Shotley Bridge swordmakers

[kronckew]

let's not get our terms mixed up.

annealing is heating the metal to the critical point then cooling it slowly to make it softer and more workable. sometimes the hot steel is covered in an insulate and allowed to cool overnight of for a couple of days...

hardening is done by heating to the critical temp, at which point the steel is no longer magnetic, then cooling it rapidly in oil or water. too quickly can cause excess stress and cracks. modern steels rarely are hardened by full immersion in cool water. hardening produces a steel that can be brittle, so this hardness is then tempered to reduce internal stresses producing a more shock resistant material.

tempering is done by reheating the hardened steel to well below the critical, holding it there for a controlled time to relieve the stresses then allowing it to cool in air. tempering reduced the hardness as well as the fragility. hard edges last longer but can flake off bits or even shatter like glass, a tad too soft is better than a tad too hard. you can bend a bent knife back to shape, but not one that has snapped.

specialty alloys can have variations in the heat treatment cycles including using liquified gases for sub-cooling to produce known properties and crystal formations. morden steels have fairly strict time and temperature regimes for annealing, hardening, and tempering that are digitally controlled with little room for deviation.

heck, asian smiths have been known to produce repeatable differential heat treatments, differential hardening, and tempering in one step by pouring boiling water from a teapot onto the edge of a weapon that has been heated to the correct color as judged by the master smith. this produces a softer less fragile spine graduating to a harder edge supported by the tougher spine. only takes a few decades of training and practice.

it's all a balancing game, you must be hard enough to hold an edge thru a reasonable amount of use before it must be resharpened, but not so hard it snaps or loses chunks of the edge. the blade must be also tough enogh to flex and return to shape without either getting permanent set, or snapping. again, like in japanese swords, a bend can be field corrected by a swordsman, a fracture cannot.

p.s. - don't take 'forged in fire' as an instruction manual in how to
produce or test, or use a good knife or sword.

[urbanspaceman]

Thank-you yet again Ibrahiim, well done indeed. I noted mention of her blog in your earlier post (15) but I didn't read beyond that chapter on Bygate.
She is hosting an event on the 17th in Gateshead: it's for her latest book but I think I will go and talk to her anyway. She appears to be mining the same seams as us in many places. Her intent is fiction based on the SB swordmakers so I'm sure she will welcome an opportunity to swap notes.
I wondered what had happened to Jim - he was conspicuous by his absence - but he return emailed me to say he will be back soon.
I'm going to – hopefully – talk to Jenny Morrison tomorrow (head of archaeology for Newcastle county) if she emerges from the pile-up of work during her vacation.
I've had no response from the Royal Armouries, or the two Vintons I emailed at the weekend; still, patience prospers.

[urbanspaceman]

