StandingWellBack

You can contact me at rogercdavies(atsquiggle)me.com

This blog has evolved into a review of historical and modern explosive devices, and responses to them. Links are drawn between historical activity and similar activity in the world today. Mostly I focus on what are now called IEDs but I have a loose personal definition of that and wilingly stray into discussions of more traditional munitions, the science and technology behind them, tactical employment and EOD responses. Sometimes it's just about interesting people in one form or another. Comment is welcome and encouraged but I do monitor it and reserve the right to delete inappropriate stuff. Guest posts are always welcome. Avoid any stuff that makes the enemy's job easier for them.

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Entries in 1400-1500 (2)

Thursday
Sep112014

How gun locks were used in IEDs for over 250 years

When I started my research into historical IEDs a few years ago, I came across references to “gun locks” used as initiation mechanisms. The “gun locks” are from firearms such as wheel-locks or flintlocks repurposed to initiate a larger explosive charge.

However I have continued to encounter these mechanisms at every turn of my research. The deeper I dive into historical documents the more I think they were much more common than I had realised. In fact I think they were a usual way of initiating IEDs for about 250 and even for as long as 330 years. I think that’s surprising and worthy of explanation   The wheel-lock and its successors, the snap lock, the snap-haunce and the flintlock are essentially spring loaded levers operating around an axis which contrives to place a spark ignition system in direct proximity to gunpowder. In a firearm the “trigger” is pulled by the person aiming the firearm - the pull of the trigger releases the spring-loaded mechanism. In general terms in an IED the trigger is pulled or released by another mechanism such as a lever or a cord. But it is the same mechanism.

The developments of gun locks for firearms were paralleled and linked inextricably with the development of household locks for doors and chests, and the same people made both.  There is also a distinct parallel in technological development terms with clock making which saw some significant developments in about 1580 with the development of spring driven rather than pendulum driven mechanisms, and one sees this being a mechanism that enables mechanical timing mechanisms in IEDs for the first time at around this date.  But the clock is only a component to release a spring loaded lever, allowing the flint, for example, to strike and cause sparks.   One can still see the influence of clock making in fairly modern fuzes, and I think that’s an area for future research, to explore the early parallels of lock mechanics with fuze mechanics. Indeed the language of clocks and explosive fuzes is very similar in describing components - ”fuzes" and “trains".

I’ve discussed before some of this , in relation to the invention of detonating systems,  but here I want to concentrate on the locks and the derived implications to IED design. 

Here’s an outline of the technology:

Prior to 1500 firearms were fired with "match locks". Pulling a trigger caused a slow burning cord, (a "match")  held on an "s" shaped lever to be pushed into contact with the gunpowder charge. In about 1500 the wheel lock was developed as a sophisticated mechanism to initiate a firearm without a pre-lit match.  The wheel lock is a spring loaded steel wheel which acts with friction against a piece fo pyrite to produce sparks, pushed against it by a spring loaded lever or "dog".   The resultant sparks land upon the beginning of the gunpowder train. (think of a Bic cigarette lighter, yet the thumb which turns the steel is replaced by a spring).  A simple "detent” safety catch is easy to include which prevents the spring loaded mechanism being moved until the device is set up in place.  Thus the wheel lock is:

  1. Safer than using a matchlock where a slow burning fuse ("match”) is introduced to the gunpowder train (not a good idea with a large charge of gunpowder immediately adjacent)
  2. Able to be left in place for as long as the gunpowder doesn't deteriorate
  3. Able to facilitate its containment and concealment (partly due to its small size) within an enclosure, which again a matchlock is not suited to.
  4. Able to prevent the give-away smell of  a burning match and the sight of a glow.

So in IED terms the wheel lock and its sucessors enable ease of use, concelament and safety, all key asopects for someone wanting to use an IED.

Pyrite is used in wheel-locks rather than flint because flint is too hard and the wheel would wear away rapidly. The wheel-lock is quite a complex piece of engineering and therefore expensive, which would have been a discouragement for the “one time use” within an explosive device.  

The snap lock was introduced in the late 1540s. The key to its design is that it is simpler, with less moving parts - simply a spring loaded lever holding a flint that falls on a steel or “frizzen". There is no wheel to wear out, and much less complexity, meaning that it is cheaper and therefore more likely to be “thrown away” in an IED.

