faces, an ordinary chisel is mostly employed, the position in which it is held to the work causing it to scrape rather than cut. A worn-out paring chisel is as good as any. Such a chisel is shown in Fig. 64, the position in which it is held being illustrated by A, which represents a section of a piece of cylindrical work; B representing the chisel, and C the hand rest. Some pattern makers prefer to increase the keenness of this tool by holding it so that the plane of its length lies in the direction denoted by the dotted line, D; this, however, renders it more likely to rip into the work, and the position shown is all that is necessary, providing the cutting edge be kept properly sharpened. This chisel is also used on side faces.

Still another tool, sometimes used for finishing plain cylindrical surfaces and side faces, is that shown in Fig. 65, at A. It is used in the same manner and relative position as the chisel shown above, in Fig. 64.

For finishing hollows, which should first be roughed out

A

Fig.65. B

C

D

with the gouge, the form of tool shown at B, in Fig. 65, should be used. Several of these tools, of various sizes, should be kept; they are used in the same position as the

finishing chisel, shown in Fig. 64. The tool shown at C, in Fig. 65, is used upon large work, and is advantageous because it presents less surface of cutting edge in proportion to the depth of the cut than the gouge; and, in consequence, it is less liable to cause the work to jar or tremble. It is usually made about 2 feet long, which enables the operator to hold it very firmly and steadily. It is used with its top face lying horizontally, and should be kept keen.

D, in the same figure, represents a similar tool, with a round nose; this latter is not, however, made long, and may be used in a handle.

For boring and shouldering purposes, the tools shown in Fig. 66 are employed; those shown at A and B, having their cutting edges at C and D, are therefore right and left hand tools. When, however, the hole is too small to admit of those tools being used, that shown at E may be employed, its cutting edge being at F.

The temper of all these tools should be drawn to a light brown color, and the instruction given for grinding bench tools should be rigidly observed in grinding

and oilstoning these turning tools.

HOW A PATTERN IS MOLDED.

It has been already remarked that the operations of the molder are, to a large extent, predetermined by the pattern maker; hence it becomes necessary that the latter shall have a knowledge of foundry work, otherwise he is likely to make the patterns very expensive and awkward to mold. In learning the trade, an apprentice is usually put to work and distinctly instructed as to the required form of his work, without knowing anything of the reasons therefor. In this way he attains a practical knowledge of how different classes of patterns should be, or are, usually made; but it takes him years to become an expert mechanic, for the reason that, having learned by rote, he is incapable of meeting new conditions to the best advantage, until his experience has included both observations in the foundry and, in some cases, consultations with foundryBefore entering, therefore, into the method of putting together different kinds of pattern work, it will be well to take a glance at the foundry, and examine the contrivances and the operations of the workmen, so that our operations in pattern work may be intelligently made from the beginning.

men.

The floor of the foundry first demands our attention. It is composed of a layer of molding sand of sufficient depth to imbed patterns of the size usually cast in that foundry. For exceptionally large work, there is usually a place where the natural earth has been excavated to a greater depth; the cavity is filled with molding sand. This place is usually within easy reach of the crane (which commands

4

almost every part of the floor) and the threshold of the melting furnace or cupola. We next observe the capacious oven for baking cores and drying molds for such special work as may require these operations; but the particular contrivance with which the pattern maker has now to concern himself is represented in Fig. 67. It is called a flask, and is composed of two or more parts (two only being shown in the engraving). The lower part is

B

Fig.67.

mr

called the nowel, and the upper the cope. Each part is simply a strong rectangular frame of wood or iron. The sides, being continued past the rectangles, are roughly shaped for use as handles. The cope is provided with several crossbars, which embrace the pattern, as it were, being roughly shaped like it in contour and approaching

it in size, being about half an inch larger all round. These bars, by their adhesion, support the body of the sand in the cope, and in this they are frequently assisted by nails driven nearly half way into them. When an intermediate part is used with the two parts shown in Fig. 67, the contrivance is called a three-part flask; with two intermediates it is called a four-part flask, and so on. As the cope is provided with crossbars, so also the intermediates, having to lift a ring of sand, are provided with wings; that is to say, as much crossbar as will extend from the sides to within about half an inch of the pattern. The parts are guided, in their position one to the other, by taper pins on one part fitting into eyes fixed to the other part, as shown in Fig. 67, in which the cope is shown with the side having the two pins exposed to view, while the opposite side of the nowel, having one eye, is visible. In many cases, and for large work, the nowel is dispensed with, and the foundry floor is used in its stead, in which case the cope is guided to, and retained in, its place by stakes driven into the floor sand, as shown in Fig. 68, so that, when lifted to admit of the pattern being drawn from the mold, the cope may be returned to its exact proper and former position. In Fig. 68, A represents the pattern whose impression iu the floor sand, at M, forms a part of the mold. B represents the cope; for the word cope is usually applied to the upper part of the mold as well as to that portion of the flask which contains it. The top print, C, of the pattern, has formed its impression in the cope at P. R is a round taper peg, which leaves a hole in the cope at r, through which hole the molten metal is poured. It also leaves an indentation at r'; and from this latter a gutter is made by the molder to communicate with the mold, M, as shown. The stakes referred to above are marked S. The dots, shown around the impression of the top pattern print, C, in the cope, are small holes made in the sand (after the