Engineering reminiscences contributed to "Power" and "American machinist"

by Charles T. Porter

I had an order from John W. Hyatt of Newark for a 6×12-inch engine to make 450 revolutions per minute, to drive an attrition mill running at 900 revolutions per minute, in which he pulverized bones to dust for manufacturing artificial ivory. This was the highest number of revolutions per minute that I had ever employed, and perhaps it was the most absolutely silent running engine that I ever made. Not long after its completion I had a call from a young gentleman who introduced himself to me as Harris Tabor. He told me he had invented a steam-engine indicator which he thought would be superior to the Richards indicator, as the pencil movement was very much lighter and would draw a straight vertical line. He said he called in the hope that I might give him an opportunity to test his indicator on a very high-speed engine. I told him I thought I could do just what he wanted. I took him down to Mr. Hyatt’s place where the engine was running with the indicator rig on it which I had been using; he was, of course, greatly pleased with this remarkable opportunity. He took a number of diagrams with his indicator, and they proved to be quite free from the vibrations which were produced by the Richards indicator at the same speed. I gave him a certificate that these diagrams had been taken by his indicator from a Porter-Allen engine at a speed of 450 revolutions per minute. With these he started for Boston to see Mr. Ashcroft. With the result of that interview the engineering world is familiar. To my great regret not one of the diagrams taken at that time has been preserved either by Mr. Tabor, Mr. Ashcroft or myself, an omission that none of us can account for. The Hyatt plant was afterwards, I understood, removed to Albany, N. Y.

I had a singular experience with another 6×12-inch engine which I sold to William A. Sweet, elder brother of Prof. John E. Sweet, for use in his spring manufactory in Syracuse, N. Y. Mr. Sweet had two batteries of boilers set at some distance from each other and at different elevations; these were connected by a pipe which was necessarily inclined. About the middle of the length of this pipe a stop-valve had been introduced, and when this valve was shut the pipe in the upper end of it was, of course, partly filled with water. My engine received its steam from the bottom of this pipe below the stop-valve. The boilers at the lower end were one day overloaded, and while I happened to be present Mr. Sweet himself opened the stop-valve for the purpose of getting an additional supply of steam from the upper battery, but he did not get it. What he did get was a charge of solid water, which brought my engine to an instantaneous stop from a speed of 350 revolutions per minute. I was standing near the engine and saw shooting out from the joint of the back cylinder head a sheet of water, which at the top struck the roof of the building. On examination it was found that the steel key of the fly-wheel had been driven into the wrought-iron shaft almost half an inch and the shaft was bent. The engine suffered no other injury; the bolts of the cylinder head had not been strained to their elastic limit, and the nuts did not require to be tightened. The shaft was straightened, new key-seats were cut for the fly-wheel, and the engine worked as well as ever—a pretty good proof of its general strength.

Harris Tabor

I had a couple of funny experiences arising out of my new way of boring fly-wheels and belt-drums. I sold an engine to Mr. Westinghouse for his original shop in Pittsburg, before the appearance of the Westinghouse engine. They erected it for themselves. I received a telegram from their superintendent, reading: “The hole in your wheel hub is oblong, what shall we do about it?” To which I wired back: “Put the wheel on the shaft and drive in the key.”

Another superintendent discovered the same unaccountably bad piece of work, and did not communicate with me. He did the best he could by centering the shaft in the hole and filling the spaces on each side with thin iron scarfed down on each edge. Then the key would not enter the keyway; so he reduced it until it would. Then the wheel ran an eighth of an inch out of truth. Then he unstopped the vials of his wrath and poured out their contents on my devoted head.

I had an order from Mr. Mathieson, manager of the works of the National Tube Company, at McKeesport, Penn., for two engines, 28 and 32 inches diameter, with 48 inches stroke. The interest of this story centers in the former of these engines, which made 125 revolutions per minute. One day the governor spindle stuck fast in its column, an accident I never knew to happen before or since, whether caused by a tight fit or for want of lubrication I do not know. Of course the engine ran away like mad. Mr. Mathieson and I were in the engine-room; the last I saw of him his coat skirt was nearly horizontal as he rushed through the door. The engineer ran to screw down the starting-valve. I thought that would be too long a process and ran in front of the fly-wheel to unhook the gab. On the instant, however, I feared what might be the possible effect in the cylinder of instantly arresting the motion of the admission valves at an unknown point in the stroke at that speed, and I did not do it. In a few seconds the engineer had the valve closed, and the engine soon slowed down. The fly-wheel, which was 20 feet in diameter, did not burst, and I was confident it would not. I never had an accident to a fly-wheel, but this was the most severe test to which my fly-wheels were ever subjected. I have heard of many accidents to fly-wheels, in which it was evident that they were so carelessly made it seemed as if they were intended to burst on a moderate acceleration of their speed.

This fly-wheel was necessarily made in halves in order to transport it, and the joints were so made as to be as strong as the section of the rim. As the accompanying [drawing] will show, they were held together by two steel loops opened out of the solid and shrunk in. It will be seen that any section of cast iron at this point was equal to the section of the rim, while the steel loops were stronger. The halves of the hub were held together by bolts and steel rings.

I sold an engine for a rubber manufactory in Cleveland, Ohio, and some months after received a letter from the proprietor saying he had been adding to his machinery and the engine would not drive it all and would not give its guaranteed power, and he wanted me to come immediately and see what was the matter with it. On going into the boiler-room I saw that the steam-gauge showed only 55 pounds pressure. I asked the engineer why he carried so little pressure, and he told me that the safety-valve was set to blow off at 60 pounds, which he considered to be all the pressure a boiler ought to carry; that he had been an engineer several years on the Lakes, where 60 pounds was the greatest pressure allowed. I asked the proprietor if he had his boiler insured; he said he had, in the Hartford Boiler Insurance Company. I said I supposed that company had an agent in Cleveland. He said: “Yes, and his office is around the corner on this block, and if you want to see him I presume I can have him here in ten minutes.” Pretty soon he appeared, and I said to him: “I understand you have insured this boiler.”

“Yes.”