THE WORLD'S ADVANCE 



79i 



Locates Centers of Pipes and Fittings 



To locate the centers of pipes, elbows 

 and other fittings, a wood tool can be 

 used which will give accurate results. 

 A triangle should be cut from ^-inch 

 board, and glued tightly to a pocket rule. 

 If an elbow is to be centered, it should 

 be placed upon a smooth surface, and 

 the triangle inserted. The exact center 

 line will be found by consulting the 

 ruler. The distance between centers of 

 two pipes disposed in parallel can be 



Length of cross p/oe 4 fod 



found by using two of these triangles 

 and measuring the distance between their 

 center points. 

 Contributed by 



ARTHUR L. KREBAUGH. 



Novel Tubes for Loose Couplers 



If the paper or cardboard which is 

 used in making loose coupler tubes for 

 wireless receiving sets is soaked in flour 

 paste, a much stiffer tube can be made 



Jheef iron 

 Jtee/ 



To Saw Thin Metal Strips 



The uneven, ragged edge which usual- 

 ly results in an attempt to saw thin metal 

 strips can be prevented if the stock is 

 clamped tightly in a vise between two 

 parallel steel bars. The cut should be 

 made with the hack saw guided by the 

 smooth surfaces of the bars. 



Contributed by 



C. P. CLEARY. 



Electric Signals for Directing Tractors 



Nearly all road graders are drawn by 

 traction engines, and considerable diffi- 

 culty is encountered in conveying the 

 "stop/' "go ahead," "go to right" and 

 "go to left" signals from the grader to 

 the man driving the traction engine. This 

 difficulty may be overcome by the use of 

 an electrical signaling system, which is 

 quite easy to construct and is certain in 

 its results. 



The signaling apparatus should be at- 



than by the ordinary methods. Heavy 

 paper is preferable to cardboard. 

 Contributed by G. L. PETTYCREW. 



tached to the engine so that it is in full 

 view of the engineer. Two miniature 

 electric lamps and a door bell will be re- 



