If you do not
possess a lathe, lay the tube on the sheet metal, and with a very sharp
steel point scratch round the angle between tube and plate on the inside.
Cut out with cold chisel or shears to within 1/16 inch of the mark, and
finish off carefully--testing by the tube now and then--to the mark.
Make a dent with a centre punch in the centre of the top plate for the top
to spin in.
[Illustration: FIG. 75.--Wheel of steam top, ready for blades to be bent.
A hole is drilled at the inner end of every slit to make bending easier.]
Solder the plates into the tube, allowing an overlap of a quarter of an
inch beyond the lower one, to help retain the heat.
The top wheel is cut out of a flat piece of sheet iron, zinc, or brass. Its
diameter should be about 2-1/2 inches, the vanes 1/2 inch long and 1/4 inch
wide at the circumference. Turn them over to make an angle of about 45
degrees with the spindle. They will be more easily bent and give better
results if holes are drilled, as shown in Fig. 75.
The spindle is made out of a bit of steel or wire--a knitting-needle or
wire-nail--not more than 1 inch in diameter and 1-1/2 inches long.
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