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7th January 2018, 03:06 AM #76
A summary of what the various elements used in steelmaking confer on the product: https://www.leonghuat.com/articles/elements.htm.
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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7th January 2018 03:06 AM # ADSGoogle Adsense Advertisement
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7th January 2018, 06:22 AM #77
Rob, I'm pretty vague when it comes to some of the technology -- being more interested in the end product* than the process -- but after reading your reference to puddling, I suspect that what I was referring to was the replacement of puddling with other iron making processes towards the end of the 19th century.
* back in NSW, there are around 8 wrought iron bridges built in the period 1865 to 1890 that are still in service. Determining whether a crack is fatigue related or just a characteristic of the wrought iron material has become a very specialist skill or even art.regards from Alberta, Canada
ian
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7th January 2018, 07:33 AM #78
A Nation of Steel by Thomas Misa is a very nicely done summary of the industry in the US. The Eads bridge in Saint Louis Missouri is similarly old and has an interesting place in early steel technology https://en.wikipedia.org/wiki/Eads_Bridge.
Nation of Steel cover shot.JPG
This book is part of the Studies in the History of Technology series published by Johns Hopkins University Press. https://jhupbooks.press.jhu.edu/search-books/field_series/416?search_api_views_fulltext=%20&sort_by=field_publication_date
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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7th January 2018, 08:14 AM #79
If we're sharing pictures of old bridges
https://en.wikipedia.org/wiki/Menangle_Railway_Bridge one of the oldest, if not oldest, surviving box girder bridge in the world
another bridge of similar design and age https://en.wikipedia.org/wiki/Victoria_Bridge_(Penrith)
Bathurst-kelso Railway Bridge | NSW Environment & Heritage
regards from Alberta, Canada
ian
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7th January 2018, 11:37 AM #80
You are absolutely right to correct me on that, Ian. Definitely wrought iron for forging. My blacksmith ancestors will all be rolling over in their graves in dismay, all 400yrs of them!
giant Cypress: Japanese woodworking tool punk • Anchor chain erratum/addendum for Shop Talk Live
Sent from my ZTE T84 using TapatalkStay sharp and stay safe!
Neil
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2nd February 2018, 02:14 PM #81
Here are the results for the HR-150A
and for the Ames 4-4.
All of the measurements I'm reporting thus are within about half an HRC unit of the real hardness at the hard end of the range. Not likely that such a difference would matter in a woodworking handtool. Might be important in production tooling though. I'd been putting off such an analysis because it's not very interesting to do but now at least it's done. These results are derived from the raw, i.e. instrumental readouts, not corrected data. I think I'll have my statistician friend check my results too.
BTW, Footprint didn't give me a response.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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3rd February 2018, 01:21 PM #82
I know that this isn't a sharpening exercise, per se, for you Rob, but I did find those results very informative.
Putting aside variations conferred by different edge angles, sharpening jigs and expertise in using them, clearly there are diminishing returns in sharpening above #10,000 in terms of the time required on a stone above that grit (and also the cost of the very high grit stones) given that there are no measurable or predictable benefits of doing so, at least up to five cuts.
This is the first time I have seen any measurable evidence for this.
The durability of an edge beyond five cuts provided (or not) by the stones >#10,000 is a separate issue. My experience with high-end Japanese kitchen knives is that the the higher the grit the longer lasting the edge, but whether the extra time, effort and money on the >#10,000 stones is worth it is probably just a matter of personal preference.
I appreciate that this thread is about woodworking blades, their steels and their cutting characteristics, but I couldn't resist noting Rob's very interesting findings on sharpening on stones above >#10,000. IMO, it is worthy of a separate thread in sharpening.
Apologies, Rob, if I have taken your thread off at a tangent.Stay sharp and stay safe!
Neil
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3rd February 2018, 06:19 PM #83Intermediate Member
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Disregard. I reread the thread
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4th February 2018, 01:55 AM #84I know that this isn't a sharpening exercise, per se, for you Rob, but I did find those results very informative.Apologies, Rob, if I have taken your thread off at a tangent.
Hi Niel,
No problem. As I mentioned above, the limiting slopes analysis I've done is necessary in the determination of the true accuracy and precision of my instruments. Given that my findings and conclusions challenge common wisdom at times this exercise should help to allay the concerns of the more technically minded readers of my posts and further, I think it appropriate for those questions to be asked and answered to the best of my ability.
All of my reported hardness values are corrected for slope and offset, i.e. calibration - all of the instruments require at least some correction. The Ames and New Age instruments are remarkably stable over time. I haven't seen any appreciable drift in their calibrations in the time that I've owned them. The HR-150A formerly required frequent checking because I had it set up on a small cart due to space issues. Last year however I found it a home and built a steel table of 11 ga. 1.5" square tubing - calibration drift is no longer a problem .
This is the first time I have seen any measurable evidence for this.
The reason I embarked on this course is to provide some substantive answers and help to clear the fog of opinion that surrounds sharpening in the woodworking handtool area. I suspect that one of the central reasons that this issue is so contentious is the deficit of data supporting the opinions of those who hold forth on the subject.
Before beginning this study I was content to sharpen my edge tools using any combination of Tormek, synthetic oilstones, diamond plates and one King waterstone that I'd been given applying a 'good enough to get the job done' standard.
