For a while it's been bouncing around in my head the idea of a screw.

Not THAT kind of screw <img border="0" title="" alt="[Wink]" src="wink.gif" /> , nor the common type find at the hardware store, but rather a VERY large screw made of a lightweight, but tough plastic, that has a very narrow tip to fit into a small hole made in security glass or between burglar bars.

This screw (shaped like a plumb bob) is only a couple of feet long, and has a large hard steel spiral thread built into the steel sheathing on the outside of the plastic core. On the back end is a ratchet mechanism for turning it that has a large lever attached to it.

As it's turned, it pulls itself into whatever it's threaded into, expanding the hole/bars, using the force mulipliers of the inclined plane and the lever.

Once it was in as far as you could turn it, out comes the sledge hammer. :)

Whack...whack...whack...in it goes.

Once it's in far enough (the largest part of the screw would be equal to a hole big enough for you to crawl through), you'd slide the bar to the other side and give it a whack to work it loose. Now you're in. :D

Brilliant idea? Or stupid?

The idea itself is certainly something to think about.. but there are definetly some rather obvious drawbacks for the uses you have forementioned.

(1) to use it to pry open prison bars... well the bars that I have seen locally are about 3-4 inches apart.. for a 'screw' to fit this it would have to be at least as wide in diameter as the bar spacing. And I don't guess you are going to sneak something 2ft X 6 inches long into a prison without someone questioning

(2) to use it in security glass would be probably even more difficult.. security glass usualy has a 'break-in' detector that goes off when the glass is cracked... a screw of anysize would definetly break it

i think i get the idea, but i really don't see the point of it.

maybe i missed something...

Sounds like a really good idea to me. Quieter than sawing the bars, apart from maybe the sledgehammer bit... Remember to take some oil with you too :)

Just a little something I whipped up to illustrate the idea.

<img src="http://server3001.freeyellow.com/nbk2000/Screw.gif" alt=" - " />

When being used, there's an extendable metal post (red) that acts as a pivot to support the screw while you turn it, otherwise it'd wobble out.

The main use (in my mind) would be to enlarge a small hole (bullet/drill) through security glass. It'd crush the glass and pull any laminated film away, leaving a nice hole for you.

What material would the "screw" be made out of? And would it be differant materials for "drilling" into differant material?

plastic? really? I don't think this would work too well in situations where you've got to haul ass, but if you've got the time, why not?
Interesting idea NBK, but how would you manufacture this beast?
Being somewhat of a machinist, I can tell you that it is impractical to try to machine this, unless you've got access to CNC, and an injection mold for this thing would be a masterpeice in itself.

You could bend a bar into the "thread" shape and then weld it to a steel cone, or you could simply make a casting of the shape. A foam blank of the screw wouldn't be too hard to make using a hot-wire cutter, or even a craft knife. Then it's a matter of having something with which you can melt steel.

The cone is made from thick gauge steel rolled and lap welded with a small opening at the point. The round spiral "screw" is then welded on and a small steel cone tip is welded on the end of the cone with the ratchet rod mechanism welded to it with a steel rod down the center of the cone.

The body is then filled with a turned polyproplyene plastic foam cone pressed in under great pressure for strength.

Simple, as long as you have access to a machine shop. Which anyone with some decent money can buy. :)

That picture... It looks like someone's stealing christmas :) .

And you are planning on this 'product' to have the ability to break through prison cells?

HAHA.. (still laughing at pyro500)

maybe i dont have my mechanical advantage thinking cap on the right way, but isnt the effort involved in screwing a screw directly (or even at the square) porportional to the 'steepness' of the threading? ie the faster the screw increases in diameter, the less emchanical advantage you have... if you wanted something to pry burgler bars apart it would have to be just plain old silly long to be of any use..

although it might be a good way to pry glass windows out... i have seen windows that dont have any structural device holding them in place, just cauking... if you got the screw in there and pulled you might be able to yank the pane (with the help of a razor knife) without breaking it...

I would like to suggest the employment of taper closer to 15-20 degrees. It will give you a better MA as mention above. It will also be eaier to start.

A question about you design; Is it a one size fits all? or do you plan of adjust you taper, threads per inch(TPI) and depth of thread depending on the application(Material).

