Key Chain Jump Trap

Before printing make sure you have a couple of round toothpicks available for the axle pivot shafts. The ones I used were 2mm in diameter so any small stick about that size should work. Larger ones could work if you drill out the holes.

This was developed and printed with ABS. If you use a different material please post a note about how your version turned out.

Printing

Print the Jump_Trap_Parts file without support. There are support structures already placed under the overhang pocket that the spring slides into. I found these supports were easier to remove than the support that resulted from turning on support in the slicer.

The Jump_Trap_Spring file will need support turned on for printing. If there are adhesion problems when printing the spring, add about 5mm of brim around the base.

I used 0.25mm for the Z-step, 20% fill and sliced with 1mm of plastic for the top and side shells.

Assembly

Use your jackknife to remove the supports under the spring holder overhang in the base. Also the top of the side “bearings” may need cleaning out if you printer doesn’t do bridges well.

Snap the jaws into the “bearings” and make sure the move freely. You’ll need to remove them before installing the spring.

Slide the spring into the slot in the base. It should be a snug fit.

While holding the pan pivot hole aligned with holes in the center support, slide a toothpick through the holes and trim off the excess with your jackknife.

Do the same with the toggle pin while making sure that the flat side (with the bump) will be up so it can mesh with the notch in the pan.

A drop of CA glue on the ends of the toothpick axles will keep them from working out.

Now while pressing down on the spring, slide one end of the jaw axle into the bearing hole in the base. Squeezing the jaw, slide the other axle into the bearing on the other side of the base. Repeat with the other jaw. I aligned the jaws so that the smooth side from printing was down (i.e. to the outside where it contacts the spring) since I thought that produced a smoother trip action.