F. W. Putnam.

Type metal has been used with good success by the writer in the casting of small patterns, the castings obtained being generally very smooth and with very few blowholes.

The purpose of this article is to explain as clearly as possible the processes of molding and casting a simple pattern in type metal. For the pattern we will take a small car wheel. Fig. 1 is a drawing of the wheel, giving all the necessary dimensions. The pattern should be made of clear dry pine, and can be obtained at small cost from any wood turner.

Moulding and Casting Type Metal Patterns 300

Fig. 1.

The following terms are the ones most common to founding, and will be used frequently in this article.

Flask. A flask is a frame or box that keeps the sand in place while the casting is being made, holding both pattern and sand. In its simplest form a flask may be described as a pair of boxes of similar shape and size, but without top or bottom. These boxes are prevented from separating horizontally by suitable pins, which however permit ready separation vertically. Two flat surfaces made of boards with cleats in one side complete the apparatus. Generally both boxes or "halves" are of the same depth. The lower half of the flask is called the "nowell" or "drag," and contains the holes for the pins. The upper half is called the "cope," and contains the pins which fit into the holes bored for them in the nowell. The nowell rests on the bottom boards.

The two flat surfaces spoken of above are alike, one being called the "molding board," and the other the "bottom board." The molding board is the board or plate upon which the pattern is placed while "ramming" the sand into the nowell. The bottom board is the board or plate which is placed on the top of the nowell before turning it over, and hence it becomes the bottom of the mold during subsequent molding and casting operations.

Moulding and Casting Type Metal Patterns 301

Fig. 2.

Fig. 2 shows the pieces used in making the flask. Clear well seasoned spruce should be used for this, as it will stand the moisture of the sand better than pine, though the latter may be used if spruce cannot readily be obtained. After these pieces have been cut out, cuts about 3-16 in. deep and 1-2 in. wide are made with a carpenter's gouge on the surfaces which will be the inside surfaces of the finished flask. These cuts are of use in holding the sand in place after the flask has been rammed up.

Fig. 3 shows the cope after being put together. The pieces should be fastened with 11/2 in- wood screws No. 10 guage. A steel wire nail should be carefully driven down through the two side pieces at each of the points marked "X" in Fig. 3. Be sure that the nails are driven perfectly straight, otherwise there will be difficulty in lifting off the cope easily from the nowell. These nails should be either 10 penny (3 in.), or 12 penny (31/2 in.), the latter being preferable. The nowell, which is made exactly the same as the cope, m ust have a hole bored through each of the two sides corresponding to those of the cope, into which the nails are to fit. The hole should be 1/4 in. diam. so as to give a little freedom of movement to the nails or pins as the cope sets down on the nowell. These holes should be bored clear through the sides so that the sand, which is very likely to clog the holes, can be readily punched through with a small stick.

In looking at Fig. 10 it will be noticed that four strips marked "d," two on each half of the flask, are screwed to the sides containing the pins and tne pinholes, heing flush with the top of the cope and the bottom of the nowell. These pieces, which aid in lifting the cope from the nowell, are $ in. x 10 in., and are fastened with 11/2 in. wood screws No. 10. Care should be taken in making a good joint between cope and nowell. When the cope has been fitted to the nowell and found to work easily, mark plainly the corresponding surfaces of the cope and nowell in two places.

Moulding and Casting Type Metal Patterns 302

Fig. 3.

The molding board and bottom board should be made of clear dry spruce matched boards 3/4 in. to 7/8• in. thick. They are of the same size as the fiask, and have two pine or spruce cleats on one side, as shown in Fig. 8 to prevent the boards from warping.

The above is a description of a flask which will serve admirably for the molding of almost any small pattern, the thickness of which does not exceed 11/2 in. if the pattern is molded wholly in the nowell, or 3 in. if pattern is molded part in each half, as would be the case in a split pattern.

If the amateur does not care to take the time to construct such a flask, he can easily make something temporary to answer the purpose, but if one intends to do much molding I should advise the making of a flask of suitable size for the work to be attempted.

Fig. 4 shows sketches of a rammer. For work with this flask the rammer may be made from pine, though maple will wear much better. For light work but one is necessary. A rammer is a tool used for tamping the sand in the mold. One end has a flat rectangular point called a "peen," and the other end has a large flat surface called a " butt."

A Draw Nail, is a metal piece used in drawing a pattern from the mold. A long wire nail filed down to a long point, as in Fig. 5, will answer the purpose.

Moulding and Casting Type Metal Patterns 303

Fig. 4.

A Sprue Pin is a wooden or metal pin, used for making an opening through the cope, through which the metal is poured. Fig. 6 shows a sketch of a sprue pin which can be made of pine. It should gradually taper downwards so that it can be readily removed from the sand. The position of the sprue pin with relation to the pattern will be described later.