This engine afforded me a curious experience. When it was started, teeth were broken out of the gear at the very first revolution, and I received a telegram from them telling me of this misfortune and that I must come to St. Louis immediately and see what was the trouble with the engine. I was too busy to go myself, but Mr. Phillips kindly permitted his engineer, Mr. Collins, to go in my place. Mr. Collins took with him everything necessary to expose the defect, whatever it might be, which we expected would be found in the gearing. Among other things he had the pattern-maker prepare for him two or three short pieces of lath about two inches wide and one eighth of an inch thick; these latter proved to be all that he needed. On his arrival the proprietors assured him there could be no fault with the gearing, for they had it made by the most eminent engineering firm in St. Louis. The members of this firm showed him triumphantly the broken pieces and directed his attention to the perfect soundness of the metal, as proved by the fractured surfaces. His first experiment was to whittle an end of one piece of lath to fit exactly between two teeth of a wheel at one end of the space. To his amazement he found that this templet would not fit in any other space around the whole wheel, every one was in some degree or other too large or too small; neither would the templet fit in the opposite end of the same space. This one experiment settled the matter; the engine, to be sure, had broken the gears, because the larger teeth of the driving-wheels had wedged into the smaller spaces of the driven wheels. How such work could be produced was a puzzle to Mr. Collins; as for myself, I have never wondered at any imperfection in gearing since my experience with Mr. Whitworth’s work. The owners of the rolling mill applied for advice to Samuel T. Wellman, the manager of the Otis Steel Works at Cleveland. He gave them the sensible advice to abandon altogether the plan of driving through gearing, and to drive each train by a separate engine, directly connected, which my high-speed engine would enable them to do. This was the first I heard of Mr. Wellman, with whom I was afterwards to have such pleasant relations.
While on the subject of gearing I will state a couple of incidents. One of my first small engines I sold to Mr. Albright of Newark, a harness-maker. Half of the power of the engine was to be transmitted to an adjoining building driving a vertical shaft through a pair of miter gears. It was required that these should run noiselessly, which at 350 revolutions per minute seemed a difficult thing to accomplish. I had the gears cut in the best gear cutter I knew of, and fitted them to run in a lathe, the spindle of the driven gear running in a frame made for the purpose, and being provided with a friction wheel and brake. To make sure that the same teeth and spaces should always come together, I made a prick-punch mark on one tooth and behind the corresponding space. When started at 350 revolutions they rattled finely. The resistance of the friction brake was sufficient to make the points of contact on the teeth mark themselves well in 15 minutes’ running. I then took them down and carefully removed the bright spots on the surface with a scraper. The next time the noise was more than half gone, and four successive scrapings by a skillful workman cured it entirely. There is this encouragement in correcting gearing, that its subsequent running always tends to improve the truth of the surfaces; they wear to a more general contact.
One day I had a letter from Mr. Barclay, the miller for whom I had made my first engine in Harlem, and which I arranged to drive his millstones by belting. He told me he had moved his mill from Harrison Street to a building on North Moore Street, New York, and he found there was something the matter with the engine. (In these cases there is always something the matter with the engine.) It used to drive three runs of stones, now it would only drive two, and he burned a great deal more coal than before. He wanted me to come and see what the matter was. The moment I opened the door of his mill I knew what the matter was. I heard the roar of rough gearing and was pretty mad. I told him I hoped he liked that music, for it cost him more than half the coal he was burning to keep it up. I gave him a sharp piece of my mind for changing the system of driving from that which I had provided without consulting me on the subject. I told him when he threw out his gearing and put the pulleys and belts back just as I made them, he would find the engine would give him the same power that it had done for five or six years in its old location.
Robert W. Hunt
In the first engines which I built in Newark the governor had a more or less uncomfortable action. This annoyed me exceedingly. It did not sensibly affect the running of the engine, but was a drawback to the appearance of the engine in motion. I was utterly at a loss how to account for it, so I finally determined I would solve the problem by a comparison of two engines of the same size. One of these was the smaller engine for the rolling mill at Troy, where the action of the governor was quite satisfactory; the other was an engine I had made for the Newark Lime and Cement Company, in which the action of the governor was very unsatisfactory. After some weeks of comparison I gave the problem up: I could get no light on the subject. Soon after I had occasion to go to Troy and found my smaller engine running at double its former speed or at 224 revolutions per minute. Mr. Robert W. Hunt, the general superintendent, informed me that they planned to employ this speed when rolling steel to finish at very small sizes, which they were then doing for the first time. The action of the governor which had before been so perfect was now most abominable; the counterpoise flying up and down furiously between the extreme points of its action. I told Mr. Hunt that something was hindering the action of the governor, and asked him if he would have an examination made and let me know what he found. A few days after I received a letter from him saying he had found nothing at all, but he added that that order had been completed and the engine was running at its old speed, and the governor was working as well as ever. In an instant the truth flashed upon me; it was the inertia of those polished cast-iron disks on the rocker-shaft which I had thought so much of that caused all the trouble. This inertia, increasing as the square of the speed, had offered four times the resistance to the reversing of their motion when the speed of the engine was doubled, and the pressure of the link which was necessary to overcome this resistance held the block fast. The governor could not move it until it had accumulated sufficient force by change of its speed; then it moved it too far, and so it was kept in constant violent motion from one end to the other of its range of action. I was thoroughly ashamed of myself that when I had made the subject of inertia a study for years this action should have been going on so long, the most prominent thing before my eyes, and I never saw it. I had use enough at once for my new insight as will appear.
