Results 631 to 645 of 696
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9th June 2018, 03:25 PM #631
Bessemer could well be correct that in general Indian Wootz was dreck, in respect to high volume steel production ...
However, the information I've seen suggest that the source of the ore used to make the Wootz favoured by the Damascus smiths contained "just the right" level of impurities of alloying elements such as Tungsten, Vanadium, Chromium and Manganese -- and it was these impurities that contributed to the steel produced by the Damascus smiths. Wootz sourced from other ore bodies didn't have the right mix of impurities, so once the "Damascus" ore body was depleted, there was no longer a supply of "Damascus" Wootz.regards from Alberta, Canada
ian
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9th June 2018 03:25 PM # ADSGoogle Adsense Advertisement
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10th June 2018, 05:10 PM #632
That was kind of my point.
Dave (D.W.) and truckjohn have been enthusing over the performance of chisels from the era before metallurgy had developed into the science it is today. A time, from what I've read, when experience with the material (and a good dose of luck) was all that stood between success and failure. I recall a description from around 1913 / 1914 of a worker in a foundry in England whose primary skill was being able to tell by eye whether a metal billet was hot enough or too hot for the next stage of production -- a worker who was one instrument away from having his skills down graded to irrelevant.regards from Alberta, Canada
ian
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11th June 2018, 11:11 AM #633SENIOR MEMBER
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Remember that they have found forged 100% martensitic steel hardened and tempered tools in the middle east - axes, pick axes, and such - from 1200 bc... That's 3,000 years ago...
That's a pretty good indication that forging and heat treatment have been "mature" technologies for a LONG time now.....
The trouble they had was not what to do with good steel - but rather simply getting good steel.. The trouble with getting good steel is that you actually *need* to know how to do chemistry on the ore to see what you have got and then how to fix it..... So what happened was that they would get some good ore, make some good steel - then work through that layer into some worse stuff and the steel would go bad.... And nobody really knew why... That's the part where modern chemistry and science made a huge difference.
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11th June 2018, 11:22 AM #634SENIOR MEMBER
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So I tested another vintage chisel on plywood. I shaved off about 2x the plywood that wiped out the edge on Aldi and current Marples chisels... Stopped while I was ahead when it started crumbling spruce end grain rather than paring clean... It was still sharp enough to go a LONG time longer on plywood....
I think we need to get a quality vintage chisel or two into Rob's hands for testing... Not a miscellaneous unknown quality/vintage like the Berg tested earlier - but a good one we already verified will go the distance....
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11th June 2018, 12:04 PM #635
Damascus process patent, now expired.US5185044.pdf
Innovations are those useful things that, by dint of chance, manage to survive the stupidity and destructive tendencies inherent in human nature.
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11th June 2018, 05:37 PM #636
that is what I find amusing about the discussion you and Dave have going.
You are comparing steel performance from the era when "nobody knew why" some steels were better than others.
Perhaps the reputation of Swedish steel from before WW2 is based on the quality and consistency of the Swedish ore?regards from Alberta, Canada
ian
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12th June 2018, 01:10 AM #637
Relatively low P and S content. The cleanness of Swedish pig and bar iron was important in the period before techniques for controlling these elements were developed in the latter part of the 19th century. Sheffield locked up the iron market by negotiating exclusive supply contracts with the Swedes that limited the access of other makers to the preferred feed stock. Iron was extremely variable in quality before then. Russia was also a significant source of supply though the quality wasn't as good as Swedish.
Innovations are those useful things that, by dint of chance, manage to survive the stupidity and destructive tendencies inherent in human nature.
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12th June 2018, 01:17 AM #638SENIOR MEMBER
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Ian my friend....
2 things...
Known unknowns - they knew the incoming steel quality could be variable.
And
There is a giant sea of difference between successfully doing things and being able to accurately explain specifically why it does what it does....
So with those 2 things going on....
