//Reference was made in an earlier article to a paper read before the Institution of Mechanical Engineers in 1893, by Mr. A. Borodin, on the working of steam pumps in Russia.
The author of that paper gives particulars of a test of a small Savery-type pump (of less than one-half actual horse power) showing a steam consumption of 860 lb. per pump or useful horse power per hour, or 2,300 foot-pounds per pound of steam. In the discussion on the paper, one member gave the steam consumption, obtained by a rough calculation from the performance of a Savery-type pump he had employed, as 4,300 foot-pounds per pound of steam, which is equal to 460 lb. of steam per pump horse power per hour. From a test by another member, a steam consumption of 306 lb. per
useful horse power per hour was given by a pump discharging 70,000 gallons per hour. But from the result (also presented during the discussion) of a trial made by Professor T. H. Beare, on behalf of the Pulsometer Company, with a pulsometer fitted with the Grel controlling valve, a consumption of but 148 lb. of steam per horse-power hour was obtained, or 13,415 foot-pounds of work done per pound of steam consumed. The conditions under which the test was made were described as follows: An unlagged vertical boiler standing in an open yard, and an unlagged steam pipe 62 ft. long to the pulsometer; mean boiler pressure 55 lb. per square inch, feed water supplied 361 lb. per hour; measured height of lift 73 ft., or by pressure guage 84.4 ft., including friction. The water pumped was 5,738 gallons per hour, which, against the head of 84.4 ft., represented 2.45 horse power.
The results given above should be compared with the particulars we have previously given concerning the steam consumption of pumps of the boiler-feed type. It will be found that the pulsometer working expansively, as described, compares very favourably with many of such pumps.//
расход пара получается около 60-70 кг на лс в час, то есть угля (при кпд бойлера около 60%) 6-7 кг. В комбинации с водяным колесом получается вполне приемлемый универсальный двигатель с эффективностью точно не хуже, чем хорошая машина Ньюкомена. Для откачки шахт, правда, не очень годится.

>>Ватт был новичком, спецы работавшие над паровиками уже больше половины столетия секретами с ним не делились. Имхо это прекрасно объясняет почему ему требовалась точность повыше чем та что прекрасно использовалась и до него.>>

//He allowed Watt to run and test a Newcomen engine in one of his coal mines, probably not that at the Schoolyard Pit.  The cylinder diameter of that engine was 5ft 3ins (and it is now in Kinneil Park), but that tested was smaller with a cylinder of 32ins and stroke of 5ft 2ins.  Watt calculated the evaporation rate of the boiler, the volume of the cylinder and the surface area of the piston.  He determined how much steam was condensed in warming the cylinder before each stroke and found it was 97.2 ‘solid feet’ while the cylinder only contained 28.6 ‘solid feet.’   This confirmed just how much steam was wasted reheating the cylinder.  The pressure on the piston was 8.5psi.  This was the first of many trials on Newcomen engines which Watt would conduct and it may have helped him to convince Roebuck of the correctness of his theories because “it served to show the great waste of fuel and steam.”
Watt developed a great understanding of the Newcomen engines at Bo’ness and suggested improvements.  The expertise was not wasted and at some stage in 1765 he went into partnership with Robert Mackell, a millwright and engineer in Falkirk, to build Newcomen engines for other customers.  He needed the money to look after his family and to fund further work on his new design of engine.  The first of the engines produced by the partnership was a small engine to pump water to a turpentine still-tub at Carron Wharf near Carronshore, which was completed by the end of the year.  The parts must have been made by Carron Company and Watt was to become familiar with the works there.
…
Watt needed practical experience on existing steam engines and continued his partnership with Robert Mackell.  In this period they erected:

1765 – a small engine to pump water to a turpentine still-tub at Carron Wharf near Carronshore

1766 – an engine with a 24ins cylinder for Bruce at Kennet.

1767 – 45ins cylinder at Newton of Ayr.

