Can you sharpen pe H1 enough to increase edge retention?

T

timbo813

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Jun 24, 2014
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It seems to be well established fact that serrated H1 has better edge retention due to work hardening in the grinding of the serrations. So, if that is the case, can you sharpen a plain edged H1 knife enough to increase the retention?

I really like my se salt1 but I prefer pe knives. Just wondering what the edge retention might be like after some time on a work sharp.
 
I don't know about that blade material but I think the term you are searching for would be "burnishing". Burnishing compresses and moves the metal into a sharper edge (if done right). Usually most sharpening we talk about here is abrading, i.e., removing metal with sharp/super hard abrasive media.
 
H1 is work hardened, which i don't think can be achieved on sharpening stones. Apparently it is hardened while grinding, so maybe if you sharpen on a belt grinder? I think Sal might be the only one qualified to chime on on this.
 
shipwright said:
H1 is work hardened, which i don't think can be achieved on sharpening stones. Apparently it is hardened while grinding, so maybe if you sharpen on a belt grinder? I think Sal might be the only one qualified to chime on on this.
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Well I am talking about doing it on a work sharp which is basically a belt grinder. I've heard people theorize about this before but not anybody who has actually done it.
 
There are a lot of mixed opinions on this one and I have asked many people including a few members of Spyderco's staff. It is a fact that H1 work hardens but whether or not it happens during hand sharpening is the question.

On one hand, the serrated knives are much harder than the PE knives and they are both ground with power equipment. Apparently grinding serrations hardens more than grinding a straight bevel. If this is true then you should get even less hardening from hand sharpening. On the other hand, nobody has the ability to measure hardness directly at the apex itself and the hardening we are talking about may not penetrate very far into the knife (think in microns) so how would you be able to know? What happens at the apex itself during sharpening is a bit of a mystery. There are people who say that hand sharpening on a dry stone can produce temps of 2000 degrees at the apex itself (think in microns here) almost instantly and some argue that is not true. If you are using a course stone you may very well be removing any metal that has been hardened (or annealed if the temp thing is true) as fast as it is created. At lower grits you may be doing less abrading and may achieve more work hardening. If you use a steel and reshape and edge instead of abrading a new one it seems like you may also achieve more work hardening and you aren't abrading any away.

I have no answer to this one but it has always intrigued me. The forum world seems to have mixed opinions. I doubt that it would produce any beneficial amount of hardening but my experience with H1 is limited and I just can't say for sure.
 
The real issue is how do you measure hardness at the apex itself or at least as low on the bevel as you can. I don't believe that there is an easy way for anybody to do that so our answer may very well go unanswered until somebody figures out how to measure it and then shares it with us.
 
Hi Timbo,

Some H1 users swear that they are getting improved edge retention with repeated use and sharpening, but we have no way to verify these results. As Killer mentioned, measurement is difficult.

I can't say that I would recommend power sharpening as you will remove a fair amount of steel.

sal
 
I have tried using pe H1 and it is just a bit low in edge retention for my uses.

Here's an interesting observation. I can even note a big performance difference between the pe tip of my Pacific Salt and the serrations. The serrations hold their bite quite well (even the tips of the serrations) while the pe tip goes dull after push cutting 8 or 10 pieces of 50 pound monofilament fishing line. I mean dull to the point that the edge will actually roll. I have never experienced any significant rolling issues with the serrated portion though. Weird stuff.

Edit: I meant to add that I have sharpened the pe portion of this knife HUNDREDS of times and have never seen any increase in hardness or edge retention.
 
Wowbagger said:
I don't know about that blade material but I think the term you are searching for would be "burnishing". Burnishing compresses and moves the metal into a sharper edge (if done right). Usually most sharpening we talk about here is abrading, i.e., removing metal with sharp/super hard abrasive media.
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That's an interesting concept "Wowbagger" because that coincides with a sharpening question I've had for some time now. When it comes to "burnishing" which is a term I've heard used in many contexts over the years especially in the machine tool sector>> but what I would like to know is what we call "steeling" a knife with a sharpening steel or what many in the meat cutting industry refer to as a "butcher's steel" >> it boils down to this question I've had for a long time>> Is "steeling" a knife blade edge a form of burnishing? Because I do know that the term burnishing has many different applications to it.

I find that either steeling or burnishing H-1 blade steel could be totally different than steeling or burnishing other blade steels because H-1 steel is known as a "work hardened" steel. I've had decent results steeling other blade steels but H-1 without a doubt has different properties and I do find it interesting to workwith.
 
Sal Glesser said:
Hi Timbo,

Some H1 users swear that they are getting improved edge retention with repeated use and sharpening, but we have no way to verify these results. As Killer mentioned, measurement is difficult.

