Rough and Tumble Engineering by James H. Maggard
page 58 of 122 (47%)
page 58 of 122 (47%)
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SETTING A VALVE. The proper and accurate setting of a valve on a steam engine is one of the most important duties that you will have to perform, as it requires a nicety of calculation and a mechanical accuracy. And when we remember also, that this is another one of the things for which no uniform rule can be adopted, owing to the many circumstances which go to make an engine so different under different conditions, we find it very difficult to give you the light on this part of your duty which we would wish to. We, however, hope to make it so clear to you that by the aid of the engine before you, you can readily understand the conditions and principles which control the valve in the particular engine which you may have under your management. The power and economy of an engine depends largely on the accurate operation of its valve. It is, therefore, necessary that you know how to reset it, should it become necessary to do so. An authority says, "Bring your engine to a dead center and then adjust your valve to the proper lead." This is all right as far as it goes, but how are you to find the dead center. I know that it is a common custom in the field to bring the engine to a center by the use of the eye. You may have a good eye, but it is not good enough to depend on for the accurate setting of a valve. HOW TO FIND THE DEAD CENTER First, provide yourself with a "tram." This you can do by taking a 1/4 inch iron rod, about 18 inches long, and bend about two inches of one |
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