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Post by ShooterMike on Mar 24, 2007 3:37:10 GMT
I was on the phone for about an hour with Angus Trim today, talking about this site, among many other things. He told me several things that I found interesting enough to share.
He asked me if I wasn't the guy on the SBG Forum who had cut the tip off one of his early swords. Hmmm...famous or infamous...where was this going?
He good naturedly noted that I pointed out that I couldn't cut his sword with the same hacksaw I used on a Gen 2 sword. That started a conversation about hardness on sword blades. I asked how hard his blades are and how RC hardness is tested on swords. What he told me was very enlightening.
ATrim sword blades are hardened and tempered in an FAA-certified metal hardening specialty business. As such, they HAVE to test and certify every single piece of steel that goes out the door to maintain their certification. Therefore, every single ATrim blade is really tested at RC 52.
What Gus described to me was how variable the hardness in steel almost always is. Also, he described how a hacksaw cannot reliably cut an RC 52 blade. Gus described how a lot of folks have steel that they think is harder than it actually is.
Anything that approaches RC 50 is pretty darn hard. And most swords are in the RC 46-48 range. So when you see claims of sword blades that are "Oh about 54 to 56 Rockwell", take it with a big grain of salt.
Just thought everyone might find this interesting.
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Post by Deleted on Mar 24, 2007 3:56:42 GMT
That is interesting, I wonder then if the swords that claim to be HRC 52 are really just approximately HRC 52.
-John
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Post by Deleted on Mar 24, 2007 9:20:09 GMT
How it is tested though? I don't suppose they try to cut each and every sword they produce by a hacksaw......... otherwise each of their swords would come with a pretty big hit mark LOL.
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Post by ShooterMike on Mar 24, 2007 13:47:43 GMT
That is interesting, I wonder then if the swords that claim to be HRC 52 are really just approximately HRC 52. -John Or maybe they are 46 or 48 or 50-ish or who knows? Also, I have seen it expressed as "RC" and "HRC". I know it is called the Rockwell C Scale. Anybody know what the numbers mean or how to explain the system? How it is tested though? I don't suppose they try to cut each and every sword they produce by a hacksaw......... otherwise each of their swords would come with a pretty big hit mark LOL. To keep Federal Aviation Administration certification for aircraft parts manufacture, they have to use a large and elaborate set of precise measuring tools. REALLY expensive stuff! But I must apologize, as I didn't really communicate the intent of the conversation. Gus's main business is making parts for the aerospace industry, so those parts go to this heat-treat business and must be tested. He just uses them for his swords because he already has a business relationship established. I doubt that he would go to that trouble otherwise. The point of our conversation (which I botched badly above) was that quoting Rockwell hardness numbers on sword blades is really not valuable. The Rockwell scale is kind of complicated. And just because one blade is harder than another, that doesn't make it a better sword. Generation 2 swords are a good example. They are made in the Philippines. This kind of testing equipment isn't available there. At least not at an available price. I really haven't paid attention so I don't know if Clyde has ever made claims as to Rockwell hardness numbers for his swords. I know from experience (lots ) that Gen 2, Arms & Armor, and Albion blades aren't as hard as ATrim blades. Gen 2 blades and the blade on my Arms & Armor Henry V all have about the same hardness, based on how they are to sharpen with files and stones. Albion blades seem to be about halfway between those and ATrim blades. And I would guess that the Paul Chen blades are about halfway between Gen2/A&A and Albion. All that to say, I would guess that Gen2 and A&A have probably the most historically accurate hardness for swords made in the 1000s to 1200s, probably? But they are all good swords. So the point of the conversation I had with Gus was "Don't put any stock in quoted Rockwell hardness numbers. Most blades aren't tested, due to the expense involved." So if your sword performs well as a sword, just be happy with it. And if you are considering buying a new sword, ignore any Rockwell hardness claims as marketing hype.
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Post by Deleted on Mar 24, 2007 18:17:07 GMT
To answer your question about RC to HRC, the only difference is one is a letter shorter than the other. RC means 'Rockwell C', denoting the method and particular scale used. HRC means 'harness: Rockwell(C)'. So HRC52 is like saying(in a list of statistics: Hardness: Rockwell(C scale): 52
From an industry standpoint, deviation up to +/- 2 points is acceptable. So from an industry standpoint, if you want something RC 52, and they test it to 52, it could ACTUALLY be anywhere from 50 to 54. With Gus's tools and such, I'm sure he's much more spot on though.