How about placing the screw in a barrel/tube which the widest part screws into. Then propel it by a gas producing composition, so that it will start to rotate quickly. I don't know if it's clear what I'm saying here, but basically think of a screw like slow bullet.

Who mentioned anything about prison? :confused:

It's just an idea folks...even Da Vinci had a few "bombs" (pardon the pun <img border="0" title="" alt="[Wink]" src="wink.gif" /> ).

Anyhows, the steeper the thread, the less the mechanical advantage. This is because the length of the inclined plane is shorter, requiring more effort.

The idea behind this would be a simple device that could be used to break through a cinderblock wall with rebar reinforcment, without the sound of hammers smashing concrete or power drills.

The screw would pull itself into a small pilot hole drilled by hand and, as it goes in, crushes the concrete and spreads the rebar, until the hole was big enough to slip a small child in (they are good for something after all! :D ) to unlock the doors or turn off the alarms.

You'd use a deadblow sledge (rubber with lead shot inside) for whacking the lever, so there's practically no sound.

It's a tradeoff of time against stealth. You'll take an hour to quietly get through the wall with a screw, rather than 10 seconds to blast through it with explosives.

NBK how about mounting a huge one of these units on a hole driller on skid-steer(bobcat) for breaking through walls and the like?

Sounds like a great place to use the Fake dumpster I heard someone talking about...

Maybe that was a different forum :rolleyes:

It was on the Lock Down! forum, topic made by NBK.

- My mistake.

<small>[ November 11, 2002, 07:37 PM: Message edited by: Eliteforum ]</small>

a-bomb... if your plans call for a bobcat i think at that point you might as well just stick with blasting your way through :)

BZZZZ!

The dumpster hide was on Lockdown!, not here.

True about the bobcat...if you're using that, just blast a hole through the wall, it'll be much quicker.

Why not use a modified car jack to do this or create something of the same idea. Instead of driving a screw straight in, insert the jack which would unilize a screw in the prependicular direction of the other method taking up much less space and would be easier to carry&gt; Of course this would not work for enlarging small holes and such&lt; but for pyring open bars it should work well&gt; I just fucked up my keyboard and I cant figure out how to fix it right now without rebooting so sorry for the lack of grammer and &gt; wherever there should be a period&gt;

Seeing how size is pretty crucial here and amount of torque applied should be maximum, maybe a couple gears attached to it then handle on the other side of the gears some how. Maybe a small gearbox like a like a steering box off a car or something like that. This would make the speed of the drill much slower but the torque would be much higher. The handle for this could be round too, maybe the diameter of the end of the screw or something. Ah ha! Another idea, if it is possible to have the inside of this large screw hollow, the gearbox could be located inside to minimize size.

Another idea to increase breaking power is a telescoping handle. Like one that can be extended so you have more leverage.

Im thinking that perhaps a device akin to a big pair of scissors with a hydraulic jack at the end your fingers would normally fit in. If you placed the hinge close to the spreading bars and had nice long bars extending to the jack itself then you could widen holes very easily in concrete and probably bypass rebar as well because of the multi-ton force exerted by a small hydraulic jack.

Using this to get through thick walls would be better too because the screw will be very hard to turn if say you are going through a wall that is 1 foot thick...plus with a steep thread the hole you make on the other side of the wall from where you are drilling will be small still unless the screw is very thick.

Either way...I think a device named 'The Screw' is pretty freakin awesome sounding.

IMO, a spreder will not work, as you are trying to slide the wall either side along the ground and split it up the middle. It's going to be higher resistant to this kind of stress. It's almost akin to trying to destroy the wall by pilling weight on top of it to try and collapse it.

The Screw *pulls* the wall material forwards - it's loading the wall in the fashion to which it is weakest.

That said, it's going to take a hell of a lot of torque to use this thing effectively and if the device is strong enough, the operator probbaly wouldn't be...

Well, even if the screw is impractical for breaking the concrete itself, it could still be useful for spreading the rebar once the concrete has been shattered with explosives.

Rebar is usually left intact after an explosive attack, requiring that each individual rebar be cut. This takes time.

But, if they could be simply bent out of the way, this should greatly decrease the time it takes to clear a path through the breach. And there'd be no jagged ends of cut rebar for you to get cut up on. :)

What about a power drill, a gearbox, and a car jack?

