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TM 31-210
Improvised Munitions Handbook


Section VII

No. 7

KNIFE SWITCH

This device will close the firing circuit charges, mines, and booby traps when the trip wire is pulled or cut.

 

MATERIALS REQUIRED:
Knife or hack saw blade Sturdy wooden board.
6 nails Wire
String string or light rope

PROCEDURE:
1. Place knife on board. Drive 2 nails into board on each side of knife handle so knife is held in place.
2. Drive one nail into board so that it touches blade of knife near the point.
3. Attach rope to knife. Place rope across path. Apply tension to rope, pulling knife blade away from nail slightly. Tie rope to tree, bush, or stake.
4. Drive another nail into board near the tip of the knife blade as shown below. Connect the two nails with a piece of conducting wire. Nail should be positioned so that it will contact the second nail when blade is pulled about 1 inch (2-1/2 cm) to the side.

NOTE: Check position of nails to knife blade. The nails should be placed so that the knife blade will contact either one when the rope is pulled or released.

HOW TO USE:
Attach one wire from firing circuit to one of the nails and the other to the knife blade. The circuit will be completed when the tripcord is pulled or released.


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