A Gate Cutter. Fig. 7 is a bent piece of sheet metal employed for cutting the gates from the bottom of the sprue hole to the edge of the mold.

A Vent Wire is a small wire used for making openings through the cope to provide for the escape of gases, and thus preventing blow holes in the casting.

Sand. Sand of the quality known as molding sand possesses in a large degree two desirable elements,- that of being porous, and of sticking together when moderatety moist. For small castings a fine grade of sand should be used. . Fine grained sand suitable for such castings is rather difficult to obtain, so the amateur had best get the sand from a foundry.

Figs. 5, 6, 7.

Parting Sand is a general term applied to any material used to prevent two surfaces of a mold from ad-hering. It is usually made from sharp or burned sand.

A Riddle is a coarse sieve used for sifting sand. The hand sieve is composed of a circular frame, the bottom of which is covered with wire cloth.

The Pattern should be finished with at least two coats of shellac varnish, made by dissolving gum shellac in alchol. The first coat should, when dry, be rubbed smooth with a piece of well worn sand paper.

The second coat should be somewhat thinner than the first. This will protect the pattern so that it is not affected by the moisture of the sand, and insures a smooth surface which draws easily from the sand.

Draft. A small allowance for draft is always made in the pattern to aid the withdrawing of the pattern from the mold. For small patterns a taper of 1/8 in. per foot is sufficient.

Mixing the Sand. If the sand obtained from the foundry has not been used for several days it is dry and must be mixed or "tempered" several times before being used for molding. The sand must be dampened with water and thoroughly mixed with a shovel. To test it, take a handful and press it together. If the sand be right to use it will form a lump showing the impression of the fingers, but should not be damp enough to stick much to the figers when the hand is opened.

Fig. 8.

To Mold the pattern, first lay the molding board on a bench and place the nowell on it bottom up. The pattern is then laid on the molding board, as shown in Fig. 9, and the sand is sifted from the riddle into the nowell until the pattern is covered to a depth of at least 1/2 inch. With the hand pat the sand down evenly over the pattern, being sure that none of the molding board is left uncovered. Next fill the nowell heaping full of sand with the shovel, and "ram up " the sand, care being taken to have plenty of sand, to ram uniformly and thus avoid layers. The peen end of the rammer is used to ram into the corners and next to the sides of the nowell, the rammer being held obliquely instead of straight up and down as is the case when the butt end is used. When somwhat more than full, the upper surface is scraped off with a straight edge and the bottom board laid on.

Now comes the second step. The whole is carefully turned over and the molding board removed. Be sure that in turning over the nowell the fingers grasp both the molding board and the bottom board firmly, so that the former will not move away from the nowell.

It will be seen in looking at Fig. 10 that all of the pattern comes in the nowell; but there will be an impression made in the cope of the hub and a portion of the pattern, as shown in the shaded part a. Fig. 9 represents the nowell rammed up with the two boards in place, before the nowell has been turned over.

Fig. 9.

Having turned the nowell over and taken off the bottom board, dust over the whole a thin layer of parting sand. Carefully blow off all parting sand from the pattern itself, and then set up the sprue pin within about 3 in. of the pattern, and force it down into the sand for 1/2 in. to hold it in place. Put on the cope, being sure that the pin holes are free from sand; also that the cope lifts off readily, and that the surfaces previously marked come together. Riddle on sand until the top of pattern is covered with at least 1/2 in. of sand. Fill the cope with sand and ram it up as the nowell was done, being very careful not to hit the sprue pin. Fig. 10 shows the flask rammed up with the pattern and sprue pin removed.

Fig. 10.

Next lift off the cope being careful to lift directly upwards. When the pins are free of the nowell, set the cope down on the bench, on one end, the top of the cope being toward the molder. If the top of the sprue pin is covered with sand, scrape it away until top is clear, aud then turn the sprue from the back, gradually forcing the sprue pin out from the mold. The prue pin is tapering so it will slip out easily after it is started. Be sure that the sprue hole is free from loose particles of sand. A draw pin is then driven into the middle of the top of the pattern, which is in the nowell, and the pattern loosened by gentle raps of the draw pin which is held by the left hand. The pattern is then lifted from the mold by means of the draw pin. As this particular pattern is circular in shape, it can be turned round by means of the draw pin, thus making sure that it is freed from the sand. A gate or channel about 3/8 in. wide and 1/4 in. deep, is now cut from the hole formed by the lower end of the sprue pin to the edge of the mold, using the gate cutter. Next run a vent wire several times through the cope, at points near the mold, so as to give vent to the gases. Replace the cope, being sure that the marked surfaces come together, otherwise the two halves of the mold may not be directly over each other.

Pouring the Casting.

In the manufacture of type metal, one part of antimony is used to four parts of lead, the antimony hardening and whitening the alloy and causing it to contract but little while cooling. Old type metal is readily obtained at almost any printing office, and can be bought for about eight cents a pound, being about one half the price of good babbit metal. Its melting point is not very high, and it can be melted in an iron melting pot over a bunsen gas flame in from 20 to 30 minutes time. For this small pattern the metal can be melted in a medium sized skillet. When the type metal is all melted, pour a little into some of the molding sand. If it sputters badly it is too hot for pouring. If it does not sputter, but pours freely without cooling in the skillet too quickly, it is ready for use. Take a stick and quickly skim off the top of the molten metal, or slag, as- it is called. Take the skillet, or whatever article the metal is to be poured from, carry it quickly to the mold, and pour the metal into the sprue hole in a steady stream, until the sprue hole is filled up with the molten metal. After five minutes the mold may be broken, and the casting examined, though care should be taken not to touch the casting with the hands until it is thoroughly cooled.