Page:Popular Science Monthly Volume 90.djvu/636

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��Popular Science Monthly

��Removing Small Bronze Bushings That Have Become Worn

IN certain machines it is necessary at times to remove bronze bushings which have become worn and are so located that it is impossible to drive them out. Chipping takes too much time. The sketch shows a method which is very easily applied in such cases. A bolt of sufficient length, A, is used through the bushing and a piece of pipe B is placed as shown. The length of the pipe should be equal to the thickness of the part, C; the diameter of the pipe should be a little larger than i:he outside diameter of the bushing.

A large washer or a short piece of bar iron may be used at D. The head of the bolt should be slightly smaller than the outside diameter of the bushing; then by turning the nut the bushing is easily re- moved. — ^J. P. Harner.

���Drawing a bronze bushing with bolt

��Drawing a Nail Easily After Striking It a Blow with a Hammer

A NAIL not driven entirely in and which has become so rusted that it cannot be withdrawn without breaking a hammer handle, will come out easily if it is struck a smart blow first. The same holds true with a screw; if it will not turn out, try turning it in first. These suggestion may not always work, but many times the trouble may be overcome by their use.

��Smooth Tone Phonograph Diaphragm Made of Telephone Transmitter

AN electric attachment for the ordinary L phonograph or victrola can be used with pleasing results in place of the diaphragm sound reproducer and horn. It is necessary to unscrew the diaphragm from the swivel and substitute in its place a small, light telephone transmitter from which the rubber mouthpiece has been removed. The transmitter can be held in place by wires or a removable clamp. To one of the sides of the transmitter a tungsten needle is soldered. Ordinary soft tone or loud tone steel needles can be used, but they have to be replaced so frequently that the task becomes tedious.

��The weight of the transmitter may be regulated with small rings of lead. The needle should bear upon the phonograph cylinder surface with the same pressure as is exerted when it is used ordinarily.

Small flexible silk-covered lamp cord should be connected with the terminals of the transmitter, and led to the back of the phonograph and to a battery and a tele- phone receiver. Sensitive receivers are not necessary. It is advisable to use double re- ceivers fitted with a head band. One fresh cell of the dry battery type will be sufficient. The proper connections are shown in the accompanying diagram. A fifty-ohm vari- able resistance should be inserted some- where in the circuit.

When the phonograph is started, the notes of music will be heard in the telephone receivers with perfect clearness, the usual scratching sound being almost entirely elim- inated. By adjusting the resistance box the tones can be made loud or soft at will. If the record is old and badly scratched, the customary grating noise can be "tuned" completely out by adjusting the rheostat.

The explanation of the operation of this device is that, contrary to the usual grapho- phone sound-enlarging arrangement, the electric system does away almost entirely with sound distortion. It is impossible to construct a phonograph horn which will not distort the sound. On short distance telephone systems, if they are properly constructed, the distortion of the sound is hardly appreciable. The sounds which emerge from the receivers when the trans-

��Telep^one TranomiHer

���Jungaten '' Needle

��m

���Tet. Receixrer

��50 Ohm ffesisfontt

��Tronsmiffer L- DryCelh

A telephone transmitter used in place of the sovmd-producing diaphragm of a phonograph

��mitter is used with a phonograph record are consequently nearly pure. The music sounds as if it comes from a distance, almost resembling the sound of music coming across the water.

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