Instant Caltrops





Introduction: Instant Caltrops

About: Tim Anderson is the author of the "Heirloom Technology" column in Make Magazine. He is co-founder of, manufacturers of "3D Printer" output devices. His detailed drawings of traditional Pacific...

In this instructable I'm going to teach you how to make your own caltrops.

Caltrops are an ancient weapon like a metal sandburr. It's a nail with multiple points that has at least one point upward no matter how it lands. They are also called "star nails". This is the quickest way to make them.

Some people consider caltrops a political weapon in this era of wars for oil for vehicle fuel.
If you are such a person you should pursue your ends by peaceful means instead.
Remember Noam Chomsky's advice:
"If you fear the government the proper response is to get more involved in government, rather than less so, because the Government really is the institution that represents you."
Watch the movie "Weather Underground" to find out what some famous political vandals wish they'd done instead.
I think it was Bill Clinton who said, "It's best to conclude that bad policy is caused by ignorance, not malice."

Safety Warnings:
Flying sharp metal will hit you in the eye.
If someone steps on one of these they'll get hurt.

Excellent photos by theinfonaut

Step 1: Nicaraguan Caltrop

Caltrops in the Gallery of Heroes and Martyrs in the town of Masaya, Nicaragua.
These look like barbed wire barbs cut off and welded together, but they're much larger than any barbed wire I've seen. These were used in the revolution against Somoza in the late 70's. Nicaraguans threw them onto roads in front of troop truck convoys to delay them with flat tires.
Somoza was a ( yawn, yet another ) U.S. supported brutal dictator.

By the way, a recent issue of Time magazine reported that Nicaragua now has the lowest risk of terrorism in the hemisphere.

Step 2: Chicken Wire Ain't Chicken No More

Cut off some cross-shaped chunks from the chicken wire using a bolt cutter.
Then cut the ends off again at an angle to make them sharp. Watch out for flying bits of sharp metal hitting you in the eye.

Step 3: A Tripod and a Spike

Bend the sharp wires as shown. You're done!

Be super careful with these nasty things and don't leave them lying around.
These are only to carry in your pouch at the renaissance festival as part of your costume.



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    74 Discussions

    Just bend two fencing nails out to a 90 degree angle, then tack-weld them together!

    I'm sure you know what you're talking about, but I'd say that most people would call it chicken wire.

    At the risk of sounding like a smart-ass, I feel compelled to mention that no one who had ever kept chickens or knew anything about them would call that chicken wire, since it obviously wouldn't work to keep chickens in. Most people who buy or use it call it galvanized fencing, "welded wire," or "hog wire" -- though real hogwire is wrapped, not welded. Most 2x4 wire is used for staking tomato or bean plants, or for keeping idle chompers out of your garden. Baby chicks, or even small banty chickens, would walk right thru this 2x4-inch mesh. As Lokisgodhi points out, you need to ask for the right thing in order to get what you want. The wrapping on these should be done tightly, since more than likely the cheap spotwelds on 2x4 welded wire will probably break somewhere during this process. Homemade caltrops are often made by epoxying four shingle nails together at their heads, as some vets may recall. The OSS made caltrops for use by resistance forces, and issued instructions for making your own from wire or nails as a field expedient to disrupt Nazi transportation.

    Your completely right. It is referred to as welded wire or galvanized fencing not even close to "chicken wire"

    I have been dealing with wire mesh for a long time.. If you really want to see the variations on wire mesh fencing, inclucing chicken wire and welded wire, galvanized and all the size and mesh variations.. you can check or

    Not even the same style as chicken wire. Two totally different products hero.

    If you're ordering chicken wire with the expectation of making these, then you're going to be disappointed with what arrives.

    Huge "bump", but you're right - that's not chicken wire. I don't know what these people are talking about.

    "Warning: Some people consider caltrops a political weapon in this era of wars for oil for vehicle fuel. If you are such a person you should pursue your ends by peaceful means instead." It would seem to me that anyone using these for such a purpose would also want to weigh up this 1) Will cause the car owner to go and purchase a new tyre - more consumption. Although I guess the tyre could be easily repaired 2)If more than one tyre is pucntured it would mandate a pickup truck call-out, more gas consumption 3)Very unlikely to change the car owners mind about the use of their car. A more effective method are those stickers "did you know your SUV is causing global warming"

    5 replies

    this guy should really learn how to spell the word "tire" in the correct fashion, it isnt hard, just think (referring to radiorental)

    Poor Sonaps is the one who needs spelling lessons. In standard international English, "tyre" is a noun describing the external part of a wheel which comes into contact with a road surface whilst "tire" is a verb relating to physical fatigue.

    It is quite telling when someone with limited exposure to a language insists that correct usage and spelling be replaced by their simplified version. Learn something about the world Sonaps - get a passport and visit some English speaking countries (ones that would never elect a Trump, Reagan or GW Bush).

    You're assuming that the person will care about your opinion beyond the fact that they are inconvenienced by having to remove the sticker from their vehicle. That's probably unlikely to be the case.

    Caltrops are minimally destructive device and will cost significantly longer in money and time to repair or replace the tire. They're non lethal assuming one isn't moving at a high rate of speed when you hit it.

    The last, more extreme option would be to devise a catastrophic or lethal device, like a cable strung across a thoroughfare or and IED.