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 