Dealing with known unknowns.. Rigorous incoming materials test/inspection that included making stuff out of the material and testing the stuff you make... Multiple layers of these functional tests... And those places did a LOT if incoming inspection... Because they knew HOW to distinguish good steel from bad steel from a functional perspective.. So they rejected the bad stuff.... And they knew how to make good tools out of good steel....
And these sort of functional tests to reject bad materials are still built into trades work all over the world...
....
How vs Why... Often as not in trade work - the "WHY" explanation makes no sense what so ever because it's just the fellow's crazy mental model.. It's not how his hands accomplish the work... It's the explanation which comes out of his mouth... He does the work the way he was taught to do the work by his master + whatever improvement he has come up with....
You should hear some of the explanations of the best guitar makers in the entire world on how guitars work... The BEST... And their mental models make literally no sense.... One particularly famous fellow smokes a bunch of weed and listens to "The Tone Faeries" tell him what to do... But his guitars are some of the finest in the world - so should we accept this as true? Or just accept that he is a bit loony but manages to make fantastic instruments?
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12th June 2018, 01:41 AM #639
Carbon was 'measured' by breaking the bar iron stock and examining the fracture surface. Reportedly an experienced eye could judge to within 0.1%. One problem with this type of experience driven approach is that when the observer changes so do the observations. Another problem is that there is no way to convey this information over distance other than having the observer travel.
Innovations are those useful things that, by dint of chance, manage to survive the stupidity and destructive tendencies inherent in human nature.
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12th June 2018, 08:31 AM #640SENIOR MEMBER
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Machines certainly make it far easier to get good results without both years of experience and a highly trained eye...
But often the highly experienced tech with the highly trained eye is still far more accurate than the machine... This is certainly true in industrial color matching...
I would be curious to know if Western Forge or Great Neck tools has an Arc Spark on site for use on all incoming steel or if they simply rely on supplier material certs and standard process settings and tech setup experience....
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12th June 2018, 08:39 AM #641SENIOR MEMBER
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Machines certainly make it far easier to get good results without both years of experience and a highly trained eye...
But often the highly experienced tech with the highly trained eye is still far more accurate than the machine... This is certainly true in industrial color matching...
I would be curious to know if Western Forge or Great Neck tools has an Arc Spark on site for use on all incoming steel or if they simply rely on supplier material certs, standard process settings, and tech experience....
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12th June 2018, 11:06 AM #642
Machines are better.
Innovations are those useful things that, by dint of chance, manage to survive the stupidity and destructive tendencies inherent in human nature.
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13th June 2018, 08:41 AM #643SENIOR MEMBER
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A interesting twist....
I was curious if the trouble I was having with Aldi chisels was (at least in part) due to retained austenite.. The chisels seemed "hard" enough from a bulk standpoint - yet the edges rolled every single time. Sparking them on a grinder seemed to indicate that they should have sufficient Carbon...
So I clunked one in the oven at 480F to temper them and deal with retained Austenite.... Assuming a more or less "regular" High carbon steel - there should be very little retained austenite left...
And it worked! The Aldi chisel cut 2x the plywood end grain after re-tempering....
The last round - it was completely dead... This time - it was starting to crumble/crush spruce end grain but it was still paring plywood. Not only that - but the failure mode changed to light chipping rather than the edge rolling..
And that level of cutting puts it up with "useful chisels"...
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14th June 2018, 12:55 AM #644SENIOR MEMBER
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In my mind at least - this trial is settling into 4 factors greatly effecting edge life:
Sharpening and edge prep
Bevel angle and back prep
Grain orientation, Heat treatment, and tempering (I suppose this is properly microstructure)
Steel alloy (within the range of alloys used for chisels)
You could take it to 3 if you lump bevel angle/back prep into "Sharpening"
And the funny part is that probably - I would expect their effect to run in about that order...
It's pretty easy to see how sharpening and edge prep can end up with edge life effects of over 4:1, perhaps 10:1.... Leave a wire or feather edge on a chisel and it's sharp cutting life goes down a huge amount... Polish up a beat up old edge and the sharp cutting life goes down a lot... And that's really the #1 thing we can control once the chisel is in hand... And so no wonder people argue endlessly about sharpening...
