A Shaft Coupling
In connecting a small 1/8-hp. motor to a small air pump where both shafts were 3/8 in. in diameter, I quickly made a coupling that would save the wear on the machines, as follows. The coupling was made of a piece of 3/4-in. brass rod with a 3/8-in. hole drilled through its center. One end of the hole was enlarged to 7-16 in. for about 7/8 in. The end of the coupling having the small hole was slipped on the pump shaft and fastened with two setscrews. The other end was drilled to take a pin loosely, the pin fitting tightly in a hole drilled in the motor shaft. The pin was bent at one end so as to keep it from falling out and the other end fitted with two nuts. The motor shaft being a little loose in the coupling, gave it a chance to work free without binding.—Contributed by Leo J. Werner, New York City.
Coupling on the Shafts
Reading the Date of a Worn Coin
The date and denomination of a coin worn smooth can be determined in the following manner: Take an ordinary coal shovel, or a piece of sheet metal, and place it in a hot fire. Allow it to become red hot, then remove, and place the coin on the hot surface of the metal. Any figures or letters can be readily seen when heated in this manner. This test seldom fails even when the inscriptions have been worn so smooth that they are invisible to the naked eye.
Making a Knife an Easy Opener
The large blade of my knife being so hard to open placed me in constant risk of breaking my thumbnail. To overcome this difficulty, I ground a notch in the handle as shown in the sketch. After smoothing it up with a round file and fine sandpaper, I had just as good a job as if the knife had been made that way, and it is very easy to open it, as it can be done with the thumb and forefinger. Anyone can improve his knife in this way, but be careful not to cut the notch back of the point of the small blade.—Contributed by C. M. Mahood, Warren, Pa.
Notch in the Handle