In mechanical drawings cast iron is indicated by a series of straight lines across the parts made of this material. These lines can be quickly made with the usually discarded pencil stubs, if these are saved and sharpened in the following manner: The point is filed flat, as shown at A; then a slot is filed in the center of the lead with a knife file, as shown at B, and the points sharpened as in C. In this way two lines are drawn at one stroke neatly and in half the time.—Contributed by J. Kolar, Maywood, Ill.
To sharpen a carving knife draw the edge through and against the open edge of a pair of shears.
How to Build a Paddle-Wheel Boat
By P. A. Baumeister
The paddle-wheel boat, illustrated herewith, was built in the spare time I had on rainy afternoons and Saturdays, and the enjoyment I derived from it at my summer camp more than repaid me for the time spent in the building. The materials used in its construction were:
| 2 | side boards, 14 ft. long, 10 in. wide and 7/8 in. thick. |
| 2 | side boards, 14 ft. long, 5 in. wide and 7/8 in. thick. |
| 1 | outside keel board, 14 ft. long, 8 in. wide and 7/8 in. thick. |
| 1 | inside keel board, 14 ft. long. 10 in. wide and 7/8 in. thick. |
| 120 | sq. ft. of tongue-and-groove boards, 3/4 in. thick, for bottom and wheel boxes. |
| 1 | piece, 2 in. square and 18 in. long. |
| 4 | washers. |
| 2 | iron cranks. |
| 10 | screweyes. |
| 30 | ft. of rope. |
| Nails. |
The dimensions given in the drawing will be found satisfactory, but these may be altered to suit the conditions. The first step will be to cut and make the sides. Nail the two pieces forming each side together and then cut the end boards and nail them to the sides. Lay this framework, bottom side up, on a level surface and proceed to nail on the bottom boards across the sides. The ends of these boards are sawed off flush with the outside surface of the sides after they are nailed in place. The material list calls for tongue-and-groove boards for the bottom, but plain boards can be used, although it is then difficult to make the joint water-tight. When the tongue-and-groove boards are used a piece of string, well soaked in white lead or paint and placed in the groove of each board, will be sufficient to make a tight joint.