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Page:Popular Science Monthly Volume 89.djvu/481

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Popular Science Mojithlj/

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��3^ in. thick, and J-g in. wide. A ,'4-in. hole was bored through this from end to end above the center or middle line. A pair of links of thin metal on each side were attached by pivot pins at the ends to the sides of the block, and afterwards one end of each link was detached and the block sawed through along the bore, after which the block was placed on the round bolt, which connected the two grooxed puilev's, and the ends of the links again attached.

By this arrangement the two parts of the block move back and forth a limited distance independently of each other, and in doing so clamp the belt between them. A triangularly-formed stop was attached to the upper member of the block, so that one edge projected down alongside one of the links, and thus limited the movements of the blocks relative to each other. The dotted lines show the swing of the links when the lower part of the block is drawn to the left.

To move the lower part of this block to the left, and thus grip the belt, attach a cross-piece by nailing to the lower ends of the table legs. The upper end of this arm is connected with the block by a link which is made of 3'8-'n- telegraph wire. A coiled spring with one end attached to the arm and the other to the table leg, serv-es to draw the upper end of the arm back, when it is released by the foot.

��The dead center was fi.xed to a block similar in all respects to the first block and is secured to the top of the table by screws so it can be moved to and from the block. A rest bar with a series of holes was adjustably attached to the lower sides of the blocks by bolts so if might be moved to or from the lathe centers. The square end of the mandrel, if dri\'cn into a round 5/i6-iii.-hole in the end of the piece to be turned, holds it firmly, and this method of attaching the work obviates the necessity of having thrust bearings for the mandrel and dead center. — J. S. Zerbe.

A Bottle Pocket Lamp

A SIMPLE and safe pocket lamp that will last for about si.x months with- out extra cost can be made at home.

Have the druggist take a strong vial of clear glass, or a pill bottle with screw or cork top, and put into it a piece of phosphorus about the size of a pea and fill the bottle one-third full of pure olive oil which has been heated for fifteen minutes. Care should be taken not to boil it. Cork tightly, and the result will be a luminous light in the upper portion of the bottle. If the light becomes dim, uncork and recork again. The lamp will retain its bril- liancy for about six months, and there is no element of danger in connection with it. — A. V. BOLLERER.

��The Method of Attaching the Work Which Is Indicated

Here Obviates the Necessity for Having Thrust Bearings

for the Mandrel and Dead Center

���GROOVED PULLEY "^

WHEEL UNK

��LINK

��-BLOCK

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