Razor Sharp to Scarey Sharp

B

Brian6244

Joined
Aug 25, 2004
Messages
537
There are two particular knives in question: The first is a CRK Shadow III in A2 and the second is a CRK Large Classic Sebenza in S30V. With my trusty Sharpmaker I can bring both to razor sharpness but I can not seem to achieve the hair popping sharpness that I believe is know 'round these parts' as scarey sharp. After reading several past threads I have tried stropping on cardboard with no success. I have also gone out to the local auto parts store and purchased a few sheets of 2000 grit sandpaper which seems to actually dull the knife rather than sharpen it. Help! Thanks! :D
 
Perhaps you need a steeper angle. What are you at now?
 
Well, 20 degrees per side gives you a combined blade angle of 40 degrees ...which is just slightly under 45 degrees ...or half of 90 degrees (i.e. a right angle). Not exacly a 'fine' edge, now is it? Heck, I've got chisels with a finer edge than that :)

Instead, try something like 11 degrees per side, for a combined edge angle of 22 degrees ...much better for attaining a keenly sharp edge. Keep in mind that many chefs recommend that kitchen knives be sharpened to about 5 degrees per side, so actually 11 degrees is more of a 'middle ground' when it comes to blade angle geometry.

Just my $.02 worth :)
 
When you strop on leather/cardboard/whatever - you need a higher angle than what you had at the stone.

But that may not be the problem. You may still not have done enough fine polishing at the med. high grits (800-2000).

Further, D2 and S30V are notoriously difficult to polish in the first place...so you may be fighting a losing battle.

Be grateful for your toothy edge - it will last a long time.
 
I've seen significant improvement by going from 40 to 30 degrees, but that was on a pretty thin ATS34 blade. Any reprofiling of S30V, without a diamond hone of some kind, is going to be a lengthy she-dog of a process. You'll hit 30 along the way to 22 (as jiminy suggests), so you may want to stop there and see if you're happy. Or, as DK suggests, get happy with 40.
 
I had this same problem with a cardboard strop. I have no problem sharpening my Gene Ingram hunter (D2) to that level of sharpness with a leather strop and compound. Raise a burr with a stone, then strop (at a higher angle) till the burr is gone.
 
jiminy said:
Instead, try something like 11 degrees per side, for a combined edge angle of 22 degrees ...much better for attaining a keenly sharp edge. Keep in mind that many chefs recommend that kitchen knives be sharpened to about 5 degrees per side, so actually 11 degrees is more of a 'middle ground' when it comes to blade angle geometry.
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This is thinner than I have tried and to be honest I'd be nervous going that thin. With an edge that thin, with a quality steel like VG-10, S30V, etc, what would you be comfortable cutting with it? Would you be limited to fruits and veggies on a cutting board? Could you take that to cardboard, rope, etc and not worry about chipping the blade?
 
WadeF said:
This is thinner than I have tried and to be honest I'd be nervous going that thin. With an edge that thin, with a quality steel like VG-10, S30V, etc, what would you be comfortable cutting with it? Would you be limited to fruits and veggies on a cutting board? Could you take that to cardboard, rope, etc and not worry about chipping the blade?
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Ya I wouldn't even consider going below 30 degrees. To tell ya the truth I would really prefer to stick with 40 but I guess I'm being told that scarey sharp is just not possible with A2 or S30V at 40 degrees. Seems a bit odd since Chris (Reeve) sent them both to me with hair popping sharpness, but then again I'm sure he used a paper wheel and/or a buffer wheel both of which I do not own. :) I do also think based on what I have read so far that my stropping technique has been flawed so maybe correcting that will help too. I guess I'll just forget about the 2000 grit sandpaper, atleast for now.
 
A well polished edge will still shave. I've seen axes and hatchets that shave. They just wont slice well
 
Brian6244 said:
Chris (Reeve) sent them both to me with hair popping sharpness, but then again I'm sure he used a paper wheel and/or a buffer wheel both of which I do not own. :) I do also think based on what I have read so far that my stropping technique has been flawed so maybe correcting that will help too.
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Chris Reeve sent them to you with a deep hollow grind and a convex secondary bevel. A Sharpmaker will convert this to a flat secondary bevel.

You can try to approximate the original edge by following up your 40 degree work with a 30 degree. This will smooth the transition between the top of the secondary bevel and the hollow grind.

Also be sure when you finish off your sharpening on the white rods, you do so with extremely light strokes.
 
I would try using a 15 degree per side (30) angle until it almost shaves.
THEN, use the marker trick. Color the entire beveled edge with a sharpie (rubbing alcohol will easily remove).
Then when you do a few strokes at 20 degrees per side, you should see that the marker is removed at the very edge. If it is, then you can hone at 40 until it shaves.

You may not be hitting the very edge consistenly? The Marker trick helped me immensely.
 
Brian6244 said:
I guess I'm being told that scarey sharp is just not possible with A2 or S30V at 40 degrees.
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It's entirely possible! You can get scary sharp with an even larger angle. When using your Sharpmaker, apply a medium-to-almost-heavy pressure when you start on the brown corners (at 40, this should be safe; at 30, it may cause edges which are too thin, soft, or weak to chip). As you near the end of the amount of alternating strokes, ease up on the pressure. Before you switch to the brown flats, perform about a dozen very light, alternating strokes on the brown corners. The blade should now be quiet sharp (at least in terms of shaving hair off of your arm). If not, try another dozen or so very light, alternating strokes. If not, go back to 40 alternating strokes on the brown corners starting with medium pressure and ending with fairly light before repeating the 12 gossamer passes thing.

Repeat that same technique for the remaining three steps (brown flats, white corners, white flats). It's not something you'll pick up immediately, but it will work.

There's no need to use a < 40 degree angle if you're not comfortable doing it. Thinner angles do reduce the amount of force needed to cut (a dull knife at 20 degrees can often outcut a sharp knife at 40 degrees), but they increase the chances of your knives dulling from the edge rolling or chipping. I still do it, but, to me, a damaged edge is more fun with my sharpening tools.
 
Excellent advice. I followed your instructions to the letter and has drastically increased the sharpness of this fine blade!!! Thanks!!!
 
Congratulations and welcome to the world of sharp. ;)
 
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