Page:Popular Science Monthly Volume 91.djvu/800

This page needs to be proofread.


��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


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.

�� �