Page:Popular Science Monthly Volume 91.djvu/456

 Standardizing the Die-Sinker

An automatic machine which can produce fifteen dies in the time formerly required to make one

By Herbert F. Sherwood

��WHEN you have four hundred drop forgers to keep busy and wish to turn out from 200,000 to 250,000 forgings in the course of every twenty-four hours* you begin to take thought as to how you can save in the necessary opera- tions. Do any pieces require three different manipulations when two will answer ? Are there any machines, or can any be invented to reduce hand work?

One of the necessary details of making drop forgings, of course, is that of producing the dies. The pattern's the thing. It must be exactly right, cut to the one- thousandth part of an inch of the desired dimensions. In making rifles the dies must fit so closely together when the hammer comes down that the "flash" — in other words, the excess metal which spreads out around the forging between the two dies, will be like paper for thin- ness. The thinner the flash, within reason, the greater the production from the trimming presses which later cut off the halo of metal.

In a Bridgeport, Conn., plant a way has been worked out not only of standard- izing the process of making dies to serve as models, but of adapting the principle used in copying statues and making jewelers' dies by ma- chinery, to the sinking of larger dies. In the making of a standardized article, such as a bayonet, however, and where consider- able numbers of large dies are required, it has been demonstrated that it is practicable and economical to plan out in advance the different operations required in the making of a given die and specify them on a card of directions accompanying the block of metal from which the die is to be made. The outline of the desired die is drawn upon the coppered surface of the block

��SPRING PENCIL-LIKE

STYLUS COMPLETED MODEL

���By means of this machine one die can be made in eight hours. One man can supervise three machines

��and the directions specify what cuts shall be made, and the exact depths which shall be given to them. The cutting tools that shall be used are also named. One work- man may not necessarily perform all of ■the work. Some of it may not require an expert's attention.

The model completed, it is put into a machine which carries also an uncut block. This machine is equipped with two arms connected so that they will work like a pantograph. At the end of one of these arms is a pencil-like stylus of metal whose point, pressed against the model, follows every indentation in and out. To the other arm is attached another stylus, also about the diameter and shape of a carefully sharpened pencil. This one, made of very hard steel, revolves so rap- idly and smoothly that its cutting edges can- not be seen. As the upper stylus moves up and down across the face of the model in parallel vertical lines five one-thousandths of an inch apart, the fast flying pencil-like stylus below follows suit across the uncut surface of the lower block. With the same undeviating evenness of speed that characterizes the movement of the earth around the sun, it engraves a reproduction of the model.

Ordinarily, by the old methods it would require one man's time for from thirty-six to forty hours to produce the die. By means of this machine, the same work can be done in eight hours, and one man can supervise three machines. In this way fifteen dies can be produced by him in the same length of time which was formerly required for one. Owing to the more automatic character of the work, a less experienced man can be employed for this part of the operation at less cost.

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