784 



Popular Science Monthly 



Removing the Point of a Broken 

 Center Drill 



WHEN centering shafts to be turned in 

 a lathe it often happens that the 

 center drill breaks off short. 

 It is then very difficult to 

 take out in most cases, but 

 the following method over- 

 comes the difficulty. Take 

 a small pair of spring divi- 

 ders and insert the points in 

 the flutes of the drill end. 

 Tighten the nut until you 

 have a firm hold on the dril 

 then simply pull it out. Be- 

 fore making the attempt to 

 draw out the broken part 

 it is quite necessary to 

 see that the drill cutters 

 are not stuck in the 

 metal as some damage 

 might result to the divid- 

 ers if they should slip off 

 when making the pull. 

 — Alfred W. Mardt. 



Pulling out 

 broken center 

 drill point 



A Safe Method of Joining Airplane 

 Sections or Wings 



JOINING together airplane sections or 

 wings is not a matter to be lightly re- 

 garded, when you consider the danger 

 to the aviator if a brace wire should break 

 during the flight. 

 The ordinary 

 method at pres- 

 ent in use is not 

 absolutely reli- 

 able; for, should 

 a brace wire 

 break, the strut 

 holding the top 

 and bottom 

 planes in posi- 

 tion may pull 

 out of its socket 

 and cause the 

 airplane to be- 

 come uncontrol- 

 lable. A sure 

 and safe way to overcome this danger is 

 clearly shown in the illustration. 



A U-bolt is used, each leg passing through 

 the ends of the horizontal pieces and 

 through the vertical strut and socket, 

 connecting the wing bars, socket and strut 

 all in one unit. Eyebolts, as used in the 

 present methods, will not hold the strut 



Tfl 3 — n^r 



U-bolt holding strut.socket 



and wings in one rigid 



unit.. 



A U-bolt placed at the 



joint of three pieces 



should a wire break. The U-bolt construc- 

 tion will not only hold the strut in position 

 should a brace wire break during the flight, 

 but it will also serve as wire terminals for 

 the brace wires. — Wm. Grotzinger. 



A Closet Rod Which Will Accommo- 

 date Several Suit Hangers 



A ROD or pipe fastened lengthwise in 

 your clothes closet will be found 

 a convenience. You can hook over it 

 several clothes hangers in such a way 

 that the clothes will not touch and can 

 be slid back and forth. Any narrow 

 pipe will do, or a fine self-made attach- 

 ment will be found in the "robe rails" 

 sold to auto owners for fastening in the 

 car tonneau. — Clarence F. Hubbard. 



Repairing a Broken Link in a Motor- 

 cycle Roller Chain 



A NOVEL yet very practical way of 

 making an emergency repair on a 

 motorcycle chain is illustrated. This 

 link is easily made by bending two 

 cotters of sufficient length and proper 

 size to the shape shown. The bent 

 end of the cotter is run 

 through the chain parts, al- 

 lowing the longer end with 

 the eye for the side plate. 

 As will be seen, the split end 

 of the cotter enters the eye 

 of the opposite one, where 

 clinched. 



These pins are not hard enough to 

 make a permanent repair, but they 

 will help a rider out in a pinch and can be 

 used until a more lasting link can be put 

 in the chain. — J. R. Schultz. 



Etching Photographs on the Surface 

 of Glass 



THE following is a simple method of 

 etching photographs on glass : 

 Cover the glass surface with a solution 

 of gum made sensitive with bichromate of 

 potash and print it under a negative. 

 After the image is thus produced, dust it 

 over with minium or red lead. The red 

 picture obtained is fixed and burnt in the 

 usual way. The easily soluble red glass so 

 obtained should be treated with strong 

 sulphuric acid, to produce a white matt. 

 The picture will appear by transmitted 

 light as a positive. — Herman Neuhaus. 