The snaphaunce LINK developed in the 1550s and the flintlock LINK developed in 1620, were basically improvements on the snaplock design , allowing the pan to be covered for safety and to keep out the weather - the essential difference between these latter two is the mechanism by which the pan of gunpowder was uncovered.

So, between 1500 there is a period of 120 years of technological development to get from the original matchlock to the safe, flexible, cheap, easy to operate flintlock. Here's a video showing in a bit more detail how a flintlock on a firearm works.

From about the 1540s it may have become an economic option to use a gun lock in a “one time use” IED - perhaps from a broken firearm.

The next issue to address is how the trigger is pulled or released to allow the gun lock to fire.  There are essentially three principle modes of initiation for IEDs, all based around the fundamental idea that the perpertrator does not want to be near when the device explodes -  and the firing lock can enable each one of these three:

  • By command from a distance.  Simply by tying a cord to the trigger of a gun lock a device can be initiated from a safe distance.
  • By a victim’s action.  By tying a cord to the trigger and attaching the end of the cord to an attractive object or some other thing likely to be moved, the perpetrator can cause the initiation by a victim.
  • By timer. if the firing lock trigger is attached in some appropriate way to a clockwork mechanism, then after a set time, the trigger will be pulled.   

The following examples detail use of these three technique from the period between 1585 to 1918 - a significant period of history

In the 1570s the somewhat exotic inventor Ralph Rabbards describes contrivances that require some sort of spring loaded mechanisms to initiate explosives, and at the same time Samuel Zimmerman of Augsberg described explosive devices set off with hidden springs and string.    Zimmermann discusses “booby trapping” a chair that will initiate a device when sat on, and booby trapping a “purse of gold” left lying in the street.    I’m pretty certain that these devices would have used a gun lock initiator - how else would they have been initiated?  The technology was there and there are no other apparent mechanisms available to the bomb designer of the time. 

In 1581, the Polish besiegers of the City of Pskov sent a jewelled casket to the occupants of the city of Pskov. The device exploded when it was opened by the Russian defenders.   This booby trap mechanisms must have been initiated by a gun lock , adapted and contained in the casket.

This link here, tentatively dated to the 1580s shows 4 command initiated devices, initiated by operators pulling a cord from a distance. One has to assume that the cord was attached to the trigger of a firing lock buried in the barrels on the route of the target convoys. Not much changes does it?

In 1585, Giambelli’s clockwork Hellburner was triggered by a clock provided by Antwerp clock maker Jean Bovy.  Now techncialy, that could have been a lever, activated by the clock, which moved a burning match.  But I think a gun lock is more likely.

In 1628 Cornelius Drebbell (the inventor of an early submarine) developed floating devices used (unsuccessfully) by the English Navy against the French in La Rochelle. I have found this description of Drebbels explosive devices, written by Carles Bernard in 1628 in the Mercure Francois:

`During the night between Sunday (Oct. 1st.) and Monday, the English shot ten or twelve floating petards for the purpose of setting fire to the royal French fleet. The body of these petards is of white iron filled with gun-powder and floats on a piece willow wood, through which a spring is made, which when it encountered the bows of one of the royal ships, took effect, which consisted simply in this, that it threw water into the ship with much power; all the others were captured as they floated on the water and did no harm.’

So, my assessment is this - the iron cased charge is mounted on the floating wood platform, some form of spring powered lever acts on the device when it comes into contact with the enemy ships.  I think the most likely technology of the time which could have utilised that spring action is to release the trigger of a gun lock. I’m happy to consider other solutions but to me I’m now fairly certain.  One historian has suggested that Drebbell, who was known to have dabbled in alchemy, may have used the first ever high explosive, the primary explosive Gold Fulminate (discovered in 1602) – but I remain unconvinced. Occams Razor suggests to me a gun lock.

This diagram below from about 1630, shows a clear representation of a booby trap with a basket of attractive objects , within which is a firing lock tied to one of the top objects - lift the attractive object, pull the cord and the firing lock will cause the device to explode. Look carefully and you'll see the lock at the bottom.

In 1645 we have this description of two IEDs, each clearly using a firearm lock attached to clocks.

