can you have a blade that will just not take an edge? UPDATED - Thank you forum crew!

Guys and Gals,

I am no newb to sharpening. I have been in this hobby for serveral years now, and own quite a few CRKs and several Spydercos, as well as some fixed blades. All my knives, excluding one or two, are daily users in rotation. All of my CRKs, including several Sebenza 21s, I can sharpen successfully, but one: my first 21, which is a standard point, micarta, made in 2012, S35VN. I have a few sebenzas of similar vintage (before the hardness upgrade) that cause me no grief. It is not that this particular knife takes an edge and then goes dull, it seems to simply not take an edge. It has been sharpened on rods (sharpmaker), loaded strops, and free-hand on a bench stone in my endless quest to get this knife sharp, but none of these techniques seem to work. My efforts with everything else I do are satisfactory.

So, my question:

Can a blade with some sort of metallurgy issue (too soft, too hard etc) behave in such a way that no sharpening technique will produce a nice shaving-sharp edge on it? Remember, I am not worried about edge retention, I just cant get a good initial edge on this one blade. Is it maybe a fubar blade?

 

So far, some really good ideas, so thank you all. I will try cleaning the stones and renewing my strop. Another thing I'll look at is if this 21, for some reason, is more obtuse that my others. On the metals side, I sorta wonder if this batch of S35VN was simply low on Vanadium, or the part of the ingot that made my blade was. IE: it has no carbides?

The ridiculous thing is after making this post, I was sitting effortlessly carving paper and shaving arm-hair with my Bark River Bravo 1 (also in S35VN), which is a giant chunky knife, and my old 21 can barely make it through a inch of paper without jamming up, and not much shaving.

I gotta get to the bottom of this. It's been bothering me for a very long time (obviously).

 

I appreciate you chiming in, but the point is not that I need this Sebenza razor sharp, just the observation that this one knife, out of my collection of 21s, behaves very differently than its brethren, and can't seem to take a razor edge, whether or not that's a requirement of my daily life.

 

More good advice. As much as it might pain me to purposely dull a knife I've struggled to sharpen, I will try your idea of discarding what I have and starting over.

 

Absolutely, and much appreciated. Over-explaining is never a crime on the CRK sub-forum. Thanks again!

 

A big THANK YOU to all my CRK pals who chimed in. You were right! I have a very sharp knife now, so I guess it was not a bum blade. Here is what i did and found out:

1: Taking the advice here, I stroked the blade about 8 times perpendicular, and firmly, to a white (fine) Spyderco bench stone (ouch!!). I verified that I could see light reflecting along the whole edge, indicating the old apex was no more.

2: I soon discovered that this blade was certainly hardened properly, as what I thought would be maybe 1/2 hour of work to restore the apex became something I accomplished over a couple evenings. I started using the brown Spyderco Sharpmaker stones on edge, at 40 degrees (inclusive), and began taking away the old steel, followed by switching the stones to flat, just as Spyderco recommends (being very very very careful not to let the blade tip slip of the corner when the stones were on edge). At this point the sharpie technique really didn't work because there was no apex to miss, if you know what I mean. The apex was basically squared off so the sharpening at this point was a process of narrowing the flat section I created by dragging the blade across the stone into a new apex

3: with the apex being flat, my guide for sharpening was looking for light to reflect off the edge. I set up a small task light at the prefect angle to see this. After an hour or so of carefully working the blade on the brown stones, I still wasn't completely there. I cleaned up the scratch pattern bevels on the white "fine" stones and called it quits for the evening.

4: on 'Day 2' I started in again on the brown medium stones (I do not own diamond stones or anything like that), and kept it up until I had a "ghostly" edge that would reflect no light. At this point I knew I was back at a 40 degree (inclusive) bevel.

5: I then switched to the fine and finally the extra fine stones, with extra time spent on each. Following that I stropped the blade lightly with a leather strop with fine (white) KSF compound. The blade was now shaving sharp.

6: I decided to slightly polish the shoulders of the apex bevel using the Sharpmaker set at 30 degrees (inclusive) and the extra fine stones. This just removed a little scratching and damage to that part of the blade from normal use of the knife.

THE RESULTS: HOLY SMOKES!!!!! Sharpest knife in my collection. All this time (years actually) I think I was fighting a weird convex edge, that I maybe aggravated through my own stropping, and perhaps some less-than-great steel on the edge from the factory sharpening process or heat treating. After many years of this knife disappointing me, it is finally, and truly, super sharp. I think also this blade is perhaps a little harder than the other 21 blades I have, so maybe it needed more time in the past to sharpen it that I was willing to invest.

Will it stay that way? Edge retention has never been my complaint on this knife, but I imagine, like any S35VN, the nice edge i put on will quickly dull to a durable "working edge" that will last a long time. It is nice, however, to see this knife truly sharp for the first time in it's life. Thank you to everyone who pushed me to start over. That was the best thing to do.

We are now s-cutting paper with a quiet swish, shaving arm hair, and reflecting light like a mirror, with this crazy edge. I love it!