Quick, powerful, and presumably effective.

I recently had an occasion to test "The Screw", but on a much smaller scale, and not to get into a place, but to keep someone out of a place I was in.

See, you can use a long wood screw, and screw it into the gap between a door and the frame, and it acts like a locking wedge, because the increasing diameter of the screw forces the door against the jamb (on the other side from the screw) and the screw threads cut into the wood, making linear motion (opening the door) [nearly] impossible.

I was somewhere where I didn't want someone sneaking up on me through a door with a high window and no glass (small enough they couldn't climb through, but could
reach in and open it), so I used a 2" wood screw in the above manner to 'cover my six', and, later, someone DID try to get in, but the screw kept the door shut, even though they tried kicking the door open. :p

Mind you, the screw is just in the gap, and NOT through the door and into the jamb, so it's easy to do with the screwdriver in a pocket tool, such as I used, no power tools needed. And, more importantly, you're not trapped by something irrevocable (or time-consuming) if you need to get out of somewhere in a hurry.

I'd imagine a strong torque screwdriver with a stainless steel screw could be used with metal doors/jambs for the same purpose.

There are 'security' screws that use various types of heads so common tools can't undo them, only special bits, so that'd be the ones to use, so no one else could undo them within any time to do them any good.

Just the thing for shaping the urban battlefield to your advantage and thwarting piggy creeping. :p

Concrete? Use a hand drill and masonary bits to drill holes for the placement of Dexpan http://www.archerusa.com/Product_Dexpan_En2.html
It slowly expands silently to the efect of popping out an entire doorway to walk thru.

Interesting trick.

A similar one would be using a wedge behind the door, except that wedges allow the door to open a little first.

As for the original idea, well, that could be interesting. If it was a cutting type of thread, a self-tapper, then it would be quite interesting, but I agree with the others who have said that the torque would be too high. You are trying to crush concrete or brick, and that isn't easy.

I've been thinking about a neat way of getting through walls, though. Think of a kind of automatic center punch, but, instead of being 6mm thick, make it 4 inches or so. The design is the same, but scaled up, and the spring can be cocked beforehand. The body is quite heavy, and the actual punch is relatively light.

Walk up to brick wall, place point in center of brick, *ping*, brick is shattered.

Then you can use something like the screw, or a sprung steel strip with a towrope or winch, and pull the wall out.

Wedges can also be easily removed from their side, and aren't tiny like screws, nor are they silent to install like a screw, as you've got to knock them in to keep them from sliding.

If your looking for a fast way to put a good sized hole through a brick wall then u could try using a large metal spear made of a pipe and four thick pieces of metal cut and welded into a spear tip. This whole device could be placed into a truck bed and apon arrival hook it up onto the hitch system. Then just smash into the wall. You lose stealth but have you ever tried to crack brick. Its not very quiet defenatly something that would be noticed by bystanders or guards. And if you thought about grinding the brick with the screw then the length of this would be quite long.

New idea u take the mounting system of the above set up and instead attach a screw system attached to a 5hp motor. If you use it in a high traffic area or have a truck with glass packs or loud exhaust that should cover the noise of the 5hp engine. I know that they have enough torque and you could gear it to a just the amount for the job. Or you could try using a pedal bike hooked up to the same system. You would have the weight of the truck to hold the screw up and all the torque you need.This would still be a lengthy job and it probrably would be easier to find an alternative route or use explosives.

If you use it in a high traffic area or have a truck with glass packs or loud exhaust that should cover the noise of the 5hp engine.
That's sort of like covering the report of a rifle by setting off explosives, now, isn't it?
Or you could try using a pedal bike hooked up to the same system.
You're getting better at being quiet. I'm really laughing at the thought of anyone pedalling a bicycle attachment to drill thru a wall quietly and un-noticed, though. The piggies will be laughing when they see you, too. Laughing hard enough for you to make your escape in the truck with the glass packed muffler setup you spent so much money on. It should be equipped with outriggers, too, to keep the truck from swaying back and forth while you're on the bike-drill. :rolleyes:

A slightly better idea (and I really mean only slightly) in addition to your using a truck and a hitch attachment would be to have a hydraulic pump power take off (much like dump trucks use to tilt the bed) to forcibly punch holes in the brick structure with a hydraulic piston and wedge attachment. Again, this would not be a very quiet approach, nor stealthy. But all of the parts could be bought for under $350 (less than a glass packed muffler system). Even if it didn't work out the way you'd hoped... you can always make that log-splittler you've always wanted, and sell your bicycle powered log-splitter on E-bay. :D Might save you some whiplash, too.

