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Casting Barrels


DanC
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How exactly did the Japanese cast their barrels? It's not like they could use a clay mold like a bronze cannon or machine it like a modern barrel.

Dan, the Japanese cast some pistols and touch hole cannon, they also used metal worked matchlock barrels. Here is a link which shows how the majority of matchlocks were made.

 

http://media-cache-ak0.pinimg.com/origi ... 98e96d.jpg

 

Bronze matchlock pistol barrel.

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Small bronze cannon.

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Thanks for the link. In both processes illustrated, the are seams that need to be welded - considerably more in the wrapped process. How did they weld the seems strong enough to withstand chamber pressures, without welding the barrel to the mandrel? A proper weld will be just as strong as continuous metal would, but it's not clicking for me how they could make the weld over a mandrel using a forge and hammer process. Basically, how did they heat the barrel enough to make the weld without over heating the mandrel and how did they hammer the seam to weld without warping the mandrel? Since the diameter of the mandrel is relatively small compared to thickness of the barrel wall. :?:

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Dear Dan,

First you take a flat piece of steel and wrap it around a COLD ( clay and ash insulate mandrel ). You then remove the mandrel and heat the seamed tube till it can be forge welded by hammer. You reinsert the cold mandrel and hammer forge the seam. You now take a separate long piece of steel and wrap it about the original tube at about a 30 degree angle until you have wrapped the entire original tube. You then heat the resulting tube and your wrapping until hot enough to hammer weld. The mandrel again is inserted COLD and the gunsmith hammer welds the outer wrapping to the inner tube until you now have one single tube made up of two different pieces. Quite often a third wrapping of a long steel piece is wrapped about the tube at an opposite 30 degree angle the full length of the tube, this all is heated yet again, .... the COLD mandrel is again inserted and the gunsmith hammer welds this third layer to the tube until the tube appears as one solid tube. It is however now laminated ( remember how plywood is laminated from several thin slices to form one sheet ) Laminated wood or steel is stronger than any one solid piece of the same thickness.

... Ron Watson

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Ron

 

Would it not be very difficult trying to remove the mandrel after each layer of barrel metal is wrapped around it? The metal will have cooled and the mandrel warmed making the fit tighter. Also, how would they hammer the barrel metal to weld without warping/deforming the mandrel? Maybe I am over estimating the amount of hammer force needed to weld the hot metal together. :dunno:

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Dan,

The mandrel is removed and the tube heated repeatedly. If necessary the mandrel was removed by hammer and a thinner steel rod acting as a punch.

You are hammering a hollow on an anvil, ... the anvil takes up a great deal of the energy. It is a very slow process of heating the tube and reinserting the mandrel.

... Ron Watson

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Here is a gonne I made,it is a replica of the Morko Gonne made in about 1350

 

By a HUGE stroke of luck one of my Morkos made it to Sweden,then to the Swedish Milatary Museum. Then a meeting was arranged to meet his Great Grandad.

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It is a lost wax casting made from a positive that I made

Gary

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Dan,

Thanks for setting off an interesting thread. Anything that lets the experts in the Board - in this case Ron - share their insights is wonderful. Mandrel welding has always been a mystery to me and this explanation was useful.

But let me ask about those very late brass barreled Japanese pistols. At least some of these seem like European designs. Were that "machined" (or should we say 'carved'?) or were they cast and cleaned? I wish i could come up with an image, but I can't.

Peter

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Dear Peter,

That is a sticky question. I have never examined a brass barreled Japanese gun ( except for the cannon I own and it was definitely cast ) ... normally a pistol, as I know of no long muskets having brass barrels. Now then, ... the later percussion pistols ( European style box locks ) were in all likelihood machined. Of this I am quite certain, ... but rarely, ... we do see brass or bronze barreled matchlocks. Although I have not had one in hand to examine, ... it is possible given their thicker barrels that they were cast, then finished ... but it is also possible that they were forged.

 

Brass or bronze can be forged, cold and hot. All soften when quenched in water and allowed to air cool. Brass and bronze need to be forged at very low heat, less than orange. They are worked mostly cold because they're pretty soft and will move quite a bit when annealed, and can crack while hot forging, by getting it too hot. If working cold the metal must be anneal often. You also have to be sure not to push them too far in one heat, or they will crack anyway. Personally I forge brass or bronze hot, but just an orange colour and I surmise this is the way a Japanese gunsmith worked a brass barrel for a pistol.

 

Notice that the brass barrel pictured below has an iron Bizen ( breach plug ) which would cause one to suspect the barrel to be forged rather than cast.

If it were cast, ... it would be safe to assume ( note I say assume ) the maker would have cast the entire barrel as one piece as was done with cannon.

 

... Ron Watson

post-1782-14196930916753_thumb.png

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Dear Dan,

 

1. A breach plug allowed for its removal from the barrel thus facilitating the cleaning of the barrel by running hot water and a cloth wipe all the way from breach end to muzzle end. Black powder residue is highly corrosive to iron and therefore the gun must be cleaned after firing to prevent rust and pitting.

