The accompanying sketch shows a plan I adopted for conserving the waste heat from my furnace. I found that I was able to put a coil into the smoke pipe, which was about 8 in. in diameter, and thus heat water for domestic purposes. It will be seen that the coil is spiral in shape rather than cylindrical, as the latter would leave a free passage up the center and therefore would not bring enough gases into contact with the coil.
In addition to this coil I have a gas heater near the tank which is used only in case the demand for hot water exceeds the capacity of the coil, which is naturally not as efficient per unit of length as one directly within the firepot would be. It has the advantage of not absorbing heat which should go to make steam, but only that which would otherwise be wasted. The heating surface of the coil is much greater than would be possible within the firepot, which in a measure compensates for its lower efficiency.—Contributed by W. E. Morey, Chicago.
A Homemade Marking Gauge
A 3/8-in. bushing is turned into the side outlet of a 3/8-in. tee. The bushing is then tapped to receive a 7/16-in. wing bolt. A tight-fitting wood plug is driven into the throughway of the tee and the ends ground off flush on the emery wheel. A slot, 5/16-in. square, is then cut through the wood plug just under the bushing. Two pieces of flat steel, each 1/4 in. wide by 1/8 in. thick and 1/8 in. longer than the tee, are fitted in the slot cut in the plug as shown in the sketch. The outer end of each piece is bent at right angles and sharpened. After the points have been drawn out to the right distance, the wing bolt is turned to hold them in that position.—Contributed by C. Molloy, Philadelphia, Pa.
Protecting Brush Handles from Paint
A very efficient method to prevent paint from running down on a paintbrush handle and on the hand is to cut a hollow rubber ball in half, Fig. 1, make a hole in the center to fit the brush handle and attach it as shown in Fig. 2. One ball will fit up two brushes. The cup shape catches the paint and prevents it from getting on the handle.—Contributed by O. H. Meyer, Churdon, Iowa.
The Shape of the Ball Forms a Cup to Catch the Paint from the Brush (Fig. 1, Fig. 2)