In furnaces of this kind the jet of a large gas blowtorch is to be used. If a standard is rigged up to hold the blowtorch, it will be much easier for the operator. The jet from the pipe is thrown in the hole at the side and a crucible is placed in the furnace. It is well to make a cover similar to the body of the furnace with a hole in the center a little larger than the hole in the side.
A more efficient furnace can be made with two holes in the side, opposite each other, for using a double jet from blowtorches.—Contributed by James H. Beebee, Rochester, N. Y.
The Magic Clock Hand
The hand, or pointer, is the only working part needed to perform the trick. A clockface can be drawn on any piece of white paper, and a pin stuck in its center on which the hand revolves. The hand A is cut from a piece of sheet brass, and may be in any form or design desired, but it must balance perfectly on the axle, which passes through a ¹⁄₄-in. hole in the center, or else the magic part will fail. The illustration shows a good design with dimensions that will cause it to balance well; however, this can be adjusted by removing some metal from the end that is heavier with a file or tinner’s snips, or a bit of solder may be stuck to the lighter end.
Design of a Hand That will Balance Well and the Parts for Its Axle
A disk, B, is cut from a piece of sheet brass, 1¹⁄₈ in. in diameter, twelve ³⁄₃₂-in. holes are drilled at equal distance apart near the edge, and a ¹⁄₄-in. hole is drilled in its center. This disk is soldered to the hand where both ¹⁄₄-in. holes will coincide. It is necessary to procure two washers, C and D, that are embossed, or raised, in the center, and about 1¹⁄₄ in. in diameter. These can be purchased from a dealer in curtain rods, the rod parts wanted being the washers used on the ends. A careful mechanic can raise the center portion of a brass disk by beating it over a hole with a ball-peen hammer.
One of the washers, C, has a spring, E, soldered at one end, and the other carries a small projection that will engage the holes in the disk, B. The projection can be made by driving the metal out with a center punch, set on the opposite side.
The washer D is provided with a lead weight, F, and a ¹⁄₄-in. stud, G, is soldered in the center. The stud has a ¹⁄₁₆-in. hole drilled through its center for the pin axle. The weight is made by filling the washer with melted lead, which when cold is removed and sawn in two. One piece is then stuck in the washer with shellac. The stud is ⁷⁄₈ in. long with the upper part, about ¹⁄₄ in. in length, filed, or turned down, smaller, and threaded. Just below the thread, or on the shoulder, the body is filed square to fit a square hole filed in the face washer C carrying the spring. This square hole and stud end are necessary in order that both washers may turn together.