1768 – Engines with 18ins & 20ins cylinders for Colville at Torryburn.//

Ватт, к которому идея об отдельном конденсаторе пришла в 1765 г, и который к этому моменту уже лет пять экспериментировал с паровыми двигателями, в промежутке 1765-1770 занимался строительством обычных ньюкоменовских машин на заказ. После получения патента в 1769 и вступления в партерство сначала с Робуком, а затем с Болтоном, Ватт занимался только попытками построить конденсаторную машину, а от заказов на постройку обычных машин отказывался. Тот же Смитон, например, построил свою первую паровую машину также в 1765, а первый заказ на строительство паровой машины получил в 1767.

The Machine in America. A Social History of Technology, Carroll Pursell · 2007
//Another example can be taken from the extremely important field of machine tools. To be most useful, iron had to be worked into useful shapes. The only machines that could possibly accomplish this were themselves made of iron. Thus each improvement in metallurgy made it easier to cut and work iron, and this in turn made it possible to produce more and better iron products. Here, too, Wilkinson was a pioneer innovator. Until his time, metal had to be bored by cutters attached to a turning rod extending from the shaft of a waterwheel to the workpiece. On large jobs, the head tended to droop and thus bore a crooked cylinder. When James Watt developed his steam engine, several people, including Smeaton, advised him that although workable in theory (and in small models with cylinders of tin hammered into shape around a wooden core), it could never be machined with sufficient accuracy to work well in full scale and under industrial conditions.
In 1775, however, Wilkinson built his celebrated boring mill, which allowed him to bore all of Boulton and Watt’s cylinders with considerable accuracy. To gain this new accuracy, he fixed the hollow-cast cylinder more firmly while it was being bored, and more important, he ran the boring rod through the entire cylinder so that the cutting blades could be placed in the middle of the rod and both ends could be supported, so as to eliminate the droop. In 1776 Matthew Boulton wrote with delight that «Wilkinson hath bored us several cylinders almost without Error; that of 50 inches diamr for Bentley & Co. doth not err the thickness of an old shilling in no part.»//

The Makers of the Modern World from Gutenberg to Gates, 2 Volumes. John W. Klooster · 2009
//Watt, having heard of Wilkinson’s achievement, asked Wilkinson if Wilkinson could use his new technology to make a cylinder and piston for Watt’s engine, which Wilkinson proceeded to do. In 1775, within a few weeks after getting Wilkinson’s turned iron cylinder and mating piston components, Watt and Boulton had an improved (relative to the prototype), successfully operating new steam engine. It used less than half as much fuel as that required by a Newcomen engine for producing the same amount of work. Wilkinson’s boring technology seems to have achieved a maximum error (deviation from circular) of only about the thickness of a shilling. Without such accuracy, the Watt engine would not have achieved the efficiency of operation needed for widespread commercial use and success (which was attained).//

Winterstoke. L.T.C. Rolt · 2015
//Because Watt’s design demanded much greater accuracy in construction and finish, for some years the inventor had been frustrated by a manufacturing technique unable to fulfil the demands he made upon it. One of the greatest difficulties was the machining of his cylinders. The old Newcomen cylinders had been bored at Darley Bank by means of a rotating boring bar which produced a bore that was perfectly circular but seldom truly parallel throughout its length. It was the great ironmaster, John Wilkinson of Berstham, who first succeeded in producing a machine capable of boring a cylinder to satisfy Watt’s more exacting standards. It was upon such a machine, whereon the cylinder revolved about a stationary boring bar, that the cylinders for these Watt engines were finished at Darley Bank.//

