Page:Popular Science Monthly Volume 92.djvu/631

 Popular Science Monihlu

��form and by examining the drawing it can be seen that .1 and B are part of cones of the same size. C is a plain cylinder, the development of which has been ex- plained earlier in this series.

To develop the pattern for A: First, draw the complete cone with apex at D and base line at 1-9. Second, draw the one-half bottom view, divide it into eight equal parts, from these points project lines up to the base line and then to the apex, D. Third, with 1-D as a radius, strike the arc E-F, get the correct length by setting off sixteen spaces from the bottom view as previously explained and draw radial lines to apex D. Fourth, from where the curved part of the scoop crosses the radial lines going up from the base line to the apex, draw lines over to line \-D to get the true lengths as explained in the last issue. Swing these lines over on to the pattern until they cross the same numbered lines coming up from the arc E-F. Sixth, it will be noticed that the curve of the scoop in A does not cross the base line at the same place as one of the radial lines, so we must use an "aux- iliary" line such as we have used in a previous problem. This is used in the following manner: From the point where the scoop curve crosses the base line, draw a line to the bottom view and mark it X as shown in the drawing. It can be seen that it lies between 4 and 3. Measure the distance from 4 to X and lay it off on the pattern arc E-F as shown. This will indicate the corner of the pattern. Do the same for the opposite side of the pat- tern, and the pattern for A will be com- plete.

Exactly the same method is used in de- veloping the pattern for B. The steps are briefly indicated as follows: First, draw full cone. Second, draw one-half bottom view and run lines to apex K. Third, strike arc L-M with K-1 as radius. Fourth, draw lines from points where scoop curve crosses radial lines to line K-\, to get true lengths. Fifth, swing these lines in arcs to pattern. Make crosses where they intersect same num- bered lines. Sixth, make use of auxiliary line X in exactly the same way as for pattern A. Connect the crosses with a curve and the pattern is complete. Make allowance for seams and wiring as pre- viously explained.

��01.5

Cutting Asphalt After Removing

Metal Covering

ASPHALT is usually shipped in tin i\ barrels. The metal is stripped olf and the asphalt rolled up to the stopping board; the wire shown, attached to the

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��Cutting asphalt taken from barrel with a wire drawn through it with a windlass

winding drum, is passed over and around the asphalt to a piece of pipe under and ahead of the stop board. When the drum is turned it tightens up on the wire and causes it to cut through the asphalt. Kerosene is poured on the wire to make it pass through the asphalt easily.

��Asphalt with covei> mg stripped off-

��Cutting wire

��A- Loose end ot Aire fastened to pipe

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��' Diagram of the table, stop, and v/indlass for pulling the wire through the asphalt

The barrel shape is first cut in half, then each half is cut into quarters which a man can handle easily. In warm weather asphalt is soft, therefore it can- not be cut or broken with an ax or other tool, so this machine is a time and labor saver. — George C. Peck.

��Intensifying Under-Exposed Blue- Prints with Hydrogen Peroxide

AN under-exposed blue-print can be . intensified by moistening its surface with a sponge dampened with peroxide of hydrogen. Old blue-print paper which would otherwise produce an indistinct copy need not be thrown away if treated with peroxide after the print has been exposed and "fixed."

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