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Page:Popular Science Monthly Volume 90.djvu/485

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How to Make an Electric Heater

One of three hundred and twenty-six watts capacity is easily constructed

Bv Roland Jens

��A SMALL electric heater, although sHghtly more expensive to operate than a wood or coal stove, is ideal for a bedroom, or rooms that are not re- quired to be heated at all times. The heated air from an electric heater is as pure as the air in the room in which it is placed, while if the same room is heated with a coal stove, poisonous gases es- cape. Details are shown in Fig. I. The work may be divided into the follow- ing parts:

(i) Construction of cyl- inders.

(2) Construction of legs or base.

(3) Winding of cylinders.

(4) Construction of cover plate.

(5) Assembly.

(6) Connections. First the sheet iron plates

are to be cut. Sheet iron of 1/32 in. thickness should be used, but if this cannot be obtained, plates slightly thicker or thinner will do. Cut the plate for the 12-in. cylinder (Fig. 6). In order to make the corners exactly 90", lay off a base line on the plate from which you are to cut and with a car- penter's square lay off on the base line two right an- gles 38% in. apart.

Lay off 18 in. on the two lines which form a right angle with the base line. Connect the two points by a straight line, and you will have a rectangular plate. The 3^-in. holes are now drilled or punched. Drilling is preferable as it gives a better and more accurate hole than punching. After the plate for the 12-in. cylinder is done the plates for the other four cylinders are laid out and drilled in the same manner.

���Fig. 1. Top, eleva- tion and base plan of electric heater

��The next step is the rolling and rivet- ing of the sheet iron plates. If a roller for rolling sheet iron is at hand this part becomes easy, but if it is not, other means will have to be resorted to. One alternative is to bend the plates over a round wooden cylinder or gas pipe which is of about the same diame- ter as the cylinder. As the metal is thin, it can be easily bent in this way with rea- sonable accuracy. After the sheets have been bent, rivet the upper five holes with 34-in- soft iron rivets 3/16 in. long. The lower hole is not riveted at this time because the cylinder is fastened to the base by means of this rivet. If the cylinders are not quite round, due to improper bending, they may be rounded off by placing them on a fairh- large piece of gas pipe and pounding them into shape with a maul.

The legs or stand of the heater are made of two strips of sheet iron }/g in. thick, I in. wide and 17 in. long. (Fig. 11). Center- punch the middle of each piece and lay off the /^-in. holes, as shown in the draw- ing. Drill the holes and file off the burrs caused by drilling. To bend the ends into the shape shown, grip the strip and a ;^4-in. bolt in a vise and pound the metal until it closes around the bolt the desired dist- ance. Remove the bolt and strip. Turn the strip around, tighten in the vise again with the bolt and pound with a hammer to get the second curva- ture. Do this to each end and then rivet the two together with a ^-in. rivet through the center hole.

The next parts to be made are the ^

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