Fundamentals of Metal Machining and Machine Tools, Third Edition. Geoffrey Boothroyd, Winston Anthony Knight · 1989
//In 1776 James Watt built the first successful steam engine, and one of his greatest difficulties in developing this machine was the boring of the cylinder casting. His first cylinder was manufactured from sheet metal, but it could not be made steamtight. Even attempts to fill the gap between the piston and the cylinder with cloth, leather, or tallow were of no avail. The problem was eventually solved by John Wilkinson when he invented the horizontal-boring machine. This machine consisted of a cutting tool mounted on a boring bar that was supported on bearings outside the cylinder. The boring bar could be rotated and fed through the cylinder, thus generating, with the tool points, a cylindrical surface independent of the irregularities of the rough casting (Fig. 1.1). This boring machine was the first effective machine tool, and it enabled James Watt to produce a successful steam engine.//

Steamboat Evolution. Basil Clark · 2007
//Accuracy in boring cylinders was always a problem, with irregularities resulting in power loss and in 1765 Smeaton made improvements to a boring machine used by the Carron Ironworks in Scotland., this resulted in some improvement but hand finishing was nearly always necessary There is an interesting description of similar work in America in 1801, which given that technology in America at that time was said to be some fifty years behind that in England, is probably representative of the situation there in the 1760’s. The task involved a large iron cylinder which had been cast in two pieces, united by copper and the whole assembly secured by external iron bands. The resulting cylinder was a little over 6ft long and had a bore of about 38 ins, the weight of iron was said to be 7,500lbs, and about 4in had to be cut away internally. The report then states that ‘two men are required; one almost lives in the cylinder, with hammer in hand to keep things in order and attend the steelings; the other attends the frame on which the cylinder rests, which is moved by suitable machinery; these hands are relieved. The work goes on day and night. One man is also employed to grind the steelings; work stands only at dinner and whilst the steelings are being changed, which requires about ten minutes time, and in about ten minutes more are dull. I examined the same and found them worn sin in that time. Three steelings, which are about 3/2 in on the edge are fixed in the head piece at one time; the head piece is a little less than the diameter, which forms the shaft of the water wheel. The workmen state that the boring was commenced on the 9th April and has been going on ever since, about three months, and that about six weeks more will be required to finish it. When the cylinder was completed it is recorded that it was 3/8 in larger in diameter at the mid point of its length than it was at the ends. The method described was very similar to that used in Smeaton’s boring machine and although this machine had improved accuracy the standard produced did not satisfy James Watt when he was building his first steam engine near the Carron Works, this engine took seven years to develop and in the course of its construction Watt tried and discarded a number of cylinders of different sizes and materials.//

Metal Cutting Theory and Practice. David A. Stephenson, John S. Agapiou · 2018
//The bores of atmospheric steam engines invented in the early eighteenth century, which were used especially to pump water from mines, were machined on modified canon boring mills [39,59,60,67]. These mills were not suitable, however, for the manufacture of James Watt’s condensing engine, which operated at higher pressures and consequently required more precise bores. In fact, Watt, an instrument maker by trade, made small model engines but could not produce a full-sized specimen for 10 years because existing boring mills could not machine large cylinders to the required accuracy 164,671. This problem was solved when John Wilkinson invented a more accurate horizontal boring mill in 1775 (Figure 1.8) [31,59,60,64]//

Illinois Technograph Том 45, 1930
//The introduction of the Newcomen and Watt engines with cylinders 30 to 60 inches in diameter created new and difficult problems. Smeaton had designed a boring machine in 1769 for machining cannon. This machine is shown in Fig. 4, as applied to the boring of a cylinder. It consisted of a head with inserted cutters mounted on a long, light, overhung boring bar, driven by a water wheel. The work was mounted on a rude carriage and fed forward against the cutter by means of a hand windlass. The cutter head was supported upon a small carriage running in the cylinder, but this merely reproduced the irregularities in the original casting and the finished cylinder was neither straight, nor true in circumference. When Watt conceived the idea of the separate condenser in 1765, he was beset with seemingly insurmountable difficulties as regards mechanical equipment for building his engine on a commercial basis. «He was a skilled instrument maker and his first small model was fairly successful, but when he undertook the practice of mechanics in the great his skill and the skill of all those about him was incapable of boring satisfactorily a cylinder six inches in diameter and two feet long: and he had finally to resort to one which was hammered. For ten weary years he struggled to realize his plans in a full-sized engine, unable to find either the workmen or the tools which could make it a commercial success. His chief difficulty lay in keeping the piston tight. He wrapped it around with cork, ailed rags, tow, old hats. paper and other things, but still there were open spaces left, sufficient to let the air in and the steam out. Small wonder, for we find him complaining that in an 18-inch diameter cylinder, at the worst place the long diameter exceeded the short by three-eights of an inch. When Smeaton first saw the engine, he reported to the Society of Engineers that neither the tools nor the workmen. existed that could manufacture so complex a machine with sufficient precision.»//

