sorry the pics are terrible but you should still be able to make them out. made this this evening using a drill press, welder, and a sawzall with a metal blade. 1 1/2 thin walled square tubing. #9 galvanized wire for the strap. a 20 penny nail for the dog. the bolt out the bottom is a 3/8 carriage bolt about 6 inches long.
the small hole is for the spring bolt. 3/8. the large hole is 5/8 with a nail tack welded. i flatened both sides of the nail with a hammer and anvil.
after bolting the spring on i bent the ends to the approx. angle shown. this takes quite abit of the pressure off.
drill 2 holes for the strap as shown.
bend the spring arms down and mark them where it meets the holes and bend them in a vise.
attach #9 wire to springs by wrapping.
this pic shows the trigger and a nail used for the dog. a small piece approx. 14 guage sheet metal is welded to the end off the tubing to attach the dog.
i also tack welded a #9 wire, bent to the same size as the tubing, to the end of the tube so i did not have to worry about the sharp end.
base plate and chain added. also 3/8 carraige bolt to spear the trap to the ground.
in the set position.