F. W. PUTNAM

The next pattern to be taken up is that of a bevelled wheel suitable for a turn-table and is shown in Fig. 71. If we examine the top view of this figure we shall notice that the pattern will require a three-part flask. One great principle in pattern making, which should always be remembered, is to use as few loose or separate pieces on the pattern as possible and so make the parts with the greatest amount of metal inserted in the lower half of the flask. Let us examine Fig. 71 to see how this rule may be applied to the pattern under consideration.

Make the rim of the pattern at the smaller end, A, as a separate or loose piece. We shall find that, if the pattern is to be carefully made, it will be advisable to start at that part of the pattern known as the web shown at A, in Fig. 72. First, build up that portion of the wheel which will be molded in the nowell. This will be the largest side of the wheel. Saw out of boards circles sufficiently large for the work, gluing the pieces, one on top of the other, until the required thickness is obtained ; remembering that where a pattern is built up the successive layers of stock are to be placed with the grain running in the opposite direction, so to prevent warping. If a larger pattern for a bevelled wheel were required, the better way would be to glue up the rim in sections or segments, as they are called. In such a case the hub would be the only solid part of the pattern and the hole for the shaft would, of course, be cored out. Having built up the stock for the pattern, the glue having become thoroughly hard, fasten the block into a chuck and turn to the required size. It will be found advisable to make two templets, as shown in Fig. 73 to 75.

The templets shown in Figs. 73 and 74 should be used first in truing up the faces and turning down the rim to the proper dimensions. The part marked A in Fig. 74 should be very thin, not over 1/8 in. in thickness, and may be nailed or glued to the other piece. This part, A, is exactly the same shape as the pieces B in Fig. 72. These pieces are to be cut out on the other side of the block, and the edge of the rim at C, Fig. 72, is to be turned. The pattern is now to be removed from the chuck and the other side built up, the block being first chucked so that the web may be evened off to the required thickness. Next build up the pattern so that the total thickness will be slightly greater than the finished pattern. It will be found advisable to build up the pattern while it is fastened in the chuck. When the pattern has been built up and the glue has become thoroughly dry, face up and true off both the inner and outer edges. Be very careful in turning the shoulder on which the loose rim is to set, so that perfect joint may be made when the loose piece is finished. The loose piece may be made in one piece, though it is far preferable to make it from at least two pieces, so as to prevent warping to as great an extent as possible.

The stock for the loose rim should be chucked and turned down so that the rabbet, which is necessary in order that the loose rim may be set on the rest of the pattern, will fit evenly to give the exact thickness for the total pattern.

The templet shown in Fig. 75 is used to test the exact shape of the outside of the bevelled wheel, and should be carefully made. The loose rim must turn freely, having a very small amount of glue, as it is glued so as not to stick to the main part of the pattern.

The core prints are, of course, turned separately and fastened to both sides of the pattern. The core box is not shown, as it involves no new work and no trouble should be experienced in making it.