Fig. 74. SOME USEFUL STOCK MATERIALS MADE BY AUTOMATIC MACHINERY
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There are a number of different wire gages but the American Standard or Brown and Sharpe, or B and S as it is called for short, is the one mostly used by machinists in the United States.
Other useful gages are for the measurement of wood and machine screws; for finding the pitch of screws; for measuring the inside of tubes, holes, etc., and for measuring the outside of rods, tubes, etc. These tools and all others used by jewelers and machinists can be bought wherever tools are sold.
Buying Materials.—Many inventors waste time and sacrifice accuracy in making, or trying to make, wheels, gears, threaded rods, nuts, binding posts, contact points, switch levers and blades, hard rubber knobs, handles and other parts.
Now all of these things and hundreds of other parts can be bought ready made of model makers, gear works and dealers in hardware, model aeroplanes, electrical and wireless apparatus. And before you begin a model of any kind you should get catalogues from all of the supply houses you see advertised. Fig. 74 shows quite a number of parts you can buy ready made.
About Making Patterns.—Very often though you will have to make a special part out of metal or have it made. Like everything else there is a best way to do this.
Suppose you need a standard something like that used for a telegraph sounder, as shown in Fig. 75. To saw and file out a solid piece of brass would not only take a long time but it would prove a very tedious job; and this is also true of many other parts you will need in the course of making your model.