Primer mine

[Garbage]

I would like to know your opinion if this detonator could work in a mine.

http://www.angelfire.com/oz/garbagelive/mine/mine.jpg

[steyr]

It's better to do it with battery, and when you stand on it, battery connects with explosive and boom.
Your mine couldn't work in some ways, because you must stamp on it hard, or run on it.

[Sarevok]

If too much dirt gets in between the T-shaped piece and the mine, the nail wouldn't hit (or would hit weakly) the primer, I think. You could make instead the mine found on US Patent #4218974 (http://l2.espacenet.com/espacenet/viewer?PN=US4218974&CY=gb&LG=en&DB=EPD) (also found on NBK's pdf); its much cheaper, safer, simplier and functional.

[Sparky]

Yes, as people have said, the trigger mechanism is not up to snuff.

No point in trying to reinvent the wheel, you might as well just look at existing designs. Mines I have seen on howstuffworks.com often use a "button" configuration instead of a T shape. This way no dirt can prevent it from firing.

What is missing from your design is a bellville spring or at least some other mechanism to make sure the firing pin is coming down hard enough. Take a look at:
http://people.howstuffworks.com/landmine1.htm
for what a bellville spring is, not to mention the rest of the document about mines.

The electrical system might be a good idea, maybe easier than trying to get a belleville spring. The only thing I would be worried about is reliability - that is things like corrosion, when the mine gets rained on, the battery going dead etc. OTOH having an electrical system introduces the possibility of turning the mine off by remote. That's placing a lot of trust in your eletronics though.

[Garbage]

I solved the problem of the dirty with a plastic or metal cone:


http://www.angelfire.com/oz/garbagelive/mine/mine2.jpg

http://www.angelfire.com/oz/garbagelive/mine/mine2.1.jpg


With it the mine will stay sealed.

[Hang-Man]

I was thinking of making a much more sensitive mine, what I had in mind was letting AP crystallize amongst ball-bearings. If something disturbs the bearings, causing them to grind etc, BAM. It would need to be set up in advance, fill container with BBs, pour in hot acetone/AP solution, walk away, in a few hours the acetone will evaporate and the AP will form large (because it was hot) crystals between bearings.

[McGyver]

Is a shotgun primer really that sensitive? Try testing the primer by itself and tell us your results...

[Garbage]

I took the idea from a simple Vietcong booby trap:

http://www.angelfire.com/oz/garbagelive/mine/mine3.gif

If trod can activate it a vehicle could do it too.

I would like to test. but now in my country every thing is forbidden, guns, knifes, explosives (any kind). If I want to do it I have to make every piece of it…

[FragmentedSanity]

The primer should go off if enough pressure is put on it - your nail would tear through the primer which should cause detonation. You would want a compound detonator with a sensitive primary under the primer.
The design would be greatly improved by making the nail / firing pin spring loaded, using the pressure plate as a "trigger" - this would ensure detonation when tripped as you are basically recreating the conditions for firing the primer in a bullet.
Mechanically detonated mines have some advantages over electrically fired mines, like no batteries to go flat. It also has some drawbacks, like not being able to incorporate things like timers. It is really a matter of personal preference, and how you plan to deploy the device.
To test how easily the primers detonate you could just use a live round - as in the booby trap shown - with a weight dropped on it from above via a rope and pulley. Use several rounds to test things like how much weight you need and from what height it falls to reliably fire the round; if it will go off with a heavy wieght being slowly lowered onto it or if it actually takes a sharp impact. A few simple tests should answer all your questions - and give you some data you can share.
Ive often thought a mine that used primers as the fragments - instead of - or as well as BB's - would be interesting, probably not overly effective - but it would cause masses of sharp high velocity shrapnel - almost like mini fletchets.

[Cyclonite]

You should have the T part under spring tension, a small detent will hold the spring until someone comes along and gives it a little knock. Kinda like a mouse trap in a way. Also when doing this put a pin through the top of the T as a safety pin and tie a string to it. Go behind some cover and pull the pin gently out and its good to go.

[aXiate]

that should work, maybe if you had a more reliable way of detonation... such as the electronic one
that some people have already pointed out. but i supose if you lived on a farm and wanted to blow the neighbour off his tractor :D... then it migth work :)

[roux]

i think a plastic bag would work alright to keep dirt out of the trigger mechanism. i know it isnt the best solution to the problem, but it is the easiest.