 

2. A breach plug being screwed into place allowed for the anchoring of the breach end of the gun into the gun stock.

 

... Ron Watson

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Ron has found a beautifully illustrative example there of a bronze, (gunmetal ie 砲金 Hokin, for the purists) pistol barrel with iron breech screw. :clap:

 

Tanegashima pistols were rather rare in the scheme of things, perhaps one pistol to 100 long guns, but Hokin pistols were rare among iron-barrelled pistols. If I have seen and handled fifty matchlock pistols, only three or four of those had gunmetal/bronze barrels.

 

In the meantime I will be asking some contacts in Japan to see if anyone professes to know whether such barrels were generally forged or cast.

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Dear All,

Too many years a gun dealer. Virtually all gun dealers ( at least English speaking dealers ) refer to bronze as brass when speaking of firearms. You will rarely hear the word bronze used for instance when a dealer is describing an English Blunderbuss. It will almost always be described as a Brass Barreled Blunderbuss. As wrong as it may be, the word Brass is often and incorrectly used instead of Bronze in firearm circles. So forgive me, ... old habits are hard to break. As you will see I'm not alone : https://www.google.ca/search?q=brass+ba ... 36&bih=718

... Ron Watson

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Ron,

 

Been busy with work, :bang: haven't had time to log in. In regards to my last post, if the maker is using thin lead strips as a form of "teflon tape" to seal the loose fitting plug threads (to prevent gas blowing back into the face of the shooter), the shooter is not going to be disassemling his musket in the field to remove the breach plug every time he has a misfire - which I would assume was common with any matchlock and the quality of powder used back then. In a different post topic, Ron mentioned how common it is to find historic matchlocks still loaded, which would support my theory that misfires happened often and clearing them was a pain. Yes, it would be easier to clear a misfire or clean the barrel by removing the breach plug, but I am having doubts on how common this was actually practiced.

 

For Rons other point, how does the breach plug secure the barrel to the stock? I was under the impression the plug had to be screwed in and sealed before the barrel was fastened in the stock.

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Dear Dan C.,

Probably more often than not, ... the inside of the barrel was cleaned without removal of the breach plug. This is accomplished by first plugging the vent from the pan to the barrel with a small piece of wood ( so water does not leak out of the barrel at this opening ). Hot water is then poured down the barrel and emptied out repeatedly ( hot water is a great absorbent of black powder residue ). After repeating this several times, ... the plug from the vent is removed and a smaller amount of hot water is poured down the barrel followed by a cleaning rod with cloth attached. This creates a hydraulic effect forcing water out of the barrel thru the vent thus cleaning any residue from the vent. Any excess water is emptied by tipping the barrel. A clean cloth is then by cleaning rod run up and down the inside of the barrel to remove any left over powder residue. This is repeated using a clean cloth each time until no more residue remains. If the gun is to be stored for some time another cloth dampened with a small amount of oil is run up and down the inside of the barrel to protect it from rust.

 

Now to address your second question, ... the rear end of the gunstock is inletted to accept the breach plug ( bizen ) of the barrel and a brass band encircles the stock at this point to give added strength. The barrel being thus inletted anchors this section of the barrel to the stock. See link to photo of this inletting : http://s557.photobucket.com/user/redhug ... 0.jpg.html

 

The reason black powder Muzzle Loading firearms are often found loaded is that ... in order to unload the gun ( supposing no shot was fired ) ... the easiest way to accomplish this was to fire off the gun anyway, ... but this then necessitated the tedious task of cleaning the barrel. Since without the match the gun could not be fired, ... the gun was perfectly safe to leave loaded and on top of that left you with the advantage of simply lighting a match and inserting it in the serpentine and you were ready to shoot without having to first load the firearm with powder wad and ball.

 

... Ron Watson

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Ron,

 

Looked at the photos, one in particular. It shows a square chisled into the wood, I'm assuming this is sized and shaped to tightly match the breach plug, which would keep the plug end from moving side to side and up and down. I also saw what looked like lttle holes drilled in the stock. Are there shallow holes in the barrel that line up with the stock holes, for wood pegs to keep the barrel from moving forward and backword?

 

If the stock is chisled for the breach plug, this would make me more reluctant to remove the breach plug. If you used too much lead when reinstalling, you may not be able to turn the breach plug in as far, which would prevent the barrel from fitting in the stock properly. All of which goes back to may previous point, of why bother going to the effort of trying to make a threaded breach plug in the first place and not just weld the end of the barrel closed after the mandrel process was finished? Did all tanegashima have threaded breach plugs, or just the fancy ones? Did all European muskets use threaded breach plugs, or was this mostly unique to the spanish model originally introduced to Japan, who figured it was necessary to replicate in theirs?

