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

by Charles T. Porter

About the same time the absurdity of sending into the field a tank of water, a boiler, an engine and the gun, on separate wheels, connected by pipes or belting, which would be ruined by the least damage to anything, began to dawn on the enthusiasts, and the thing was abandoned.

I furnished one of my first governors to Mr. James Horner to regulate a rolling-mill near Boonton, N. J., a sale which is worth recording. This mill was employed in rolling steel pretty high in carbon into rods for making gimlets, and the three-high train had not yet issued from the brain of Mr. Fritz. The rolling was slow work. The resistance brought down the speed of the engine before the governor could act, and they could have only one pass in the rolls at a time. The workmen had to carry the end of the rod around and insert it in the next groove after it had run out of the former one. The rod would be black before it was finished, and often it was difficult to get it finished at all. I do not know of any change that so much impressed me at the time as did that which followed the putting of my governor on this engine. The full speed was kept up, the billets seemed to rush through the rolls, two and even three passes could be in them at the same time, and the rods were still at a dull red heat when finished.

This success induced me to make a raid on Pittsburg. I found there very different conditions. They then rolled nothing but iron, so far as I saw or heard. In the first mill I visited, after I had discussed the subject with one of the proprietors, an old man came up to me and said, “Do you see that chair? I have sat in that chair twenty-four years.” The chair corroborated his story. “I watch the rolls; when a bar enters them, I turn on more steam; when it goes out I shut it off. If you put in a governor that will do as well, I shall be discharged. I don’t know how to do anything else; I have a family dependent on me, and I don’t know what I should do.” I did not hesitate long about what I should do. I could not improve on the old man’s action. He regulated the speed perfectly. The only result of my success would be to beggar him. Superseding hand labor by machinery I did not in this particular case care to be responsible for. I concluded that the Pittsburg way was good enough for them, and took the next train for home.

The first governor I sold was to Mr. William Moller for his sugar-refinery on Vandam Street. The engine to be regulated was an old-fashioned beam-engine. The governor was to be set on a bracket that we had to bolt to the wall, and a pulley some 3 feet or more in diameter had to be made in halves and put on the shaft. To make sure that no mistake would be made, I went down myself to make a gauge of that shaft. I took a ³⁄₈-inch steel rod bent to span the shaft, and made of this an outside gauge with great care. Now this was not what I wanted, but I did not know it. I wanted an inside gauge, representing the diameter of the shaft, and what I did make was useful only to compare the two.

I returned highly satisfied with my work, leaving the real gauge to be made in the shop, where it could not be compared with the shaft. What might reasonably have been expected to happen did happen. In some unaccountable way something happened to my gauge, and when we went to install the governor we found the pulley had been bored ¹⁄₄ inch too small. We had to work hard all night, and got through only just in time for the engine to start at its usual hour in the morning. If I had sent a man who knew his business to make this gauge I should have avoided a lot of trouble, but I should not have learned anything.

In preparing for the establishment of the governor manufacture I visited the works of Geo. S. Lincoln & Co., in Hartford, and saw twist-drills in use, cutting chips instead of scraping. They attracted my attention and I inquired about them, and was told that they made them themselves. They kindly took me into the smith-shop and had one made for me to witness the operation. The smith heated a round bar of steel and swaged channels in it on opposite sides. They had quite a set of top and bottom swages for different-sized channels. He then took another heat on the bar and twisted it by hand, giving a gradually increasing twist, which at the end was quite rapid. An increasing twist was obtained in this way. The drill was held in a vise, so that only the projecting end of it could receive the amount of twist then being imparted. The drill had to be moved in the vise of course a number of times. The channels were smoothed out with files, and when the drill was turned in the lathe sharp cutting edges were developed, which needed only to be backed off by grinding. I took one of these drills home with me to serve as a pattern and equipped my shop with them. They were of the highest use to me. The small ones drilled the holes for the governor joints, and the large ones drilled the counterpoise and the column for the governor spindle. I suppose the twist-drill had its origin in these Hartford works.

I never saw any twist-drills in England except at Mr. Whitworth’s, and these I thought were the funniest things I ever did see. They were twisted by the blacksmith out of square bars and with a uniform quick twist, were left rough, and did not fill the hole, and the ends were flattened out in the form of the common drill to scrape, and not to cut.

When I returned from England in 1868 twist-drills were coming into general use in this country. After 1876 the firm of Smith & Coventry introduced them in England.

At that time almost everything in machine-shops was done in the old-fashioned way, and accuracy depended entirely on the skill of the workman. The tool work left much to be done by the fitter. Interchangeability was unknown, even in screw-threads. For example, when nuts were removed from a cylinder head, pains had always to be taken that each nut was replaced on its own bolt, as no two were exactly of a size. This condition developed a class of very skillful all-round workmen; but my earliest observation showed me that in manufacturing it was important that so far as possible the personal factor should be eliminated. I adopted the rule that in mechanical work there was only one way to insure that anything should always be done right, and that was to make it impossible that it should be done wrong. For example, in my governor gears their true running required that the bore should be absolutely correct, both in position and in direction. I had seen many gears bored. They were held in the jaws of a chuck and trued by marking their projecting side when running with a piece of chalk. It was evident that absolute truth could hardly ever be reached in this way, and the approximation to it depended wholly on the skill and pains of the workman. Besides, much time was lost in setting each wheel. These objections were much aggravated in the case of bevel-gears.

I met these difficulties in this way. In standardizing my governors I found it necessary to make eight sizes, but managed to use only three different pairs of gears. I made a separate chuck for each of these six wheels, the faces of which were turned to fit the top and inner ends of the teeth, the same surfaces to which I had seen the chalk applied. When the castings were received from the foundry the first operation on them was to bed them to their chucks, which were covered with a thin coating of red lead for this purpose. The workman was careful to remove only projecting imperfections without touching the true surfaces of the teeth. After this the gears, being held firmly to their chucks by means of a yoke, were bored rapidly and always with absolute truth. Result: their running was practically noiseless.