One man attends to the engines that drive the shop machinery and the “blower.” It is his duty to see that the shafting is kept clean and the bearings well oiled, to watch over the belts and to notify the strappie when one becomes loose or slips off the wheel. Dressed in a suit of blue overalls, and equipped with ladder and oil-can, he remains in constant attendance upon his engines and shafts. He will also be required to keep a watchful eye upon the valves, to regulate the steam to the cylinders, and to maintain a uniform rate of speed for the lathes and drills. Occasionally, if the pressure of steam in the boilers should rise very suddenly--which sometimes happens, as the result of a variable quality of coal and the diversity of heats required by the furnacemen--the engine, in spite of the regulators, will rapidly gain speed and “run away,” as it is called. This may also result from the disconnecting a particular machine engaged on heavy, dragging work, such as the saw, or fan, both of which require great power to drive them at their high rate of speed.
Considerable danger attaches to the running away of an engine, especially where it is provided with a heavy fly-wheel. This, if it is whirled round at an excessive speed, is liable to burst, and the consequences, in a crowded quarter, would be disastrous. The danger of bursting lies in the tremendous throwing-off power generated from the hub of the wheel, about the shaft; as the sections forming the circle of the wheel are brought rapidly over there is a strong tendency for them to be cast off in the same manner as a stone is thrown from a sling. If the wheel is exactly balanced, however, and every part of precisely the same weight, so as to ensure perfectly even running on the shaft, the danger of bursting will be small. Grindstones burst much more commonly than do metal wheels. There is not the same consistency in stone as in iron; moreover, there may be a flaw somewhere that has escaped the eye of the fitter or overseer. Consequently, if the speed of the engine driving the stone should be immoderately increased, it will not be able to withstand the throw-off, and will fly to pieces, inflicting death, or very severe injuries upon all those in the vicinity.