Longest razor edge holding steel on production knife?

chiral.grolim said:
What grit do you sharpen to? Are you leaving a wire-edge that is folding over after the first few cuts? Lots of great advice in the Maintenance Sub-forum for getting the most out of your edge.

I have a CalyIII in ZDP-189 that holds its edge noticeably longer than a number of my other knives in "lesser" steels, but my favorite for breaking down boxes is a utility knife by Tim Johnson (timos- here) of Black Stone K&T. That blade is AEB-L @ ~60Rc with edge-geometry to make it shine: now ~0.006" behind the edge with a very thin flat (very slightly hollow) behind that up to the ~1/8" spine. The sturdy spine keeps it stiff and comfortable to control, the thin edge makes for easy penetration. In Jim's testing thread, coarse-section (linked below, but everyone knows it, right?) you can read where ZDP-189 in normal Spyderco geometry performs (~420 cuts); a little ways below is a measure for AEB-L (340 cuts) - that is the exact knife I sent to Jim for testing. Does it hold its edge as well as the Spyderco? No. But the thin geometry cuts with such ease, that reduced effort is enough to keep me picking the timos- over it for such a task, plus the narrow bevel requires less metal-removal to restore the apex as needed.

http://www.bladeforums.com/forums/s...based-on-Edge-Retention-cutting-5-8-quot-rope

A video of the timos- and the CalyIII (at 14:20, no need to watch the whole thing):

[video=youtube;rEIX7pMSTHo]https://www.youtube.com/watch?v=rEIX7pMSTHo[/video]
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Thanks for the info and links!

I think I always end up with a tiny bit of burr on one side of the blade, but it can't be seen and can barely even be felt. I thought that if you ended up with a true wire edge then only one side of the blade would be sharp, whereas mine are shaving hair with both sides when I'm done sharpening.

I use a sharpmaker. Diamond rods to reprofile, then browns, and whites to finish. Very very light pressure for the last few strokes. No stropping tho.
 
ejames13 said:
That's impressive. What method did you use to sharpen those? Do you strop? My Spyderco DF2 (in ZDP-189) loses its ability to shave after cutting through just a few boxes. I must be doing something wrong.
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DMT plates up to 625 and then then a few passes at 1200 to make the grinds look good. Then I strop them on dia-paste loaded strops until they get that feel like they're catching every cell of my thumb.

Whenever I feel like they've lost it I strop them back and cut stuff up all over.

The Gayle Bradley is just under 15dps and the Contego is around 18dps. Both are awesome. Their steel holds up well to abuse
 
I think an INFI knife made over 1,000. cuts on hemp rope before it lost it's bite.
rolf
 
NetshadeX said:
CPM10V on my K2 is probably the most impressive steel I've come across when it comes to edge holding. That stuff outright refuses to go dull.
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I've been wanting to try out 10V. Just waiting for the 4" K2 to become available.

Anyway , I have found S90V to hold an incredibly sharp edge for an impressively long time with moderate use.
 
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Whatever steel Gillette use will hold razor edge longer than any steel mentioned here...
 
ejames13 said:
Thanks for the info and links!

I think I always end up with a tiny bit of burr on one side of the blade, but it can't be seen and can barely even be felt. I thought that if you ended up with a true wire edge then only one side of the blade would be sharp, whereas mine are shaving hair with both sides when I'm done sharpening.

I use a sharpmaker. Diamond rods to reprofile, then browns, and whites to finish. Very very light pressure for the last few strokes. No stropping tho.
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The grits on the SM are ~800 brown and ~1200 white? I use a 1200 DMT plate for most of my touch-ups as seen in the video. Your technique is sound, as long as you are holding an appropriate angle to sculpt the very apex, and a shaving-edge from either side indicates success :thumbup: But a wire-edge, depending on the foil created, can waver from side to side along the apex, it could be that you've created such an edge that crumbles or folds upon harder use than shaving *shrug* Are you using the points or the flats of the SM rods? If you finish by stropping on bare denim or leather or something similar to act simply as a "burr-catcher", that may help, but only if a folding edge is the problem *shrug*. Cardboard, especially thick stuff, is harsh and irregular, it'll squash a soft edge and fold a thin edge in a hurry. Here is an image from ToddS's blog showing the edge of an H1-steel blade at 20-dps after cutting 20' of thick cardboard: https://scienceofsharp.wordpress.com/2015/01/13/what-is-a-burr-part-2/

Before:
delica_250nmroo_01.jpg


After:
delica_cardboard_02.jpg
 
Great info Chiral. To that I'd only add that something I saw often in kitchens was that people didn't strop enough after touch ups. I used to have to emphasize the heat you're trying to generate in order to remove that burr. Those photos tell a 1000 words though. Thanks!
 