Why not use the Hydraulics to "Turn" the screw?

My "71" GMC 1 ton has a hydraulic lift gate that will lift 1000#. The pump is 12V DC and can be adjusted to about 2500 psi. Attach a Hydraulic "motor" to the screw and the 12V pump to turn the motor. Mount the thing in the back of a Van, pull up along side the wall and open the side door. Have the thing on a rail system, slide it out to the wall and turn on the pump. You could apply preassure to move it forward with a bottle jack pump. The hydraulic pump shouldn't be any louder than the sound of the concrete block breaking apart. This would surely apply more force to the screw than a person could.

Just a thought.

Just took a look at the Dexpan link. Seems like a great idea for terrorists! Drill a small hole, pack it with goo, and leave. Two days later, down comes the wall, bridge, whatever. If you drilled the hole chemically, so it was silent too, it could be great for taking down infrastructure almost anywhere!

NBK, I didn't mean that the wedges needed to be banged in. They are faster to remove if you need to leave, and you can place them at the bottom silently by pushing them into place with your foot. It isn't limited by the size of the gap in the door frame either, which would be an issue if the door was a poor fit (more than .25" would be too much for a screw, wouldn't it?)

Another trick is to take the handle apart, removing the through bar. This will let you open the door with a screwdriver from one side, but the handle blocks the way, and the door looks totally normal from the other side. Probably not as strong as the screw in the frame idea, though. And there is nothing stopping you from using two or more screws.

I don' t think that Dexpan works quite like you guys are thinking it does. It appears to need multiple holes drilled and I dont think the average terr would be able to drill several 4 foot by 1 foot holes without any one noticing.

Dexpan requires at least 8 hours, or more, to begin fracturing the target material, depending on the number of holes drilled/spacing/size/temperature/etc.

It requires time, but it is capable of fracturing anything from granite to double-reinforced high pressure concrete. :)

Making the holes in a stealthy manner would be the problem for covert destruction, but all this is veering off topic, eh?

The Screw would require a ton of torque, but i'm thinking large ratcheting "cheater bar". A hole big enough for a smallish person to fit through would only need to be about 1 1/2 or 2 feet wide, how long would the cheater need to be with a given thread pitch to get a high enough mechanical advantage to grind through concrete? And since we're talking about many hours to get through anyways, I don't think that the ratcheting cheater would be overly noisy for stealth purposes. Just imagine walking by and seeing a man standing there furiously jacking a bar that's driving a screw into a wall. Suspicious? nawww!:rolleyes:

One modification to the idea: step the cone. This would (depending on the width of the wall) force one or two steps of the screw through at a time at most, while the landings in between coned sections would provide a grip for the next coned section to force through. Just a think I thought.

Just going back to spreading the rebar apart, do the American emergency services have the "Jaws of Life"? Surely you guys do.

Maybe something like that for spreading rebar, or cracking a wall?

Have a look at this (http://en.wikipedia.org/wiki/Jaws_of_life).

Maybe something useful there for the screw. A simple steel frame and the hydraulic ram to turn screw. It wouldn't be too hard to either carry there (with a partner or two) or to assemble on the spot.

There's no reason why you couldn't make an arm sized hole a lot bigger fast with a simple portable hydraulic jack. A 5 tonne jack with a chisel tip on one end would crack through concrete no trouble, and do it pretty quickly and quietly too. Just pop it in the hole and crank, and it will drive the chisel upwards.

Against security bars, you wouldn't want a chisel but a U shaped bit to ensure the system didn't slip out. However, pulling would generally be better and safer than pushing, and one of those 5 tonne ratchet straps might well be the answer - 5 tonnes far exceeds what any person could pull bare handed.

nbk, have you thought of marketing this as a poor man's "jaws of life" rescue tool? I bet many third world countries that cannot afford a JoL would jump on this. It could be used in building collapses to support or lift concrete slabs, or even break them up.