Other interesting numbers include: Cold Steel knives are claimed to be RC 56-58 depending on the knife.
Angelswords are claimed to be 57.
Darksword armory claims RC 53.
Paul Chen Katanas that are differentially hardned are claimed to be RC 60 edge, RC 40 spine.
Most albions are RC 48-49.
Most industry companies claim that the ideal hardness for swords is somewhere in the RC50-54 range(right where atrims are). Del Tin Claims RC 50 I believe.
As for most swords on the market, I'm guessing most wallhangers to be RC 40-44ish, which is silly cuz they're STILL brittle(cursed stainless steel). Most 'functional' swords for <$300 I'm guessing to be around 46-47. Maybe Gen2s are 48. I hope so.
And lastly, if I ever get a custom sword, I want to make dang sure that it's at least a solid and documentable RC 50. Preferrably 52 like Atrims are.
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Post by Deleted on Mar 24, 2007 21:28:57 GMT
He asked me if I wasn't the guy on the SBG Forum who had cut the tip off one of his early swords. I see your reputation precedes you. ;D According to the article on myArmoury regarding blade hardness, several of the original specimens tested averaged in the 30-ish RC range, while one or two didn't even register on the Rockwell scale. Other examples measured up to 58 RC. The main point of interest to me was the fact that all the blades exhibited varying degrees of hardness throughout. THis makes sense, as thinner areas or areas around the edges would cool faster and remain harder, while thicker areas or those near the center of the blade would cool more slowly and end up softer. When comparing traditionally made Japanese style blades to western blades, we often talk about the Japanese styles as being differentially hardened, while the western blades are referred to as through hardened. This gives the impression that only Japanese style blades show different degrees of hardness in different areas of the blade. THe truth is that any blade will vary in hardness, depending on what part of the blade is tested. Obviously, the reason we focus on differential hardening with Japanese style blades is because they specifically tried to control the degree of hardness at the edge and at the body of the blade. Western swords were generally (except maybe the Vikings?) hardened without any attempt to differentiate between edge and body, so the differences in hardness were simply a natural result of the hardening and tempering process. Wow! I actually sound like I know what I'm talking about! ;D D'oh! I was going to mention that I recently had a discussion with a knife maker at knifeforums.com regarding a "plains" style dagger he makes, which is a long, wide, double edged blade with a lenticular cross section, and he told me that these blades generally turn out mid-40's RC at the center and mid-50's at the edges, just through the natural process of making them, rather than though any specific intent on his part.
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Post by rammstein on Mar 25, 2007 23:15:25 GMT
thats all fine and dandy but....
here's the REAL question:
When is Mr. Gus Trim going to join our humble society? I'm sure he knows the great esteem in which many of our members hold his swords. I say ShooterMike should use his magical brownnosing powers (only joking ;D) to get Gus over here!
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Post by Deleted on Mar 25, 2007 23:41:02 GMT
I wouldn't count on having Gus with us any time soon (though I'd love to have him here too). It sounds like he's got a lot of irons in the fire right now, so to speak. If you'd like to try to speak with Gus on a more personal level than is possible on SFI, I'd suggest going here: www.tinkerswords.com/forum/. I've been a member there for some time, but I haven't been there since Paul started this forum. ;D It's a great place, though.
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Post by jw on Mar 27, 2007 20:18:14 GMT
Does anyone cryogenically harder their swords? It a new aerospace technique...
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Post by Deleted on Mar 27, 2007 21:51:03 GMT
Pardon me jw, but what is that?? Can you give me some information about that new technique? =x
-W.H.
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Post by Deleted on Mar 27, 2007 22:26:19 GMT
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Post by jw on Mar 28, 2007 0:24:31 GMT
The cryo process is you freeze metal to the point that the molecular matrix begins to align and condense, strengthening the material much like heat treating. Its done with liquid gas I think... Apparently you can extend the life of pantyhose by cryo'ing them, they will last for years... ;D I am a materials geek to say the least, of course I had to get the 9260 blade... Someday i'll make a tsuka and saya from carbon fiber, someday... Hell I could even do the tsuba too!!!