Roe. English and American Tool Builders
//In 1774 Wilkinson made improvements in the boring machine that can hardly be overestimated in their importance. He made the boring bar heavier, ran it clear through the cylinder giving it a fixed support on the outer end. The significance of this improvement may be judged by the statement of a member of the firm of Boulton and Watt who wrote that Mr. Wilkinson had bored for them a cylinder 50 inches in diameter which did not err «the thickness of an old shilling in any part,» a remarkable accuracy for the boring equipment of that period. It made the steam engine a success, and it may be considered as the first machine tool that was adequate for the requirements of large heavy work//

//James Watt was a maker of mathematical instruments, a man of great skill and precision as a craftsman, but he dealt with parts of small dimensions. When he conceived of his steam engine, he mentally pictured the various parts as turned out with all the accuracy and finish that was possible in the diminutive members of a scientific instrument. To him it seemed perfectly feasible to turn a cylinder which would be practically perfect in contour, and to fit it with a piston around which no steam could leak. With the lathe then in existence such a fit was easily possible on small work. But when he undertook to have the cylinder of his engine bored, he discovered that there was no machine that could begin to do the work properly. In fact, when Smeaton, who was a prominent engineer of that time, investigated Watt’s steam engine, he declared that it was such a complicated piece of work that neither tools nor workmen existed that could build it. In Watt’s first engine, the cylinder was only six inches in diameter and two feet long, and a special type of boring machine was devised to bore the forged cylinders. But the boring was so irregular that when the piston was inserted and the steam was turned on, nothing would stop the flow of steam that leaked around the piston. In vain did James Watt use cork, oiled rags, tow, paper, and even old hats to stop the leakage. However, the boring machine was improved and later a cylinder, eighteen inches in diameter, was bored with such accuracy that the large diameter exceeded the small diameter in the worst place by only 3/8 of an inch. This Watt considered a very good bit of turning//

A Short History of Technology from the Earliest Times to A.D. 1900. Thomas Kingston Derry, Trevor Illtyd Williams · 1960
//On the constructional side the greatest difficulty, already alluded to, was in boring a really accurate cylinder, so that there would be no escape of steam between its walls and the piston. Newcomen’s device of sealing the piston with cold water did not suit Watt’s purpose, which was to keep the cylinder as hot as possible. The extent of the constructional difficulty is indicated by the fact that Smeaton, as experienced and progressive as any engineer of his day, gave his considered opinion that ‘neither tools nor workmen existed that could manufacture so complex a machine with sufficient precision’. Millwrights were at that time the only class of workmen approximating to skilled engineers, and engine-building had to be undertaken by the combined efforts of blacksmiths, wheelwrights, and car- penters. When the time came to build Watt’s engines, they were normally constructed of local materials with local labour; Watt sup- plied merely the drawings, an erector for the job, and special parts like valves. A decisive advance was John Wilkinson’s invention of a new type of boring-mill in 1774 (p. 350), designed for cannon but capable with modifications of boring cylinders to fine limits for any purpose.//

Rolt. Tools for job
//Watt only called for an 18-inch cylinder a modest enough demand when we recall the huge Newcomen type cylinders which had been produced by this date yet Smeaton’s boring mill at Carron failed to achieve a sufficiently accurate result and Watt eventually abandoned his fruitless efforts to make his piston steam tight.//

