Page:Popular Science Monthly Volume 88.djvu/789

 Popular Science Monthly

��761

���A revolving drawing-board of this design can be made by an amateur

Construction of a Revolving Drawing- Board

A DRAWING-BOARD that revolves will be of interest to many ama- teur draftsmen. The following dimen- sions may be altered according to the materials that the builder has on hand. Procure a board, 3^^ in. by 1 8 ins. by 24 ins., of any soft wood. By measuring down from the top of the board 9 ins. and in from the side 1 6}^ ins., establish a point and describe a circle of 15 ins. diameter.

Prepare another board of the same dimensions, with a circle of 14}^ ins. diameter. By means of a band saw, remove the disk within the circle of each board. Glue the two boards, W and 5 together, the centers of the two circles co- inciding. The two disks, SY and WY, should be similarly glued together. Glue two rectangular strips of hardwood E, I in. by 2 ins. by 18 ins., on the ends of the rectangular boards to prevent warp- ing.

Make two pulleys A, 4 ins. in di- ameter, with a V-shaped edge. Attach one pulley to the bottom of the circular board. Measure from the left side of the rectangular board 5^ ins. in on the center line and drill a ^-inch hole. Into this hole, force a piece of brass tubing, % in. long, and having an inside

��diameter of 3^ in. In the top board, make a rectangular opening, 6}^ ins. by 3^ ins. by 3^ in., so that the small hole just made will be at the middle of the lower long side, as shown in the diagram. At this point, fasten a protractor.

A short piece of steel rod, 3^ in. in diameter, must be threaded at one end. Attach a needle or pointer, such as a clock-hand, to the other end and place the rod in the brass tubing. Fasten the other pulley to the under, threaded end by means of nuts. Pass a thread around the two pulleys and tie it securely. Rubber tacks should be driven into the bottom of the board at the four corners. The dial may be kept clean by means of a piece of glass, 63^ ins. by 3^ ins. By adjusting the index finger, the revolving board, with its drawing, can be set at any angle which may be desired. — H. Alexanderson.

The Construction and Use of a Safe Driving-Box Lifter

THE device illustrated is for lifting driving-boxes with a traveling crane, for use with planers, boring-mills, drill- presses and the like. It is made from two forgings and a ^-in. chain. The two rectangular links are made from 3/4-m. iron. The ring is made first, then the rectangle, and lastly the two are welded. They slip over the driving-box as shown. As soon as the crane-hook is hoisted, the two links are drawn together. An accident is practically impossible. The size of the link can be made to fit any driving-box, though it can be used for any box it will go over. The only exception is when the box is too small. — Joseph K. Long.

��CRANC HOOnX i-CHAIN

APPLICATION

��3

���Lifting the driving-box of a locomotive is simplified by this device

�� �