I can't say that I would recommend power sharpening as you will remove a fair amount of steel.

sal
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You know out of all of this talk of H-1 blade ( which I like by the way) the one fact that truly baffles me is the sterling results that there have been many claims of H-1 being one of the better steels you all have used in Spyderedged (fully serrated). I know I've had great luck with the full SE, H-1 folders I own. It's truly interesting what properties in blade steels make for better serrated edge performance. Also I'm wondering if you all at Spyderco have tested the other Nitrogen based LC200N steel that you all use in the TUSK model as to whether or not it performs well in Spyderedge?
 
+1 on all that

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I EDC'd my Pacific Salt literally every day for the last 6 months or so, and found that the PE portion got dull much quicker than the serrations.

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I've sharpened the PE many times (60-80) during this half year and I've cut zip-ties, cardboard, rubber, plastic bands, a bit of really soft wood and food during this time.

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Used Smith's 1000 grit, DMT Coarse and Fine and also both Sharmaker Brown and White rods.

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The serrations stay sharp much longer, no doubt.

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And I haven't found any improvement in the plain edged section, either.

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That's all I can say!

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PS: I forgot, I also sharpened it on a curb (that cement-material-like leap from the roads and streets, however it is called in English) after the Pac Salt fell and blunted the tip badly, minutes after taking the above pic. I kinda repaired it until I got home and got it pointy and shaving sharp again with the SM.
 
I've never noticed an increase in edge life from repeat sharpenings. I still like plain edge H1, but I also realize I'll be touching up the edge more often.
 
One day, many moons ago, I was speaking with a very bright man named Peter about H1 steel and why it has the edge retention it does. Now, I have never used H1 but was intrigued and a bit confused as to why the serrated blade had the claims of greater hardness and extreme edge retention. It was explained that H1 is about double its thickness before hardening and to harden the steel it is rolled through rollers under ton's of force compressing it's thickness by about half.

It was said to me that the steel is harder towards the surface and softer in the middle after this compressive process. Because the serrations are asymmetricly ground they are ground into the harder section of the steel. For the plain edge versions the edge is ground in the center of the blade so it's in the softest part of the steel.

IMO, this explanation makes the most sense.
 
Jason,

Thank you. That might be the reason.
Some interesting observation on above posts:
The plain section of a full SE Pac Salt is also ground to one side of the blade. However, it's noted that it still has less retention than the serrated part.
This doesn't seem to follow the explanation. Perhaps there're other factors at play?
 
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I held a Pacific Salt SE yesterday and liked it more than I thought I would. Seems like the H1 steel and SE go well together. It was probably the first knife that made me want a serrated edge. Damn my sister for having a whole show-and-tell box of Spydies I had not seen in person before, and she showed me lots of H1. The Salt 1 PE didn't do anything for me. There's a Delica in my survival "bugout bag", but the choice of Pacific Salt SE for hers is hard to find fault with.
 
Burnishing tools are cheap. If you use one on a plain edge, the pressure used is much greater than what would be used on a steel. Orient the knife edge on the edge of a table so much pressure can be applied with the tool, and do both sides of the blade.
 
Chris "Anagarika";15629805 said:
Jason,

Thank you. That might be the reason.
Some interesting observation on above posts:
The plain section of a full SE Pac Salt is also ground to one side of the blade. However, it's noted that it still has less retention than the serrated part.
This doesn't seem to follow the explanation. Perhaps there're other factors at play?
Click to expand...

Possibly,

I have never used it myself so I have no data points of my own. I simply find it interesting that it's compressed so much and had no actual HT. Beyond that it's always been a big mystery.
 
I think one reason that I have trouble with the pe tip on my pacific salt is almost certainly due to the edge angle. The chisel grind is about 15 degrees on one side and whatever the primary bevel angle is on the other...certainly no more than 5 degrees. So the tip has an edge bevel that is about 18-20 degrees inclusive. I just don't think that h1 is quite able to hold that angle.

The dulling I get at the edge is almost always from rolling. Now that I'm thinking about all this I'm going to start sharpening the tip differently. Until now, I have only sharpened the ground side and simply removed any burr from the flat side. I'm going to start putting a full 40 degree microbevel on the tip and see if that stops the rolling and changes the performance.
 
Lance,

Have you tried the 40° inclusive?

I have only one Pac Salt and this weekend reprofiled it to approximately 30°. What I observe is that once the bevel is polished with worn DMT EEF, and then Spyderco UF, it seems to tend to glide, as if on glass and difficult to remove more steels from it. I had to go back one step, using DMT EF, get a burr, then only progress again to EEF.

Someone mentioned it's wear resistance is closer to 154cm and better than AUS8. :confused: I'm still testing it.
 
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