Poverty and Progress. An Ecological Model of Economic Development. Richard G. Wilkinson · 2022
//Steam power was first used in response to the pumping problem in mines as coal production was expanded, and was later used to help meet the growing demand for transport. The early engines had to be designed so that they could be built in an alien technological context. So severe were the productive constraints that it was only just possible to produce a workable engine of any kind. Newcomen’s engine, which used leather packing and water to make a seal between the piston and the cylinder, was extremely inefficient. When Smeaton saw Watt’s improved design he believed that ‘neither tools nor workmen existed that could manufacture so complex a machine with sufficient precision’.1 Smeaton had been involved earlier in the development of better cylinder-boring machines, and his judgement proved correct to the extent that Watt’s engine was only built with the help of a modified version of a new machine for boring cannon.//

//He was a skilled instrument maker and his first small model was fairly successful, but when he undertook «the practice of mechanics in great,» his skill and all the skill of those about him was incapable of boring satisfactorily a cylinder 6 inches in diameter and 2 feet long; and he had finally to resort to one which was hammered. For ten weary years he struggled to realize his plans in a full-sized engine, unable to find either the workmen or the tools which could make it a commercial success. His chief difficulty lay in keeping the piston tight. He «wrapped it around with cork, oiled rags, tow, old hats, paper, and other things, but still there were open spaces left, sufficient to let the air in and the steam out.»» Small wonder! for we find him complaining that in an 18-inch diameter cylinder, «at the worst place the long diameter exceeded the short by three-eighths of an inch.» When Smeaton first saw the engine he reported to the Society of Engineers that «neither the tools nor the workmen existed that could manufacture so complex a machine with sufficient precision.»»»

Smeaton himself had designed a boring machine in 1769 for the Carron Iron Works for machining cannon, an illustration of which is given in Fig. 1. It consisted of a head with inserted cutters mounted on a long, light, overhung boring bar. The work was forced forward on a rude carriage, as shown. The method of supporting the cutter head, indicated in the section, shows an ingenious attempt to obtain a movable support from an inaccurate surface. One need hardly say that the work resulting was inaccurate. Fortunately, in 1774, John Wilkinson, of Bersham, hit upon the idea, which had escaped both Smeaton and Watt, of making the boring bar heavier, running it clear through the cylinder and giving it a fixed support at the outboard end as shown in Fig. 7. The superiority of this arrangement was at once manifest, and in 1776 Boulton wrote that «Mr. Wilkinson has bored us several cylinders almost without error; that of 50 inches diam- eter, which we have put up at Tipton, does not err the thickness of an old shilling in any part.»» For a number of years, Wilkinson cast and bored all the cylinders for Boulton & Watt.
The importance to Boulton & Watt of the timely aid of Wilkinson’s boring machine can hardly be overestimated. It made the steam engine a commercial success, and was probably the first metal-working tool capable of doing large, heavy work with anything like present-day accuracy.»//

Дак и сам Ньюкомен, очевидно, не с полноразмерного двигателя начинал, а с моделей поменьше. Информации про него немного, но пишут, что лет десять эксперементировал перед постройкой машины.
И Ватт именно на маленькой модели своего двигателя показал эффективность конденсатора, и вообще раньше Смитона начал с паром работать.

Модель колеса «подливной» конструкции Джона Смитона. Колесо диаметром два фута. Из «Экспериментального исследования», 1760
…
Что же мешало выполнить эксперименты Смитона в 1680-х или даже в 1580-х гг.?[306] Работа Смитона зависела от двух интеллектуальных предпосылок. Во-первых, все знали, что работа с масштабными моделями может вводить в заблуждение, поскольку механизмы нормального размера часто ведут себя иначе. Понятийный аппарат для анализа этой проблемы предоставил Галилей в своем труде «Две новые науки», и Смитон принял во внимание один аспект, тот факт, что в масштабных моделях трение обычно больше, чем в механизмах нормального размера, – он искусно измерил величину трения в своих моделях, а затем учел ее. Во-вторых, работа Смитона опиралась на систематическое применение закона Торричелли. К этим двум предпосылкам можно добавить и третью: при вычислении эффективности водяного колеса путем сравнения работы на входе и на выходе Смитон пользовался законом сохранения энергии Ньютона. В этом смысле его работа была постньютоновской.
…
Дезагюлье изготавливал модели паровых машин в 1720-е гг., причем он был явно не первым.
Desaguliers
models https://sci-hub.tw/https://www.jstor.org/stable/10.1086/235069

