the manufacture of a large cylinder with a tightly fitting piston is solved by John Wilkinson, who has developed precision boring techniques for cannon making at Bersham, near Wrexham, North Wales.

Watt had tried unsuccessfully for several years to obtain accurately bored cylinders for his steam engines, and has been forced to use hammered iron, which is out of round and causei leakage past the piston.

In 1774 Wilkinson had invented a boring machine in which the shaft that holds the cutting tool extends through the cylinder and is supported on both ends, unlike the cantilevered borers currently in use.

With this machine he is able to bore the cylinder for Boulton & Watt's first commercial engine, and is given an exclusive contract for the provision of cylinders.

Until this era, advancements in drilling and boring practice had lain only within the application field of gun barrels for firearms and cannon; Wilkinson's achievement is a milestone in the gradual development of boring technology, as its fields of application broaden into engines, pumps, and other industrial uses.

James Watt had demonstrated the first practical steam engine in 1769.

His improvements are fundamental to the changes brought by the Industrial Revolution in both Britain and the world.

The first engines are finally installed and working in commercial enterprises in 1776.

These first engines are used for pumps and produced only reciprocating motion to move the pump rods at the bottom of the shaft.

Orders begin to pour in and for the next five years the Scottish inventor will be very busy installing more engines, mostly in Cornwall for pumping water out of mines.

The Smethwick Engine is to operate for more than a century as the world’s oldest working engine.

John Wilkinson, apprenticed to an ironmonger at Liverpool, had became an ironmonger himself about five years later.

Wilkinson had probably worked with his father in his foundry (which included a blast furnace) at Bersham in Denbighshire, but in the late 1750s he had established, with partners, ironworks at Willey, near Broseley in Shropshire.

He had taken over Bersham Ironworks as well in 1761, and in 1766 established the Bradley works in Bilston parish, near Wolverhampton.

This has become his largest and most successful enterprise, and is the site of extensive experiments in getting raw coal to substitute for coke in the production of cast iron.

At its peak, it includes a number of blast furnaces, a brick works, potteries, glass works, and rolling mills.

The Birmingham Canal is subsequently built near the Bradley works.

Among his products are cannons.

These are difficult to cast as the presence of 'honeycombs' (blow holes) is unacceptable to the Board of Ordnance.

Traditional cannons had been cast with a core, but in 1774 Wilkinson had proposed casting them solid and boring out the core afterwards.

Cannons had long been bored to remove imperfections in the casting, but casting them solid and boring out the core after made them much better cannons.

Wilkinson had also invented and patented in 1775 a new kind of boring machine, that drilled a more precise hole.

Unfortunately for him, his invention was not novel, and his patent was eventually repealed.

Another important product is steam engine cylinders.

Because his cylinders are so accurately bored, he becomes the main supplier of these for Boulton & Watt, and also licenses steam engines from them to assist in his ironworks.

The original Birmingham Canal is extremely successful but there is a problem with supplying sufficient water to the Smethwick Summit.

Matthew Boulton's partner, James Watt, had just patented an improvement to the steam engine involving an external condenser which improved the efficiency (and therefore reduced the amount of coal needed to run it).

Steam engines are constructed at either end of the Smethwick Summit to pump water used in the operation of the locks back to the summit.

The Spon Lane Engine (April 1778) operates from the Wolverhampton side, and another, the Smethwick Engine (June 5, 1779), pumps water from the Birmingham side of the summit.

The first steam engines had been installed in 1776 and were working in commercial enterprises.

These first engines were used to power pumps and produced only reciprocating motion to move the pump rods at the bottom of the shaft.

The design was commercially successful, and for the next five years James Watt had been very busy installing more engines, mostly in Cornwall for pumping water out of mines.

These early engines were not manufactured by Boulton and Watt, but were made by others according to drawings made by Watt, who served in the role of consulting engineer.

The erection of the engine and its shakedown was supervised by Watt, at first, and then by men in the firm's employ.

These were large machines.

The first, for example, had a cylinder with a diameter of some fifty inches and an overall height of about twenty-four feet, and required the construction of a dedicated building to house it.

Boulton and Watt charged an annual payment, equal to one third of the value of the coal saved in comparison to a Newcomen engine performing the same work.

The field of application for the invention is greatly widened when Boulton urges Watt to convert the reciprocating motion of the piston to produce rotational power for grinding, weaving and milling.

Although a crank seems the obvious solution to the conversion, Watt and Boulton are stymied by a patent for this, whose holder, James Pickard, and associates propose to cross-license the external condenser.

Watt adamantly opposes this and they circumvent the patent by their sun and planet gear in 1781.

Over the next six years, Watt makes a number of other improvements and modifications to the steam engine.

A double acting engine, in which the steam acts alternately on the two sides of the piston, is one.

He describes methods for working the steam "expansively" (i.e., using steam at pressures well above atmospheric).

A compound engine, which connects two or more engine, is described.

Two more patents are granted for these in 1781 and 1782.

Numerous other improvements that make for easier manufacture and installation are continually implemented.

One of these includes the use of the steam indicator, which produces an informative plot of the pressure in the cylinder against its volume, which he keeps as a trade secret.

Another important invention, one which Watt is most proud of, is the Parallel motion, which is essential in double-acting engines as it produces the straight line motion required for the cylinder rod and pump, from the connected rocking beam, whose end moves in a circular arc.

This is patented in 1784.

A throttle valve to control the power of the engine, and a centrifugal governor, patented in 1788, to keep it from "running away" are very important.

These improvements taken together produce an engine which is up to five times as efficient in its use of fuel as the Newcomen engine.

Because of the danger of exploding boilers, which are in a very primitive stage of development, and the ongoing issues with leaks, Watt restricts his use of high pressure steam—all of his engines use steam at near atmospheric pressure.