[Serj05]

I think McGyver is right. a shotgun primer has a good chance of not going off under some weight. Also from what i see in your picture, it looks to me like the nail and primer may be too close to each other. Maybe if you spaced them farther apart the nail could build up more speed to set it off.

[SMAG 12B/E5]

Garbage, your system will function well if you take Cyclonite's suggestion and use a spring-driven firing pin. Make the firing pin separate from the pressure pin or plunger. Instead of a spring detent, use a copper shear pin. Pressure from the target to the plunger bearing on the firing pin shears the copper shear pin releasing the firing pin which is driven by spring energy into the percussion primer.
The Viet Cong "toe popper" often failed to fire. The VC filed the cartridge base and primer in order to reduce the primer thickness. This reduced the amount of force required to crush the primer.

[Cyclonite]

A shear pin would work well and be less hazardous but keep in mind this is improvised and a shear pin would be more likely to fail than a detent due to it not being the right thickness or someone that was a little to light and they dont break it..

[Skean Dhu]

Solution: while reading this thread, and hearing people tell you that to make it reliable you need the trigger to be under pressure from a spring i thought of a center punch. you could use the ones for making divots before you start drilling, glass punches for emrgency extraction/evacuation of a vehicle or any other readily availabe center punch for that matter.

EDIT: Spelling

[Garbage]

I have made some triggers for clay more mines some time ago:


http://www.roguesci.org/theforum/showthread.php?s=&threadid=3440


Both use the electrical system. They work better than the mechanicals in a short period of time. After some months the battery become to suffer corrosion. The electrical mines must be sealed to avoid water from rain (short circuit).
Here is some draws of two mines with string’s trigger, the first is electrical and de second uses the mechanical system.

http://www.angelfire.com/oz/garbagelive/mine/mine4.jpg

http://www.angelfire.com/oz/garbagelive/mine/mine4.1.jpg

http://www.angelfire.com/oz/thegarbage/trip/d2.jpg

I’m not sure in the second mine the nail with the string in the trigger will hit the primer. I haven’t tested it.

[torgo]

It seems like something like this would be mostly safe and functional, useful for theatrics and the like:

http://boom.godnatt.no/magic-show.jpg

A "safe" mode is obtained by either not arming the plunger or obstructing the lever. A mode requiring only a pin release would involve only transposing the spring to the other side of the lever.

[Jacks Complete]

torgo,

that is a great design!

As a safety feature, drill a hole in the nail, so you can put a pin/clip through it, then it can't go off by accident. Obstructing the lever I would not class as "safe"!

Also, try to find those nails that have a washer halfway along them, as that would make it easier to do.

Finally, make sure the angle of the release pin is NOT rounded slightly, like you show! This would likely cause it to slip! I am talking about the bit behind the arrow "2". The design you have drawn would likely be dangerous as the pin would bend over time, and even a tiny bend would cause it to fire. The pin should stay fairly straight.

OP, I would use a firearm primer rather than a shotgun one. Turn it upside down, and put the nail (bluntened) almost into it, then surround with explosive. This will ensure a crushing action, rather than piercing.

[Garbage]

It really works, I had some problems to keep the handspike fixed (silver tape). Don’t use a string too strong or the nail will escape from the handspike.

http://www.angelfire.com/oz/garbagelive/mine/mine5-1.jpg

http://www.angelfire.com/oz/garbagelive/mine/mine5.jpg

This trigger is very sensible but is much better for the mine.

[Fergus]

The problem with the viet cong toe popper is that it has no barrel to build up compression for the bullet to do any harm. We tried making them in the army and at best all we got was a muffled pop and no real danger to the person stepping on them.

[Jacks Complete]

Fergus,

Might I suggest hammering the bullet back into the case a bit then? The pressure goes up dramatically if you do that, so the whole round might just blow up, causing more damage than otherwise.

In ammo, the overall length is strictly observed, as if it is too short, the pressure in the round increases dramatically, and the breach can blow!

[zeocrash]

while working on my smoke grenades i decided to experiment with smoke mines, the principle for my detonator was simple, a phial full of pottasium permanganate was placed in a bag with glycerine. in the top of the mine was a nail. the phial was positioned directly under the nail. when someone trod on the mine the nail would be pushed down breaking the phial and mixing the permanagante and glycerine, causing the mixture to ignite. This is somewhat slow for a landmine, but a similar method could be done using conc sulphuric acid and chlorate or similar

[Baughb]

Another idea for an firing device would be to have the central plunger's core drilled through, so that when you step on it, it allows a spring-driven spike to fire the primer. It seems a good bit simpler than a lot of designs posted so far, and is easily adjustable for various trigger pressures. A simple design would be something along the lines of the following.

