BIOLOGICAL SURVEY BEAVEB TRAP 6 



Heat and turn up ends of base bar at right angles, 5 inches from 

 ends, then heat and make a short quarter twist 2 inches from tips of 

 iurned-up ends, and thin the inner edge of twisted section to one- 

 eighth inch thick where it comes between trap jaws, to keep them 

 from passing the center. 



Heat and turn up at right angles the ends of long cross bar, 2 

 inches from tips. 



Heat and round and turn out at right angles 2-inch tips on each 

 end of the two flat steel bars for jaws, to fit the holes at the ends of 

 the base bar. In rounding the ends of the jaw strips the tapering 

 should be on the outer edge, so that the tips may be almost in line 

 with the inner edge. 



Wrap No. 3 wire for coil springs 1234 times closely around a 1J^- 

 inch iron pipe or hardwood rod, leaving one end about 16 and the 

 other about 14 inches long, with the two ends at right angles when 

 open and free. The springs will unwind one full turn when released, 

 leaving 1134 turns. Heat and bend the tips of free ends of springs 

 to form hooks to clasp the jaws when crossed. 



Bend the 24-inch No. 6 wire in form of hairpin, for the trigger 

 spring, about 10 inches long and 3 inches wide at the open end. 



Bend 1-inch loop in one end of each of two 10-inch No. 6 wires, 

 for trigger bars. 



ASSEMBLING THE PARTS 



Bolt longest cross bar at right angles under base bar with the 13- 

 inch cross bar above, with a 1-inch bolt through center and two %- 

 inch bolts through holes in ends of 13-inch bar and corresponding 

 holes in long cross bar. 



Fasten the two 11-inch short cross bars across top of base bar, 

 with a M-inch bolt through the middle of each and through the hole 

 8 inches from the upright ends, to support bottom of trap. 



Slip coil spring over bent-up ends of base bar until below right- 

 angle bend, with shortest arm next to jaws. 



Bend jaws in a depressed semicircle around wooden form so that 

 they will fit together when in place and reach just inside of bent-up 

 tips of cross bar when open. 



Spring bent-up tips of jaws into holes in turned-up ends of base 

 bar, and make all necessary corrections of curving so that jaws will 

 fit together. 



Clasp shorter end of spring on one jaw, and use pressure to bring 

 the longer end across to clasp the other jaw in an upright position. 



Weave 3-inch half-hitch loops of No. 15 wire through holes drilled 

 ■3 inches apart in the trap jaws, the loops outward, and twist the 

 clasping parts down tight to jaws. 



Hook the 1-inch loop at one end of each of the 10-inch No. 6 steel- 

 wire trigger bars downward into holes at ends of main cross bar, and 

 close up loops so they work freely. 



Rivet the two small brass hinges at the holes 8 and 9 inches from 

 ends of main cross bars, so that the free ends will stand upright 

 about 7 inches from the turned-up ends of bars. A small hole 

 should be first punched or drilled near the middle of the free part 

 of each hinge, and the terminal screw hole enlarged to form a loop 

 that will admit the tip of the trigger bar loosely. 



Make the trigger of No. 12 galvanized wire, bent in the middle 

 into a 2-inch circle, with downward projections one-fourth inch 