In 1650 we have this device, using a pistol firearm lock, initiated by the pull of a string. 

In 1764 we have a postal device that utilised a booby trap using a firearm lock. 

In 1776 and 1777 The American revolutionaries used systems that instinct suggests to me were similar to Drebbel’s devices of 1628, but develped by David Bushnell. Buchnell also followed Drebbels lead in submarine vessel ideas.

Here's part of the timing mechanism that Bushnells famous "Turtle" submarine was meant to fasten to the bottom of HMS Eagle. The timing mechanism's gears ultimately tripped a flintlock mechanism to fire a gunpwder charge. (Photo John Wideman)

Bushnell also used floating explosive charges with levers on the outside designed to be pulled when they came into contact with ships, very much like Drebbels devices of 1628. 

This image is a replica of a Bushnell IED that was floated down a river towards the Britsh ships. The lever on the outside causes a flintlock on the inside lid of the barel to be activated when the external lever comes into contact with the side of a ship, or a cable is pulled in some manner.

This image below is of an original revolutionary IED, the inside of the lid of the barrel, showing the flint lock mechanism held in place, to be activated by the lever on the outside. The flinlock shown appears to be from a British made "Brown Bess".

 (My thanks to John Wideman for allowing me to reproduce these images from his book “Civil War Torpedoes” where these pictures provide context for his very detailed and excellent work of later devices.)  

In 1805 Robert Fulton, an American working for the British Navy, (after being rejected by the French) designed a range of explosive devices using gun lock initiators. This diagram, produced by French technical investigators who captured and defused at least one of the devices following an attack on St Malo, shows clearly the firing lock mechanism adapted by Fulton as the explosive initiator. This diagram is one of my best finds.  This is a very sophisticated device and a very sophisticated techncial exploitation of the device by the French. The red annotations are mine, part of a lecture I give on historical technical exploitation.

In 1812, during the war with the British, Robert Fulton (who switched sides again, back to his mother country) used gun locks in a number of attacks using explosive devices on the British.  This attack on HMS Ramillies which was blockading American ports, used a very simple device, and nbot one of Fulton's designs, but nonetheless used firing lock.  It is described by Benjamin Lossing (thanks again to John Wideman for finding this)

In the hold of the schooner Eagle, John Scudder, junior, the originator of the plot placed ten kegs of gunpowder , with a quantity of sulphur mixed with it, in a strong cask, and surrounded it with huge stones and other missiles, which in the event of an explosion might inflict great injury.  At the head of the casks, on the inside, were fixed two gun locks with cords fastened to their triggers at one end and two barrels of flour at the other end, s that when the flour should be removed the locks would be sprung, the powder ignited and the terrible mine exploded. Thus prepared, with a cargo of flour and naval stores over the concealed mine, the Eagle sailed … . she was captured as expected and desired by armed men sent out on boats from the Ramillies.  The crew of the Eagle escaped to the shore at Millstone Point, and anxiously awaited the result. The wind had fallen and for two hours unavailing efforts were made to get the Eagle alongside the Ramillies for the purposes of transferring the cargo to that vessel. Finally boats were sent out as lighters, the hatches of the Eagle were opened and when the first barrel of flour was removed the explosion took place.  A column of fire shot up into the air a full nine hundred feet  and a shower of pitch and tar fell upon the deck of the Ramillies . The schooner, and the first Lieutenant and ten men from the flag-ship on board of her , were blown into atoms and most of those in the boats outside were seriously and some fatally wounded.

Although not involving flintlocks I have details of Fenian IEDs using high explosive initiated by pistols connected to timers in the 1870s, and Lawrence of Arabia’s railway IEDs in WW1 were initiated by adapted martini rifles firing mechanisms - which themselves were an idea copied from the Boers in South Africa in the Boer war.  However all these latter devices were in one sense different – they each actually fired a bullet into high explosive rather than igniting low explosive gunpowder.

I am by no means saying that every IED between 1540 and WW1 used gun locks - but gun locks enabled a simple and reliable way of initiating explosive charges and were used frequently and quite widely during the period.  A gunlock could be used easily to initiate a device, by those three key ways - by command, by the victim or by timer. A gunlock enables concelament and surprise.  I think these facts are crucial to an understanding of how IEDs were used in history.