I doubt there are many countries that couldn't afford a set of Jaws. Whether they can be bothered buying them is a different matter, however. Generally the government are too busy trying to keep control and hide the money to buy rescue equipment, no matter how cheap. They manage to buy plenty of armoured limo's though.

I have seen too many countries that believe in "feeding" bullets to unruly hungery people. I have even seen it here in the US.

A small fire department in a city of some small nation would be interested in it for that very reason - no money for JoL.

The lever's force could probably be multiplied by using planetary gears to give more mechanical advantage. The central hub that the lever works on transfers the force to the planetary gears, which turn and reduce the angular distance that the cone travels, increasing the advantage.

The one disadvantage to using a cone that I can see is friction. A hard steel liner in the channel bottom with lots of lube would help. The slight give of plastic would increase the work required due to deformation. Aluminum may be better, but I am not a mechanical engineer.

I've seen your topic and remembered some of my classes in materials dilatation. While the teacher was talking about this, he said that the forces generated while a material dilatates and is pressed by another material are absolutely huge, and he showed some pictures of railroads that had bad projects and the spacing between the rails. The whole track was like a rubber stick while pressed by the poles! :)
So I've remembered another thing that may be useful in your works. Maybe if you drill a hole in the target, get one of those resistors used in electric ovens (see how much they dilate) and plug it in a power source (perhaps a battery) it will brake rigid materials with almost no noise of the machine, just of the target breaking. I'm not sure if this really can be used in practical manners, but I guess it needs just a way of having the electricity pass through (making a small hole to use a wire and at the side another for the resistance).

You could shatter something hard and brittle like that, yes, but there are many factors. You can shatter glass with a blowtorch and water far more easily and quietly than you can do it with a knife (almost impossible) or a set of boltcroppers. You can then chase the cracks in the direction you want to go with nearly no noise at all. Concrete spalls when heated as the water inside it expands faster than the pressure can release, causing bits to go flying.

However, steel and any other metal won't succumb to this type of attack unless you use a cutting torch to melt it away.

As already mentioned a big planetary gear will give enough power to crush almost any material.

But you'll need to drill first a hole completely through the wall with a guiding rod ;)

So first you'll drill let's say a one inch hole through the whole wall, then push in the driving rod with a peg like mechanism, to secure it tightly on the other side of the wall.

Put the conic "screw" on it and start cranking ;)

It's sure that the guiding rod has threads too which will fit into the threads in the hole of the cone. ;)

But honestly I doubt it'll be noiseless ...

Thinking about the expanding stuff it's always difficult to seal the holes a way all the pressure wont simply spill the stuff outside.

But a fast and quick way to crack would be several tiny holes filled with dry ice, some water and a good sealing.

But when it's a simple in and out immediately operation I would use just shaped charges to blow me a nice armoured concrete door

I mean the ones used for demolition of steel in buildings.

Simply selfmade, just buy copper L-profiles and U-profiles, fill in whatever you have as pyro an push the Ls into the Us to form a shaped charge building a line ;)

Put four onto the wall with duct tape, go around the corner and ignite the charges ...

If you want to be sure to get in and out quickly just drill some pegs in the upper part of the wall (beneath the upmost shaped charge) and wire them to the ground with a winch ;)

Whilst researching some safe cracking exploits I found out that the early safes were generally beaten by nothing more than some steel wedges and sledge hammers. A wedge would be hammered into a gap on the door, and then another, then long prybars and sledgehammering on the wedges would eventually cause the door to shear from the mounts, which were generally bolts into the door face that held the inside on!

If it will work for steel and the special high pressure concretes used in safes, it will work for regular concrete just fine.

I know that a standard sledge will do a great job breaking a concrete slab, and rather quieter than you would think, too. My dad taught me many years ago that there was a knack to it, though. I didn't break up much of the slab, but he blew it to bits in a lot less time, with just some effort and the knack. Sadly, I can't enlighten, since I never worked out how he did it!

As regards ways to turn a giant screw, you could try the bolt drivers that the railways use. Two big men hold them, and then drill a hole through the railway sleeper and into the floor with a huge squareheaded coach bolt. Apprently the torque is set before they start, and it's normal to hold it at about 150 ft-lbs, but it goes up to something daft which causes issues when the guys get thrown around!