Hey all. I have a question today regarding sharpening. I have a sharp maker, and consider myself a decent novice. I can get blades hair popping easily. However, I am having one problem. I have a certain knife, a Kershaw brawler, that I can get sharp. I don't want anything sharper than hair popping, so that's what I have. This is a knife I carry riding free in my pocket all day every day. However, when I take it out after little or even no use, i realize it can't even shave. It is still sharp to most people's standards, but dull to ours. Any tips or ideas here? I don't know what I'm doing wrong or not doing at all. I believe it is 8cr13mov.
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Knife dull in pocket
- Thread starter nlewman
- Start date
- Joined
- Sep 23, 2014
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- 1,287
Sounds like a burr
or just fatigued/damaged metal
either damaged from previous use,
or burnt from power sharpening without coolant
Solution is cut off the existing edge
by cutting into one of the sharpmaker stones at 90 degrees
to make it nice and reflective
and then sharpen it as usual
Its commonly reported it takes until the third sharpening before you're dealing with good undamaged steel
or just fatigued/damaged metal
either damaged from previous use,
or burnt from power sharpening without coolant
Solution is cut off the existing edge
by cutting into one of the sharpmaker stones at 90 degrees
to make it nice and reflective
and then sharpen it as usual
Its commonly reported it takes until the third sharpening before you're dealing with good undamaged steel
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- Apr 12, 2009
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- 13,401
Yes, likely a burr. The edge geometry behind the apex might also be somewhat thick. It's a common behavior for a thickish edge with a burr that folds over; it'll stop cutting in it's tracks.
On the Sharpmaker's ceramic rods, it's of paramount importance to keep pressure very, very light in the finishing strokes, to minimize any burrs formed and also to prevent forming new ones. It's very easy to leave a burred edge if pressure is just a little too heavy.
David
On the Sharpmaker's ceramic rods, it's of paramount importance to keep pressure very, very light in the finishing strokes, to minimize any burrs formed and also to prevent forming new ones. It's very easy to leave a burred edge if pressure is just a little too heavy.
David
- Joined
- Jun 4, 2010
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- 6,642
How are you sharpening it? Avoid the strops for now if you aren't already.
Next, examine it after opening and closing if it has a a solid backspacer - anything it might be contacting when it is closed.
Edit to add: off the SM I'd have to agree its likely a burr or wire edge...
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If it is a pillar constuction with an open back, it may be the coins, keys, etc. are hitting the blade even closed in your pocket. I carry either a Kershaw Crown or Drone; both open back pillar construction, but they are all I carry in that pocket. Just a thought.
Rich
Rich
I have been trying to remove the burr before I sharpen. I pull the blade lightly across a stone until it is nice and reflective. Last night while trying to sharpen it (again) I realized that the bevel is more than 40 degrees. I have to use the sharp maker at an angle. The knife is half open and half solid backspacer, but there is not noticeable difference in sharpness on either half.
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That'll present the most trouble in trying to attain shaving sharpness, even without a burr. It may be what's creating most of the trouble in the first place. A 40°+ edge has to be nearly perfect to shave; even then, it wouldn't likely hold that kind of sharpness after much real use. Once the apex wears just a tiny bit and loses it's crispness, the shaving sharpness will disappear again with only the wide edge geometry left behind. If still wanting to make it shaving-sharp, and keep it that way for a while, thinning the edge down to ~30° inclusive or lower will help get it there, and it'll be much easier to maintain sharp. That should likely be done with a coarse stone or with the optional diamond/CBN rods for the Sharpmaker, if choosing to pursue it.
David
Last edited:
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- Jun 5, 2009
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- 1,126
This would be one of my thoughts. The other: the ball detent is weak and the knife is coming open in the pocket and the edge is bearing on other things you're carrying. I had exactly that problem with a CRKT KFF. That was a combo of weak ball detent, AUS6 sub-par steel, and CRKT's Nev-R-Sharp heat treatment. I found out about the ball detent last when I went to get keys out of the pocket and the knife came out imbedded in my finger.