Procure some brass, about 3/16 in. thick and 4 in. square; 53 steel pens, not over 1/4 in. in width at the shank; two enameled, or tin, saucers or pans, having a diameter on the inside part of about 4-1/2 in.; two stopcocks with 1/8 in. holes; one shaft; some pieces of

[Illustration:  Details of Turbine]

brass, 1/4 in. thick, and several 1/8-in. machine screws.

Lay out two circles on the 3/16-in. brass, one having a diameter of 3-1/2 in. and the other with a diameter of 2-3/4 in.  The outside circle is the size of the finished brass wheel, while the inside circle indicates the depth to which the slots are to be cut.  Mark the point where a hole is to be drilled for the shaft, also locate the drill holes, as shown at A, Fig. 1.  After the shaft hole and the holes A are drilled in the disk, it can be used as template for drilling the side plates C.

The rim of the disk is divided into 53 equal parts and radial lines drawn from rim to line B, indicating the depth of the slots.  Slots are cut in the disk with a hacksaw on the radial lines.  A small vise is convenient for holding the disk while cutting the slots.

When cutting the disk out of the rough brass, sufficient margin should be left for filing to the true line.  The slots should be left in their rough state as they have a better hold on the pens which are used for the blades.  The pens are inserted in the slots and made quite secure by forcing ordinary pins on the inside of the pens and breaking them off at the rim, as shown in Fig. 4.

When the pens are all fastened two pieces of metal are provided, each about 1 in. in diameter and 1/32 in. thick, with a 3/8-in. hole in the center, for filling pieces which are first placed around the shaft hole between the disk and side plates C, Fig. 1.  The side plates are then secured with some of the 1/8-in. machine screws, using two nuts on each screw.  The nuts should be on the side opposite the inlet valves.  The shaft hole may also be filed square, a square shaft used, and the ends filed round for the bearings.

The casing for the disk is made of two enameled-iron saucers, Fig. 2, bolted together with a thin piece of asbestos between them to make a tight joint.  A 3/4-in. hole is cut near the edge of one of the saucers for the exhaust.  If it is desired to carry the exhaust beyond the casing, a thin pipe can be inserted 1/4 in. into the hole.  Holes are drilled through the pipe on both inside and outside of the casing, and pins inserted, as shown in Fig. 5.  Solder is run around the outside pin to keep the steam from escaping.  At the lowest point of the saucer or casing a 1/8-in. hole is drilled to run off the water.  A wood plug will answer for a stopcock.

If metal dishes, shaped from thick material with a good coating of tin, can be procured, it will be much easier to construct the casing than if enameled ware is used.  The holes can be easily drilled and the parts fitted together closely.  All seams and surfaces around fittings can be soldered.