//On the other hand, the capability to machine workpieces of a limited size was widespread by 1820.8 This circumstance may, in part, have influenced the choice between high- and low-pressure steam engines.
The largest machined surface of a steam engine is the cylinder bore. For a 24 horsepower high-pressure engine, the cylinder was 9 inches in diameter by 40 inches in length and probably weighed about 1,000 pounds. A workpiece of these dimensions would have been well within the capacity of most general machine shops in 1820. The cylinder for a 24 horsepower low-pressure engine would have been 26 inches in diameter, 5 feet long, and weighed about 4,000 pounds. It is unlikely that there was a machine shop capable of handling such a casting outside of New York or Philadelphia prior to 1825. Oliver Evans’s well- equipped Mars Works, which built the 20-inch diameter pumps for the Philadelphia Fairmount water works in 1815, was capable of boring only to a maximum diameter of 10 inches.9//

Прибор для опрессовки котлов. Манометр, очевидно, можно заменить грузом, подвешиваемым на конец рукоятки.
https://dl.dropboxusercontent.com/s/jw6yt6d0pemf4sb/boiler%20prover.png?dl=0

//»Watt says, in 1761 or 1762:-‘I made some experiments on the force of steam in a Pepin’s digester, and formed a species of steam-engine. But I soon relinquished the idea of constructing an engine upon this principle, from being sensible it would be liable to some of the objections against Savery’s engine; from the danger of bursting the boiler, and the difficulty of making the joints tight, and also that a great part of the power of the steam would be lost, because no vacuum was formed to assist the descent of the piston.’//
Патент Ватта 1769
//Fourthly, I intend, in many cases, to employ the expansive force of steam to press on the pistons, or whatever may be used instead of them, in the same manner as the pressure of the atmosphere is now employed in common fire-engines. In cases where cold water cannot be had in plenty, the engines may be wrought by the force of steam only, by discharging the steam into the open air after it has done its office.//

Очень характерный показатель возможностей механической обработки в XVIII в — это артиллерия. Если для пушек начала века обычным считался зазор между каналом и ядром в 2-3 линии (5-8 мм), то с усовершенствованием технологии сверления в середине века зазор уменьшили до одной линии, т.е. 2.5 мм. Очевидно, точность обработки была как минимум на порядок лучше, а фактические значения диаметра ствола и ядер указывались до точек (1/100 дюйма, 0.25 мм).
В Англии усовершенствования в области сверления были внедрены несколько позже, чем во Франции, но как раз на Карронском заводе около 1770 г начали производить знаменитые карронады, улучшенное качество обработки канала в которых позволило использовать сильно уменьшенный заряд.
Однако обработка больших по размеру изделий по прежнему оставалась крайне сложной задачей. Смитон построил свой станок, на котором стало возможным растачивать очень большие цилиндры, на том же Карронском заводе в 1770 г, но не смог кардинально улучшить ситуацию с точностью. Станок Вилкинсона, появившийся в 1774 г, смог обеспечивать точность обработки 1-2 мм.

Хотя изготовление насоса для проведения гидравлических испытаний не вызовет сложностей даже в античном мире, можно обойтись даже без него, используя так называемый гидравлический парадокс, известный, вероятно, каждому по знаменитому опыту Паскаля с бочкой.
http://elkin52.narod.ru/biograf/paskal.jpg