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Ron,

 

Read the bottom of your post. In my limited experience with black powder, leaving a load in the barrel for any period of time just results in a misfire, powder absorbing humidity or something :dunno: . Even with modern muzzel loaders some of the guys use when they come hunting at my place, one guy lost a deer when his gun wouldn't fire in the morning, after leaving it loaded over night from the the previous afternoon hunt. Cleared the misfire, loaded new powder from the same batch, worked fine.

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Dear Dan C.,

Yes, ... the breach plug ( bizen ) fit snugly into the square inlet in the stock. Along the bottom of a Tanegashima barrel are small half moon shaped tits with a hole ( ana ) which lined up with pin holes in the side of the stock thru which passed a bamboo peg ( mekugi ) for securing the barrel to the stock. I totally agree with you that the Japanese of the time rarely removed the breach plug ( bizen ) for cleaning the barrel. Although we can always find exceptions the majority of Tanegashima employed threaded breach plugs ( bizen ).

 

Most European gun makers also employed threaded breach plugs usually so tightened as to be nigh on impossible to remove as the breach plug also had attached a protrusion to attach the barrel to the top of the stock and it was important that this be exactly placed and repeated removal of the breach plug would have eventually caused the breach plug to get out of alignment. Some makers attached the breach plug by sweating into place ... and these breach plugs were impossible to remove. I know of no maker whom welded the breach end of the barrel closed ... Japanese or European.

 

Although it is possible for the powder of a loaded firearm to absorb moisture causing a misfire, ... it is rare. What most likely happened to your friend, is that bringing the gun into a warm environment for the night after having been exposed to a cold environment during the day caused condensation which allowed moisture to enter the vent and dampen the powder at this critical point.

 

I have unloaded 3 separate Tanegashima which had been loaded in some cases perhaps 200 years ago and the powder was as dry as the day it had been originally loaded. I have also unloaded an English percussion rifle and the powder was almost solidified. It all depends upon how and where and in some instances the climate the gun was stored in.

 

... Ron Watson

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If the threads are not there particularly for convenience, then the only other reason for them is structural - a screw is harder to pull out than a nail. If a piece of round bar was just hammer welded(or sweated?) into the breach, would the repeated chamber pressure from firing be enough to crack the seams between the barrel and plug? I'm just not getting the threading. :bang: Why would old blackpowder barrels need threaded breach plugs, when a modern howitzer is fine with a simple wedge breach block. :bang:

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Dear Dan C,

The reason breach plugs were threaded was probably in the case of European manufacture a more convenient safer way of closing off the breach than trying to forge weld the breach plug in place with its inherent possibilities of air spaces and poor joining of barrel to breach plug. Remembering the Europeans had by a fairly early time developed the tap and die ( I have tried to discover the invention date of the this specialized tool, but to no avail ) whereas in Japan such technology arrived rather late. It was probably still in Japan a risky unsure process this welding a cylinder of metal to the inside of a barrel and therefore they also adopted a crude system of using a threaded breach plug.

 

In the case of a modern howitzer which you give as an example of the lack of need for a threaded breach block, ... the answer lies in the fact that the brass cartridge case expands on firing to provide a gas seal and the wedge breach closure does little more than hold the pseudo breach plug ( brass casing ) in place until the moment of firing and the reduction of gas pressure upon the projectile leaving the barrel.

 

... Ron Watson

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Dan C, Ron, When I was in harness, we did a number of x-rays on Indian gun barrels at teh Royal Armouries and they did just hammer a lump of metal into the breech end of their barrels. It was difficult to say whether they were actually welded or just hammered in hot so that the contraction on cooling gripped the plug. Many of their barrels were made by wrapping a strip spirally around a mandrel and welding it together. I used to have a part of one that had been badly welded and had 'unwound' during shooting. I bet that gave the bloke a fright.

An early Portuguese book on gun making describes how the iron mandrel should be allowed to become rusty and to coat it with lime so the barrel does not become welded to it during the forging of the barrel. In Belgium (Liege) and in Birmingham, where the were making hand forged barrels into the 20th century, the strip wound around the barrel was shaped to a trapezoidal section so that when wound on the mandrel each turn overlapped the previous one to get a better weld. They also from time to time banged the end down on the anvil with the thing at welding heat causing the turns to weld together. Those guys used to create the strips from different steels that were twisted together in all manner of ways to give patterns in the finished barrel when etched. There is at least one barrel, illustrated by Greener the Birmingham gunmaker, that has the name 'Liege' worked into the patterning of the strip.

Ian Bottomley

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Dear Peter,

That is a sticky question. I have never examined a brass barreled Japanese gun ( except for the cannon I own and it was definitely cast ).......Although I have not had one in hand to examine, ... it is possible given their thicker barrels that they were cast, then finished ... but it is also possible that they were forged.

Ron, I have assumed that this one at least was cast, what do you think?

 

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