_________________ - pressure plate
| |
| |
______) (______
|===*| | @
-------- --------
Where the )( area is the hole bored through the rod, = denotes the spring, and * is the firing pin, and @ is the primer.

When the pressure plate is stepped on, the hole in the rod is forced down to the firing position, which allows the coiled spring to expand to normal length, driving the firing pin through the hole and impacting the primer.

A spring could be added under the pressure plate with enough forces to return it to the default 'at rest' position, if desired, and a safety pin added underneath the plate to prevent accidental triggering while in storage or during placement. The design can also be made remarkably compact, and by using a spring of sufficient force the primer will fire quite reliably. It also conforms to the KISS rule, I believe.

[lumberjak5010]

In central america during the eighties, we found mines constructed much like the vietnamese type posted by Garbage. These mines were of the same concept, but used an artillery shell sitting in a coffee can or a larger, empty shell casing. In the bottom of the can, a piece of round plate steel was placed. In the center, there was a piece of hardened rod, ground to a point and welded into place. A certain size of rubber hose was cut to a length just slightly longer than the "pin" to support the weight of the shell. Stepping on the shell would collapse the rubber hose "grommet". and cause detenation. The artillery shell projectile was cut off flat and deeply fluted lengthwise. Atop the flattened portion of the projectile was another piece of plate steel, also deeply fluted in a hex pattern, several feet square with about a 1/8" hole in the center. A screw held it to the center of the projectile. The shell was placed in the can with two or three soda cans shaped in a cresent to hold the shell in the center. Around the entire device, they usually packed vegetation to keep is stationary. On top of the fluted plate, they taped nasty screws and nails and heaps of broken glass or gravel in a mound. These additional projectiles were often dipped in a compound of some sort, (I can't remember what it was) that made you very sick or killed you after the projectile penetrated your skin. Some of the guys told me that if the mine was fresh, that you could smell the toxin the nails had on them. I noticed the mine was usually an inch or so below the trail surface, covered with burlap and dirt. It was a devastating mine. We thought initially that it was primarily an anti-vehicle mine due to the power it had. However, that depended on the shell caliber, etc. Many of the mines were later found on trails too narrow for vehicles. So, they must have also been intended to be anti-personnel. Hope I didn't break any rules for my first time.

[Jacks Complete]

lumberjak5010,

not at all, that was a good first post!


Ok, a nice theoretical design:

I have thought about this a bit, and my conclusion is that an explosive "automatic" centerpunch would work really well. Take a piece of steel bar, drill a hole in the end of it the diameter of the rod you want to use. Cut that rod to the depth of the hole, plus whatever you want to use as a spike to face upwards. Check it slides nicely, you want it like a piston.

Work out where halfway is, and drill a hole that far down for your safety pin.

Take the primary of your choice. Put some in the bottom of the hole. Carefully slide your piston down to halfway from the bottom (obviously being careful not to hit your primary!) and hot glue or melt wax around the piston part. Do this whilst it is still on its side, as even with a close fit you don't want to risk any getting inside the piston. Turn it over on the long axis, and seal the other side. Give it a tug to make sure it is sealed tight.

Set into a small hole, pointed end up, and remove the pin. The force of a foot on it should shear the wax and force the piston onto the primary, crushing it and causing an explosion which drives the piston up into the foot of the victim.

Any thoughts? I am not expert on primaries and the usage of.

A variation would be to use a primer or two. How hard can you crush one without to going pop? Would it be reliable?

[Dave the Rave]

Yes Lumberjak, good 1st post ! the newbies can learn from you.

On top of the fluted plate, they taped nasty screws and nails and heaps of broken glass or gravel in a mound. These additional projectiles were often dipped in a compound of some sort, (I can't remember what it was) that made you very sick or killed you after the projectile penetrated your skin. Some of the guys told me that if the mine was fresh, that you could smell the toxin the nails had on them.

The nasty toxin was only pig or human manure, maybe some blood, which mixed with the shit becomes some nice and good spot to tetanus and ads some sticky abilities to the putty. The smell was stronger when it was fresh, but when it grows old, it becomes less powerfull.

All of those kinds of mines are intended to Anti-personnel use, and only some can disable an motorcicle or an light vehicle.

By the way, where are you from ?