The old kershaw shallots in S110V are pretty awesome; thin blade + great steel...

M390 & M4 are pretty awesome too. ;):D:thumbup:
 
The issue of best steel and which one holds and edge for which task is a very complex subject that this forum has struggled with on many occasions; more to come. My question is more along the line of heat treat; does anyone have any information on manufacturers heat treat processess as this is where all steel gets its true strength. For example how does s30v from company "x" compair to s30v from company "y".
 
marsalla said:
... My question is more along the line of heat treat; does anyone have any information on manufacturers heat treat processes as this is where all steel gets its true strength. For example how does s30v from company "x" compair to s30v from company "y".
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Well, Crucible is the only manufacturer of S30V and they offer a suggested HT protocol on the datasheet: http://www.alphaknifesupply.com/Pictures/Info/Steel/CPMS30V-DS.pdf

Buck HT's S30V and other steels using the proprietary Paul Bos protocols, CRK uses AceCo heat-treatment, Peter's HT probably has their own protocols... Most knife companies do NOT do their own HT, they contract it out, and I'd guess most HT companies have their own proprietary protocols based off of the manufacturer recommendations, so information may be limited to the final hardness and whatever little details the makers will share to try and promote their product... I hear Phil Wilson does a pretty good job HT'ing his own knives :)
 
This is what I was getting to; you can take batch of s30v and send it to five different companies for HT and you will end up with steel that could have different properties.
 
I must say I am thoroughly impressed with Fallkniven' s laminated cobalt steel and 3G as well. Both take and hold a fantastic edge.
 
SG2 is the sharpest I've come across. Its hard to tell you what will last the longest, because at 10 dps edges don't last long. I think its more about the heat treat at that point. Its a real trade off between edge holding and sharpness attainable. A steel with great wear resistance wont be able to get as sharp. I've found CPM D2 to be a great median.
 
marsalla said:
This is what I was getting to; you can take batch of s30v and send it to five different companies for HT and you will end up with steel that could have different properties.
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Honestly, you will also see differences in the indicidual blades in those batches from eah company in most cases. If a company has a heat treat that is done in larger batches, then some blades will have trouble and some won't, and that variability means that the differences between most companies will be lost on the differences between their own blades and the ones treated by their competition.

Essentially, unless we are talking about a small-bath company or custom maker than heat treats in very small batches to a very precise protocol and end result, the differences will not be apparent enough in general to really notice most of the time. There will of course be exceptions, but the difference in the blade shape and grinds, combined with the variables in heat treating, will usually hide almost all of the differences.

The exception would be a company that uses a different overall methodology to heat treat. For example, when you compare CRK's S35VN to other companies, CRK runs it codger and heat treats in smaller batches, so it is INTENDED to have different properties that other companies.
 
DeadboxHero said:
Hey guys,

There is a lot of advances steels out there that hold edges for a long long time but the razor( hair shaving) sharpness seems to go away just as quickly as it does on average(aus8) to above average(s30v) knife steels.

Are there any super steels that hold that razor edge the longest vs just edge holding?

Thanks guys
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This is the characteristic of steels with high amounts of carbide formers, any time you have a "wear resistant steel" it's fine edge holding ability pretty much sucks.

ZDP-189 is probably one of the only steel listed in this thread that would meet your requirements. With responses like S90V, 10V and S110V (some of the most wear resistant steels on the market) I'm not sure the audience fully understands your question as they seem to be giving you exactly the opposite of what you are asking.
 
So back to heat treat. I assume that big companies have some sort of test process when they heat treat large numbers of blades in a batch. That would be strange to find one or more bad blades from a batch reach the consumer market.
 
DeadboxHero said:
Hey guys,

There is a lot of advances steels out there that hold edges for a long long time but the razor( hair shaving) sharpness seems to go away just as quickly as it does on average(aus8) to above average(s30v) knife steels.

Are there any super steels that hold that razor edge the longest vs just edge holding?

Thanks guys
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What are you going to be using the knife for?

There are just way too many variables to really nail down one answer or just one steel etc.

Very narrow and a very short part of the dullness slope you are asking about here.
 
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