The Gautier steel works, which had been located in Jersey City, were removing to Johnstown, Penn., having formed an alliance with the Cambria Iron and Steel Company. Mr. Stephen W. Baldwin, then manager of the Gautier Company, had given me an order for an engine suitable for driving at 230 revolutions per minute their ten-inch train, or it may have been an eight-inch. I went to Jersey City and made a careful measurement of the indicated power required to drive this train. The engine used was rather a large one, with a large and heavy fly-wheel running at slow speed and driving the train at this rapid speed by means of a belt. I found that my 10-inch by 20-inch engine directly connected with the train would, at 230 revolutions per minute, be capable of furnishing twice the power they were then using. I built an engine of that size with a fly-wheel about 8 feet in diameter, shipped it to Johnstown, and sent George Garraty, my most trusty erecter, to set it up. I should say that Mr. Baldwin had meantime severed his connection with the Gautier Steel Company, and it was then in the hands of parties who were strangers to my engines. I received a letter from Garraty stating that on his arrival he had found them just about to send the engine back; everybody about the works had agreed that a man who sent that little engine to drive that train to roll steel was a fool. At his solicitation they promised to do nothing until they should hear from me. I then wrote to the president, Mr. Douglas, stating I had carefully measured the utmost power which that train had required at Jersey City, and had furnished an engine capable of supplying double that power with ease, and I was sure he would run no risk in setting it up. This he consented to do. While Garraty was erecting the engine they were making preparations in the mill to stall it if possible. There was great excitement when it was started; the furnace men worked like beavers and succeeded in feeding billets to the train twice as rapidly as ever before, but they could not bring down its speed in the least. Finally they lowered the steam pressure, but the engine did not stop until they had brought this down to 40 pounds. Then a great shout went up, not for themselves but for the engine, which had shown itself capable of doubling the output of that train, and telegrams were hurried off to the stockholders of the concern in New York and Philadelphia to relieve their anxiety. Garraty left that night and reported himself to me the following morning. After giving an account of the success of the engine he added: “But the governor is working very badly; they have not noticed it yet as they have thought only of the running of the train, but they will.” By a remarkable coincidence I had that very morning received the letter from Mr. Hunt which had opened my eyes to the cause of this bad action; the day before I could not have understood it.
Stephen W. Baldwin
Within twenty-four hours after my interview with Garraty I had started for Johnstown, carrying with me two light steel levers to replace those disks. In that time I had made the drawings and had the levers forged and finished, joint-pins set and keyways cut, perfect duplicates of the disks in all their working features. When I told my purpose to Mr. Douglas he smiled and said for the life of him he could not see what disks on the rocker-shaft had to do with the governor action. However, they had not yet started their night shift, so I might have the engine after 6 o’clock, but it must be ready for use at 6 o’clock the next morning. I told him that as the change would probably occupy me less than an hour, I thought I might safely assure him on that point. I engaged a machinist with the engineer to help me at 7 o’clock in the evening and amused myself the rest of the day about the mill. The furious governor action was so irritating I did not stay long in the engine-room. In the evening we had the disks off and the levers on and all connected up, ran the engine idle for a few minutes to see that all was right and I was back in my hotel within the hour, which illustrated the advantage of working to gauges. I had taken off 29 pounds weight, that being the difference between the weight of the disks and the levers. Next morning I went down to see the effect of this change. It seemed magical. The governor appeared to have gone to sleep, it was not taking any interest in the activity about it; the counterpoise stood at about the middle of its range of action, only moving lazily a short distance up or down occasionally. After calling Mr. Douglas in to see what disks on the rocker-shaft, with their motion reversed 460 times a minute, had to do with the governor action, and hearing his expressions of admiration, I took the next train home. As might be supposed I was not long in eliminating all traces of this blunder from drawings and from engines already made.