This is the opening chapter of my intended local-history book, starting by describing a little bit of the mystery and science behind a perfect sword-blade. I introduce this here because I know there will be many folk reading this thread who know a great deal more about the subject than I do, and will hopefully correct any/the mistakes I may have made.
Wootz!
It started in India around the 6th century BCE and it was fundamentally the 'crucible steel' developed by Huntsman at Sheffield in 1742; although, even to this day, and despite our scientific techniques, there remains much that is not understood or replicable about Wootz steel, which is both superplastic and very hard: precisely what you require for sword-blades. However, when you consider that India's iron-age began almost a thousand years earlier than ours, then their superiority all begins to look a little unsurprising.
To make Wootz, they sealed cubes of malleable (or pasty) iron-ore into melon shaped clay containers, along with specific chopped-up dried wood and leaves – not charcoal though which is no substitute, as it does not contain the carbon nanotubes which are vital – then put them in an oven and blasted them with high temperatures for four hours; removed the result and cooked it in a charcoal fire for several hours until the excess carbon was extracted. Hey Presto: Wootz!
It wasn't until the 1600s that high carbon alloys even became apparent over here in Western Europe; although once the Crusaders got under-way, they became painfully aware of the incredible characteristics of swords used in Persia made from Indian Wootz, and referred to as Damascus blades.
This Damascening of blades made of Wootz steel was not an entirely mechanical process – based on folding and/or twisting the steel during forging (known as 'billet' welding), and occasionally acid etching – it was also crucially dependant on the unique molecular properties of the Wootz.
Very simply put (if that's possible) it is now understood to be a eutectoid steel: analyses tell of the presence of carbon nanotubes enclosing nanowires of cementite, with the trace elements/impurities of vanadium, molybdenum, chromium, etc. contributing to their creation during cycles of heating/cooling/forging. This resulted in a hard, high carbon steel that remained malleable.
Of course, there does require the forging process, with its complex rules regarding the quenching of the hot steel in order to temper it, and therein exists a whole alternative science-fiction with 3,000 years of secrecy and fairy-tales surrounding it; and among those myths, some may well have contained an element (pun intended) of truth, for example:
According to Dr. Helmut Nickel, curator of the Arms and Armour Division of the Metropolitan Museum of Art in New York, legend had it that the best blades were quenched in ''dragon blood.'' However, a little closer to reality – but only just: in a recent letter to the museum, a Pakistani gentleman told of a sword held in his family for many generations, quenched by its Afghan makers in donkey urine. This concurs with some medieval blade-smiths over here, who recommended the urine of redheaded boys or, more realistically, from a ''three-year-old goat fed only ferns for three days.'' Were someone to analyze these bodily fluids, they may well discover the presence of elements pertinent to metallurgy; then again, modern scientists may not have the time or inclination to start breeding goats... or red headed boys.

[urbanspaceman]

ps BTW
I found the contact number and called John G. Bygate today. I wanted to know if he had continued research once his book was published - he didn't - and also if he objected to his work being made publically accessible via this forum, and he was, as I had anticipated, very pleased to know his brief endeavour has now been disseminated amongst interested parties. I also gave him the link to this forum thread so he could monitor proceedings; and maybe offer input should the need arise.

[urbanspaceman]

I just wish I could have done the same with Mr. Bezdek; I have so many questions I might have put to him.

[Mel H]

Hello all, I've been a follower of the site for quite a long time and have recently taken the step of 'signing up', this is my first post.
I've long had an interest in the blades made at Shotley Bridge and am enjoying this particular thread, just a quick note to Urbanspaceman. Do you know of the paper written by Rhys Jenkins and read at the North of England institute of Mining and Mechanical Engineers in 1935?
I've not yet had time to digest the full thread so may have missed any mention of it.
M.H.

[fernando]

Welcome to the forum Mel .
You will surely enjoy being here.

[urbanspaceman]

Originally Posted by Mel H

Hello all, I've been a follower of the site for quite a long time and have recently taken the step of 'signing up', this is my first post.
I've long had an interest in the blades made at Shotley Bridge and am enjoying this particular thread, just a quick note to Urbanspaceman. Do you know of the paper written by Rhys Jenkins and read at the North of England institute of Mining and Mechanical Engineers in 1935?
I've not yet had time to digest the full thread so may have missed any mention of it.
M.H.

Hello Mel. I am pleased to have you on board this thread: welcome.
You have reminded me: I am supposed to go down to the Mining Institute and read a bunch of stuff that has come up on this thread; for some reason, I don't seen to be able to open some archives. I know the folks down there and they are not only obliging but enthusiastic about digging out ancient tomes for me. Everything connected to Newcomen is directly accessible there, and that is what I am going to peruse. It's really a remarkable place, and the folk who work there are volunteers for the most part; when you go through the doors, it is like stepping back 100 years or more. Next door is the Lit and Phil as it is known locally: The Literary and Philosophic Society to be correct. Between the two, I would venture that every sparkling mind in the entire industrial revolution has graced its halls; and the Mining Inst's lecture hall is a genuine marvel with an atmosphere that is absolutely beyond compare... and that includes the Royal Institute.
Sorry, I've strayed far from the thread; I just get all gooey when mention is made of those two places. Again, welcome. Please post anything anytime, as Jim said, it is all valuable. I believe that we are beginning to see a light at the end of the tunnel of mystery penetrating Shotley Bridge.