While this approach was more or less adequate I was still not satisfied with the results so I looked to Forum members for their insights and failed to find anything resembling consensus. Given all of the squabbling over the subject I resolved to address the issue systematically.
...clearly there are diminishing returns in sharpening above #10,000 in terms of the time required on a stone above that grit...
Don't get me wrong, the higher grit stones offer a measurable reward. It is however hard-won and, depending on the metallurgy of the edge being sharpened, may or may not be worth the effort and expense, especially for a woodworking tool. Might be critical for a sushi knife or some similar application.
On the issue of Japanese blades and blade technology I highly recommend this book.
Japanese sword book cover shot.JPG
It's the most perfectly composed technical history book that I've ever encountered. The balance of exceptional photography and illustration, history and technical content is ideal.
Regards,
RobInnovations 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 February 2018, 01:54 PM #85
More data
Circumstances have been uncooperative for a significant fraction of the time lately so...
The Takahashi and Narex chisels were new and thus may, hypothetically at least, have a layer of decarburized steel at the cutting faces. The Berg and LV PMV-11 were both used and any decarb should have been removed. I suspect that the Blue Spruce butt chisel is showing this effect too.
Interesting that the Narex, Berg, Marples and Sorby chisels are all pretty bad. I don't understand why the Bergs are held in such high regard - the shark decal maybe? The Narex and Berg both had palpable burring of the cutting edge after the first paring increment, i.e. a couple of grams sliced.
The Takahashi holds an edge surprisingly well for a carbon steel blade. The PM-V11 is okay, about as good as the Blue Spruce paring chisel but not as strong as I thought it would be.
No pattern of hardness and edge retention.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 February 2018, 08:04 PM #86
Rob, I did some "real world" tests (but still quantitative) about 5 years ago, comparing Koyamaichi white steel, Veritas PM-V11, Blue Spruce A2, and vintage Stanley 750 (high carbon steel) in tests that involved chopping dovetails.
Part of my conclusions were: "The PM-V11 and the White Steel really do deliver. The gap between them and the A2 and O1/HCS is very large. There is no appreciable extra effort to hone the steels when used with modern waterstones, such as Shaptons (used here) or Sigmas."
Article: http://www.inthewoodshop.com/ToolRev...sCompared.html
The edge quality difference of the Veritas and the Blue Spruce was very large, and very different from your results. Can you comment?
Incidentally, I share your thoughts about Berg, of which I have owned two sets. They are decent chisels, but not outstanding with regard edge holding.
Regards from Perth
DerekVisit www.inthewoodshop.com for tutorials on constructing handtools, handtool reviews, and my trials and tribulations with furniture builds.
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13th February 2018, 12:07 AM #87
Hi Derek,
The Veritas is by no means significantly dulled by my testing, note the Y axis of my graphics above. The Veritas range is about 100 gm., a difference only just noticeable from the standpoint of how the chisel feels. The lower slope of the Veritas graphic is the type of behavior I expected to see similar behavior for all of the chisels, i.e. more or less progressive edge degradation.
The negative slopes are a puzzle and I don't know what is going on there yet. I'm going to have a look at the edge degradation of the better performing chisels with microscopy after I finish with this particular series of experiments.
I plan to add Blue Spruce dovetails, the Japanese chisels I bought from Paul, another Japanese crank neck chisel I have, and a Sorby framing chisel to this dataset. I'm also thinking of including the Funmatsu Nezumi chisels that you tested and something from Stanley.
I've looked at your study. The obvious difference is that you're chopping with a mallet and I'm paring by hand. As such the changes in the edges that I'm measuring for the Veritas would likely be imperceptible in your testing. The Berg and other poor performers would certainly immediately show degraded performance in chopping. If I can feel a burr after paring a couple of grams of pine I'm sure that hammer driven chopping perpendicular to the end grain would do much more damage.
Regards,
RobInnovations 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 February 2018, 03:41 PM #88
perhaps one reason is that in their heighday the "competition" to Berg was even worse.
Another possible explanation is that a previous user removed the temper.
With me in Canada I have a couple of Bergs that belonged to my father -- these chisels were probably purchased sometime before 1960.
Without doing any analytical tests, my impression is that, in terms of usability, dad's Berg's are on par with LN's A2 chisels.
Admitedly, the Berg I reach for most frequently is sharpened to a different bevel angle than the LNs.regards from Alberta, Canada
ian
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13th February 2018, 06:06 PM #89Taking a break
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I found some old Berg chisels in the boss's bench a while ago and thought I'd sharpen them...the grinder just chewed through the steel. I'm sure there must be a reason behind their reputation, stuffed if I can figure it out though
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13th February 2018, 09:29 PM #90
The Berg hardnesses are right in with the rest of this lot at HRC 59.5 and there isn't any evidence that the chisel I used for the cutting is damaged by overheating. The hardness was determined by measuring 5 points on each of three different chisels.
I read a description of the Berg heat treating process and the quench was reportedly into lead. Do that process for long enough in a building closed up against the Swedish winter and you might end up believing anything.
perhaps one reason is that in their heighday the "competition" to Berg was even worse.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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