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Post by Deleted on Mar 30, 2007 3:05:17 GMT
I would expect the majority of authentic medieval & pre-medieval swords would start to land somewhere on the Rockwell B scale. (Way, way softer). (Iron Age, not Steel Age)
If you've got a professionally heat treated sword, worrying about the specific hardness number in the RC 48-54 range is splitting hairs. Confidence in the competance of the heat treater, and what they do on a daily basis- the company's reputation-, is where you'll want to focus your scrutany.
Swords going towards and even beyond the 60's is just an insane amount of hardness; I would be suspicious of such claims.
That's knife territory, and frankly, many knives will just snap; specifically the thinner blades.
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Post by ShooterMike on Mar 31, 2007 0:35:27 GMT
I would expect the majority of authentic medieval & pre-medieval swords would start to land somewhere on the Rockwell B scale. (Way, way softer). (Iron Age, not Steel Age) If you've got a professionally heat treated sword, worrying about the specific hardness number in the RC 48-54 range is splitting hairs. Confidence in the competance of the heat treater, and what they do on a daily basis- the company's reputation-, is where you'll want to focus your scrutany. Swords going towards and even beyond the 60's is just an insane amount of hardness; I would be suspicious of such claims. That's knife territory, and frankly, many knives will just snap; specifically the thinner blades. I agree completely. Any sword or knife meant for hard use would be very brittle if hardened to anywhere approaching HRC 60. I had one very hard knife (the brand escapes me) that approached HRC 60. The first time I tried to pry with the blade just a little, it immediately snapped in two without flexing at all.
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Post by rammstein on Mar 31, 2007 0:44:25 GMT
jphipps, I think you bring up another important issue that some amateur sword makers make the mistake of forgetting (or just not realizing). A sword is not a large knife. It has FAR different mechanics and details that seperate it almost entirely from a knife. Sure, it's made of steel. Sure it cts things. But thats about where the similarities end. Hardness, weights, taper, felxibility all have to be taken into account in an entirely different way compared to knife making.
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Post by Deleted on Apr 5, 2007 7:42:59 GMT
A sword hardened to 60 HRC seems like a bit of a dodgy claim, i dont know anything that would need to be such an extreme hardness, not even a performance level katana. I could be wrong though as i am only new to understanding these kinds of things. Cryogenically freezing steel with liquid nitrogen doesn't sound right to me as you can't slow freeze with liquid nitrogen and we all know that liquid nitrogen "deep" freezes things to the point where they shatter.
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Post by Deleted on Apr 5, 2007 9:15:37 GMT
lol that would be an awsome coreography trick to show someone shatter a blade with theirs of course that is if you didn't have to worry about shards of metal hundreds of degrees below zero flying through the air.
so to clarify for me as a new sword buyer (I currently own "sword like objects") such as myself I really don't need to worry about RC till i'm sword master extordinaire challenging 10 men at a time, looking for a custom forged sword I'm willing to pay thousands of dollars for, right? ok maybe I went a little over board but essentially not till I'm looking for "the sword" right?
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Post by rammstein on Apr 5, 2007 22:36:45 GMT
honestly...take sword hardness with a grain of salt, if you ask me. Once you know the good effective companies, buy based on what you like rather than what rockwell hardness it is. Of course, don't buy anything with a 40 rc for the opposite reason you wouldn't buy anything with a 60+ rc! But all of the prominent comapnies like gen2, windlass, cas iberia and even top tier makers like albion, atrim, and A&A all have a safe and useable hardness. Don't worry too much!
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Post by Deleted on Apr 6, 2007 5:21:56 GMT
thank you for putting it in lay mens terms for me. most of the post went over my head just wanted to make sure it wasn't anything I really had to worry about
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Post by Deleted on Apr 6, 2007 5:32:20 GMT
Cryogenic Freezing or whatnot is a silly way to say 'sub-zero-quench'. A quench is when you very rapidly cool a hunk of steel heated to a specific temperature. The temperature you heat it to and the rate at which you cool it determine how hard the steel is, among other properties based on the specific alloys in the steel.
Generally speaking, a more rapid cooling translates into harder steel(more technically means more of the steel grain structure becomes martensitic).
Sub-Zero Quenching refers to when you quench in a medium that is 'sub-zero' or 'colder than 0 degrees Celsius'. Liquid Nitrogen is one such medium, though i've only ever heard of knives being sub-zero quenched.
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