Sunday
Nov182012

Inventing detonators

I’m intrigued by the chain of historical inventions that led to the modern detonator.

Detonators for explosive charges evolved from firearm trigger mechanisms and I see these as an invention continuum, with one leading to another. Alongside these mechanical inventions, chemical discovery runs as a parallel track, particularly the discovery or primary explosives and high explosives, which detonate by shock (gunpowder being a low explosive which explodes by deflagration)

Initially, I guess the first “initiators” were simply burning fuzes which transmitted a flame to gunpowder. However there is some early mention of a some victim operated mechanisms perhaps using friction devices or steel and flint levers.   See Chinese IEDs here.  

To help undertsand the chain of scientific, chemical, physical and mechanical inventions that took us down this path the folloing rough time line might be useful:

Pre 1400 – Burning fuzes of various types, igniting gunpowder by burning.

Early to mid Mid 1400s - Invention of the matchlock mechanism to initiate firearms. Note that this was definitely a European invention – the Portuguese took matchlocks and introduced them to China and Japan.  (The story of how the Japanese obtained and reverse engineered the matchlock will be the subject of a future post) .

About 1500 – Invention of the wheel-lock, possibly by Leonardo Da Vinci, which introduces a new mechanical action to apply a burning fuze to a specific point.

1540 – The snaplock was invented, using a flint initiator. This was a precursor to the more sophisticated flintlock

1558 – The snaphaunce was developed which incorporated a mechanism for keeping the gunpowder covered until the flint fell, when the cover is opened automatically.  The cover is called the frizzen.

1588, a time initiated system used by Giambelli to explode the “Hoop”, with a timing mechanism causing ((I’m guessing with a snaplock or snaphance) to initiate the charge.

1602  Gold fulminate (the first primary/high explosive) discovered by John Tholde of Hesse.

1610 – The first flintlock initiation system developed The flintlock mechanism is an evolution of the snaphaunce whereby the frizzen is not only a cover for the pan of gunpowder, but also the steel face on which the flint strikes to cause sparks.

1659 Robert Hooke and Thomas Willis discover the primary explosive characteristic of Gold hydrazide

1745  Dr Watson of the Royal Society showed that an electrical spark from a Leyden jar could initiate a small blackpowder charge.

1750  Benjamin Franklin initiates gunpowder with an electrical spark and makes small paper tubes of  powder with two wires inserted and a spark gap created.

1788  Silver fulminate was first made by French chemist Berthollet.

1776 – American revolutionaries used adapted firearm mechanism to make contact mines consisting of “kegs” of gunpowder which were floated down rivers.  The kegs have fastened to the lid a wooden arm which when it touched a target ship connected to an iron pin, engaging a flintlock device from an adapted firearm, causing the main charge to explode.  Note the similarities in principle to much later IED initiators here.  I'll post some images of these "kegs' in future posts.

1777 – Italian scientist Alesandro Volta, describes how he had fired pistols, muskets and a ”mine subacquee” (underwater mine) electrically – it appears he used a hot wire to initiate a glass bulb full of a flammable gas.

1782 – Another Italian scientist, Cavallo, described detonation of a charge of gunpowder, electrically, using an incandescent wire embedded in the powder

1795 - Cavallo uses another method, using gunpowder mixed with steel filings, with two electrical probes embedded in it.

1799 - Fulminate of mercury, a primary explosive later used in detonators was first prepared by Charles Howard. Interesting reports on his experiments are here and I think its very significant indeed that Howard actually tested electrical initiation of mercury fulminate. I note also that Howard refers to French scientists electrically initiating some form of potassium chloride based explosive in the late 1700s.  Howard's description of the experiments he conducted with mercury fulminate are fascinating – clearly he hoped he had invented an alternative to gunpowder, but initiating mercury fulminate within a gun caused some catastrophic damage to his equipment!  There is a great description of how Howard measured the volume of gas produced from a specific quantity of the explosive.

1812 - The Russian military scientist Pavel Schilling developed an electrically initiated IED, as a mine.  My apologies, in earlier posts I credited this to others later in the 19th Century, and I have only recently discovered Schilling’s  (and Volta’s, and Howard's) technologies.  Schilling gradually improved the associated technologies, insulating wire with tarred hemp and copper tubing, and devising a carbon arc initiator.

