The Jaigarh Fort and its cannon ...

fernando · 29th July 2019, 05:17 PM

Filipe, what a treatise !!!
Definitely your luggage of these things scares me off discussion.
Still, the only experience i have in this particular, is an article (where i was most kindly appointed co-author) on the Westley-Richards (Monkey tail) pistols, of which i had a couple at the time; a version that ended up being only produced for a Portuguese contract (1000 units). Incidentally their failure to be accepted by the British Board of Ordnance was not a gas leakage issue, described the Board as "absolutely gas tight", but their non military advantage.
Back to early artillery, i dare realize that those Orban/Munir Ali guys were smart enough to circumvent problematic solutions like those applied to Berços, for one ( direct plug into barrel and quarter turn rotation), or any other pivoting systems. A screwing principle; not just a quarter or half turn method but, the whole of four threads rotation. This prevented their minds to predict the advent of the gasket or the washer. And adding to the fact, according to the Brits that, the threads were impeccable, i wander if even Lucifer could escape through them. This still not excluding some lubricating/sealing resource, like organic grease.

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Philip · 29th July 2019, 11:48 PM

Obrigado, Nando, pela reintrodução ao sistema retrocarga "rabo da macaque".

Quite an interesting system since it was apparently self-lubricating.

Back to the screw breeches of the Orban cannon -- you mentioned some organic grease as possibly having utility as a backup sealant if the threads were not fitted tightly enough. I'm thinking, in such eventuality, the natural tendency of black powder to form all that dense residue during combustion would have served the purpose quite well since it would have built up during successive shots without the breech being opened each time.

The observations made by the British, and the Greek expert you mentioned, about the quality of fit of these screw threads (as pertaining to the so-called Dardanelles gun) is still an amazing thing. Considering the era in which it was made and the nature of measuring tools and fabrication processes at the time.

And especially when you compare these achievements with the Portuguese introduction of their methods of gun making to Asia. The armory at Goa improved greatly on the basic processes in use at the time, and brought the concept of threaded breech plugs for musket barrels to the Orient. However, as historical literature and surviving guns show, Asian cultures did not take naturally to the turning of screw threads despite their skill in other aspects of metal craft.

It was a difficult lesson. In Iran, the Persian gunsmiths did not even trust the method (maybe to hide their lack of motivation to master the skill?) and through the 17th cent. preferred to use forged-in-place plugs (often anchored with a cross pin), saying it was stronger. The Japanese were almost allergic to screws, they used similar means to seal their barrels and even avoided all screws in constructing their gun locks, which were made all of brass to better suit the assembly methods they preferred (same for the Malays). A scholar writing a PhD thesis on the introduction of guns to Korea shared a Japanese text with me, describing the earliest attempts to cut threads in iron in that country -- the craftsmen tried to use chisels to shape the spiral, which was doable but far from ideal for male threads but virtually impossible for the female threads.

Indian and Chinese artisans eventually got somewhat comfortable with screw threading thanks to repeated experience with European technicians, but when it came to firearms, the tendency to avoid it was still apparent into the 19th cent. Very few Indian toredors or matchlock muskets use anything other than pins or rivets to secure their parts.

So we have to give those 15th cent. Turks A LOT OF CREDIT.

29th July 2019, 05:17 PM	#1
fernando (deceased) Join Date: Dec 2004 Location: Portugal Posts: 9,694	Filipe, what a treatise !!! Definitely your luggage of these things scares me off discussion. Still, the only experience i have in this particular, is an article (where i was most kindly appointed co-author) on the Westley-Richards (Monkey tail) pistols, of which i had a couple at the time; a version that ended up being only produced for a Portuguese contract (1000 units). Incidentally their failure to be accepted by the British Board of Ordnance was not a gas leakage issue, described the Board as "absolutely gas tight", but their non military advantage. Back to early artillery, i dare realize that those Orban/Munir Ali guys were smart enough to circumvent problematic solutions like those applied to Berços, for one ( direct plug into barrel and quarter turn rotation), or any other pivoting systems. A screwing principle; not just a quarter or half turn method but, the whole of four threads rotation. This prevented their minds to predict the advent of the gasket or the washer. And adding to the fact, according to the Brits that, the threads were impeccable, i wander if even Lucifer could escape through them. This still not excluding some lubricating/sealing resource, like organic grease. . Attached Images

29th July 2019, 11:48 PM	#2
Philip Member Join Date: Dec 2004 Location: California Posts: 1,036	screw breeches and monkey tails Obrigado, Nando, pela reintrodução ao sistema retrocarga "rabo da macaque". Quite an interesting system since it was apparently self-lubricating. Back to the screw breeches of the Orban cannon -- you mentioned some organic grease as possibly having utility as a backup sealant if the threads were not fitted tightly enough. I'm thinking, in such eventuality, the natural tendency of black powder to form all that dense residue during combustion would have served the purpose quite well since it would have built up during successive shots without the breech being opened each time. The observations made by the British, and the Greek expert you mentioned, about the quality of fit of these screw threads (as pertaining to the so-called Dardanelles gun) is still an amazing thing. Considering the era in which it was made and the nature of measuring tools and fabrication processes at the time. And especially when you compare these achievements with the Portuguese introduction of their methods of gun making to Asia. The armory at Goa improved greatly on the basic processes in use at the time, and brought the concept of threaded breech plugs for musket barrels to the Orient. However, as historical literature and surviving guns show, Asian cultures did not take naturally to the turning of screw threads despite their skill in other aspects of metal craft. It was a difficult lesson. In Iran, the Persian gunsmiths did not even trust the method (maybe to hide their lack of motivation to master the skill?) and through the 17th cent. preferred to use forged-in-place plugs (often anchored with a cross pin), saying it was stronger. The Japanese were almost allergic to screws, they used similar means to seal their barrels and even avoided all screws in constructing their gun locks, which were made all of brass to better suit the assembly methods they preferred (same for the Malays). A scholar writing a PhD thesis on the introduction of guns to Korea shared a Japanese text with me, describing the earliest attempts to cut threads in iron in that country -- the craftsmen tried to use chisels to shape the spiral, which was doable but far from ideal for male threads but virtually impossible for the female threads. Indian and Chinese artisans eventually got somewhat comfortable with screw threading thanks to repeated experience with European technicians, but when it came to firearms, the tendency to avoid it was still apparent into the 19th cent. Very few Indian toredors or matchlock muskets use anything other than pins or rivets to secure their parts. So we have to give those 15th cent. Turks A LOT OF CREDIT.