And the effect of appropriate bevel angle and back prep was pretty huge as well... Perhaps even up to 10x or 20x...
The interesting thing is a 2:1 effect (in my hands) of tempering - this indicates microstructure... I believe we see the same thing going on with some Blue Spruce chisels - where some problem with microstructure of the A2 steel causes a huge decrease in edge life.... Simply cutting the chisel blades out of the plate crossgrain could do this... But so could a whole host of other things....
This makes me really wonder what the actual effect of the steel is? The vast majority of steels used shake out in 0.9-1.2% C (except for PM-V11 - which is closer to 1.5%)... And even the stuff we tend to call "Alloy" steel generally isn't very highly alloyed... Once again - the vast bulk of stuff you can buy commercially runs somewhere between Hitachi White/W1/1095 and Hitachi Blue/O1/52100 - so 1/2% to 2% alloy... The exceptions are A2, PM-V11, and the occasional Boutique HSS or D2 chisel...
And so with all that being said - it would be pretty ironic to find out that by and large - assuming quality steel properly manufactured (properly rolled, drawn, or forged) and heat treated for the correct microstructure - the effect of the steel itself was fairly small because it's pretty similar...
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16th August 2018, 05:56 AM #645GOLD MEMBER
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I wouldn't say "nobody knew why" is particularly accurate. I think by the mid to late 1800s, people knew "why", but especially "how" and if you didn't do it right "how" it would turn out.
In terms of those steels, I still haven't found a bad butcher iron. Some are softer than others, but not by a whole lot, but all are very fine.
The difference between then and now is that people are interested in the technical consistency of steel. However, other than a few things like white 1 and 2 (which are absolutely clean, consistent and superb - no two ways about it), nobody is interested in the skill or expense of working with those older plainer steels that move more in heat treatment.
Or to put it at the user level, if you compare a kind of mediocre steel from the mid 1800s, it will still be a better chisel at the same hardness than anything narex makes. Even if it's not razor fine grained, it'll have the basic characteristics of plainer steel, and the user will probably not be able to tell (potentially if poorly chosen for a razor, the final angle of 16 degrees will expose bad steel).
Could we technically do better now? Yes. Do we? No. Well, I guess some of the japanese makers do as well.
You are dead on correct about the reputation of some things:
* swedish steel - it was a gigantic differentiator when english ore was crap. The difference now if there is any is in process, but people still think there's something mysteriously better about it
* solingen knives - decent quality, but I haven't seen anything groundbreaking from them in ages
* solingen razors - same - the new alloy razors that are "plain carbon" steel are a little softer and much less plain than the old razors. Dovo says plainly that it's almost impossible to get and keep a good cutler these days in volumes that will support production
Oh, one other thing comes to mind. The 1095 blades in tidioute knives. It is a thing of absolute joy. They claim 57 hardness or something. In my few examples, they've actually delivered something much harder and fine cutting. Can you cut a pipe with them? No. They're too hard for that. Can you do slicing with them, for a very long time with minimal touch up? Absolutely. I saw a reviewer who judged knives by their ability to cut cardboard, which is a fairly intense slicing test. AS many do, he'd tested all kinds of weirdo modern knives made out of S30V, etc. He purchased a tidioute wall street knife (a simple wharncliffe lockback) and was shocked to find the 1095 knife outperformed all of the other knives he'd tested at slicing cardboard - not better feel (which is a given), but more feet of it.
You know what the consensus of other people was? Must've been a fluke, and $95 is too much for a lockback knife with 1095.
Um. Yeah, OK, but it's no big deal to make a plastic handled crude knife out of sgps, sell it for the same price with an ugly fat blade and find out that it only handles abuse better than the tidioute (which is extremely skillfully made).
Anyway, the idea of "everything is better now, anything else is nostalgia" is not necessarily true. Part of the problem here is that we have new manufacturers who seem to be on the same shooting range but shooting at something other than the targets. They're shooting high right (or low left, whatever you like) and hitting the same spot every time off of the target and boasting about it.
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