Also in 1812 - Prussian scientist Sommerring improved the insulation of electrical wire, using rubber and varnish, allowing further capabilities to be developed in initiating explosives.

1820 – American scientist Robert Hare, worked on electrical initiation of flammable gases. Hare also developed a “plunger” type galvanic machine for producing electrical charges for this purpose.  

1822 – Hare used  a hotwire embedded in a pyrotechnic mixture to initiate a blackpowder charge.  In the 1830s Hare also produced a tin tube container packed with powder and with an ignition wire for rock blasting but foresaw the military importance of command initiated explosive charges. 

1829 – A young Samuel Colt initiated an under water charge electrically perhaps using a tarred copper wire.

1831 - The Bickford burning fuze was invented, taking away the guess work about time delays for burning fuses.

1837  Colonel (later General) Pasley of the Royal Engineers developed chemical then an electrical initiation mechanism to explode gunpowder charges under water. Pasley’s work appears to have been prompted by reading a  newspaper report of an “ordnance accident”, in Russia, when Tsar Nicholas I narrowly escaped death when viewing a demonstration of electrically initiated gunpowder charges used to blow up a bridge, presumably developed by Schilling. Pasley read the article and then sought the advice of English scientist Charles Wheatstone to consider how he might use the same concept.  Pasley’s contributions to military engineering are huge, and his explosive related inventions are very significant if only a part of that broader work.  I have yet to find details of Pasley’s chemical fuzes, but his electrical initiation mechanisms used electrically heated platinum wire, with the electricity provided by early galvanic cells. Pasley solved the problem of insulating the wires so they could be used under water, by coating wire with gutta percha. The platinum wire (or foil) provided enough heat to initiate the gunpowder it was embedded in.  However some reports state that the electrical system caused a detonation by a “galvanic spark” so the actual mechanism is still a little unclear.   I’m very intrigued by the chemical fuzes and how they worked, given the nature of the underwater tasks that Pasley developed the explosives for. I think it likely that there would have been some form of command pull to initiate the chemical reaction once the divers were clear and safe.  Chemically the reaction may have been similar to Nobel’s (later? ) designs.

1830s  -  Immanuel Nobel developed chemical initiation mechanisms to initiate gunpowder. The mechanisms used a glass vial containing suplhuric acid, which when broken (usually by an enemy) caused the acid to fall by gravity onto potassium chlorate, which ignited and caused surrounding gunpowder to initiate. These were confusingly called “Jacobi” fuzes after the Russian scientist for whom Nobel worked.  Jacobi led the Russian “armed services committee for underwater experiments” between 1839 and 1856. It is clear that Jacobi’s secrecy prevented international publication of the scientific achievements he made in electrical initiation. Jacobi’s work  from 1839 seems to have been prompted by both Schilling and Pasley.  What is significant is a reference I have found to Jacobi developing “mercury connecting devices” which probably mean some form of mercury electrical switch to initiate contact mines in the 1850s.

1830s, Mercury fulminate was used in copper caps used as firearm initiators taking the place of flint, and making the process of initiating a firearm much less dependent on flint and the weather.

1839 – Other British Royal Engineer salvage operations in Bermuda and in Bengal on the Hoogly river used electrically initiated charges.  I have a great piece of reseacrh to blog about with regard to the Hoogly river operation.

1840s – Samuel Colt conducted extensive work on highly complex electrical initiation systems for sea and river mines.

1848 - Werner von Siemens developed electrically initiated sea mines.

1863 - Alfred Nobel (Immanuel Nobel’s son) published his patent for a practical detonator to initiate nitro-glycerine.  Note that this was four years before his patent for dynamite.  In modern parlance this was a non electric blasting cap, itself initiated with burning fuse.   The detonator consisted of a small blackpowder charge, a wooden plug and a small quantity of nitroglycerine held within a metal cylinder. The black powder is initiated by a burning fuze, which pushes the wooden plug down the cylinder, which then strikes the niroglycerine with kinetic energy.

1865 -  Nobel refined his detonator design significantly, with a small metal tube containing mercury fulminate

1868. H. Julius Smith produces a detonator that uses a spark gap and mercury fulminate.

1875 The electrical detonator using a hot filament was developed independently by Gardiner and Smith