4G4 



Keeping Vise Jaws Open with a 

 Coil Spring 



EVERY mechanic knows what it is to 

 work with an old vise where the screw 

 and nut are so badly worn that it becomes 

 necessary to back the movable jaw farther 

 than necessary when inserting the work. 

 The trouble 

 caused by this 

 back lash can be 

 eliminated by 

 the spring shown 

 in the illustra- 

 t i o n. The 

 spring A is in- 

 serted between 

 the two jaws 



and kept in place by two plugs B, which are 

 driven into holes drilled in the jaws. It is 

 evident that, as the handle is turned back- 

 ward, the movable jaw will follow because 

 of the spring pressure, thus eliminating all 

 loss of motion. There is only one objection 

 to this; that is, it fills up the space between 

 the jaws. When necessary the spring may 

 be easily removed. — W. Burr Bennett. 



Popular Science Monthly 



Spring in vise jaws 

 to hold them apart 



Making Large Fly Traps for 

 Packing Houses 



GETTING rid of flies in packing houses 

 is one of the problems which has 

 engaged the attention of the Bureau of 

 Entomology in cooperation with the Bureau 

 of Animal Industry of the Department of 

 Agriculture. An extensive investigation 

 of the various types 

 of fly traps used at 

 the establishments 

 where Federal meat 

 inspection is main- 

 tained has been 

 made. While there 

 has been much varia- 

 tion in the effective- 

 ness of different 

 types of traps, it has 

 been found that the 

 conical trap is most 

 efficient. One type 

 of mechanical trap 

 has been found par- 

 ticularly effective. 

 This trap is 24 in. 

 high, 18 in. in diameter with a cone 22 in. 

 high, by 18 in. in diameter at the base. 



The frame is constructed of four hoops. 

 Two of these hoops 18 in. in diameter are 



A cone within a cylin- 

 der, both of screen wire 



nailed together. They form the bottom 

 of the frame and the other two the top. 

 The top of the trap may be made of an 

 ordinary barrel end, with the bevel edge 

 trimmed off so that the head will fit closely 

 in the hoops. A 10-in. square is cut out 

 of the center of the top to form a door, 

 the portions of the top being held together 

 by 1 -in. strips placed around the opening 

 l /2 in. from the edge, to form a jamb for the 

 door. The door is a narrow frame covered 

 with a screen well fitted to the trap. 



The top is then nailed to the upper 

 hoops. The outer part of the trap is 

 formed by fastening fine mesh galvanized 

 screen wire to the outside of the hoops. 

 Four light strips are tacked to the hoops 

 on the outside of the trap to act as supports 

 between top and bottom hoops, and the 



Laying out a pattern, with an ordinary car- 

 penter's square, for cutting the cone wire mesh 



ends are allowed to project at the bottom 

 to form legs. The cone is cut from the 

 screen wire and may be either sewed with 

 wire or soldered where the edges meet. 

 The top of the cone is cut off to give an 

 opening 1 in. in diameter. The cone is 

 then inserted in the trap and tacked to the 

 hoop around the base. The fly trap is 

 now complete. 



In constructing the cone it is best to 

 cut a pattern from a piece of heavy paper. 

 An ordinary square is placed on the ma- 

 terial from which the pattern is cut. A 

 distance equal to the height of the cone 

 is laid off on one leg of the square and a 

 distance equal to one-half the diameter 

 of the base of the cone is laid on the other 

 leg. A line is then drawn between the 

 two points A — B. In order to figure the 

 distance around the base of a cone of any 

 given diameter, multiply the diameter by 

 3.1416, or 3 1/7. Cut out the pattern on 

 the curved line from C to D and on the 

 dotted lines from A to C and A to D. 



