Sharpening S30V, and some surprises.

The Tourist

The Tourist

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Dec 23, 2001
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I decided I was getting just too anal about my edges. Several months ago I switched from mirror-polished Microtechs, to heavy duty Striders. I also quit looking at these fresh edges with a lighted loupe all of the time to check for minor dings. I'd sharpen the edge so it cut a variety of things, and then left it.

My Strider AR and my SnG were the first knives I ever had that were made from S30V. Both Lynn Little and I noticed tiny white 'flat spots' in the edge; we didn't know if we had bumped the edge, or if this was from some type of fracture.

A week ago, I sharpened my SnG; it didn't really need it, but I touched it up. As I pulled this fresh edge through some newsprint, the edge caught and lightly ripped the paper as if the edge was ragged. Against my better judgement I checked the edge with a lighted loupe; sure enough, there were these little flat spots again, this time like a little string of pearls. I stropped the edge, it improved but wasn't perfect, and I put the knife away in my pocket. No more anal behavior.

Last night while reading a new car magazine, I took one of those blow-in subscription cards, and started to shave off strips. It started rough, and then after about 20 strokes, it got really smooth. I checked the edge again under the loupe, and lo and behold, the edge was perfect!

I've never had a steel that did that. Sometimes, you can knock a wire edge off on cuts through cardboard, but paper actually stropped this edge.

Anyone else have this happen?
 
Not yet. My Benchmade 921 sharpens and cuts well and my Spyderco Native sharpens excellently and cuts like a very thick spearpoint with a hollow grind. Also haven't noticed the chipping others have reported.
 
Ichabod,
Actually, many makers sharpen to a burr, then make a few passes through cardboard or paper to knock off the wire edge. Same thing stropping does, but it will take more with S30V and in my case S90V. :cool:
 
S30V is one of my to favorite steels for the knives I make. I harden and temper for HRC 61. After grinding I set the bevel with a fine DMT hone, then finish with a surgical black Arkansas stone followed by a translucent Arkansas and then strop on hard leather glued to a wooden block. The result is the finest, smoothest edge I have ever seen (I also use a loup). Properly done this will slice paper towel. You do have to put extra effort into getting the last wire off the edge.
 
Shgeo,

I'm sure that if I returned to my old anal ways I could easily polish the edge so that it sliced anything. As I once stated, several of my friends and I used to 'razor-mirror' our Microtech USSOCOMs to see who could get the sharpest edge. Of course, we never used the knives to cut anything in the real world, just in ouir competition.

It seemed the waste of a good knife. I promised myself I just wouldn't do that with my SnG; it was to be an true EDC. I'd sharpen it on the Edge Pro, use it, and if it got dull, it would go into the pile of 'knives for the Sunday sharpening.' No worries.

I don't think these 'white spots' are fractures. They appear flat. Sometimes you get them, sometimes you don't. I originally thought they were from hitting a rivet in the handle when closed. But I get them during sharpening sometimes.

I just want to re-sharpen with the 220 or the 320 stone, and then just touch it with the 4000 series tapes or a few licks of a horsehide strop. Sure, it's VERY sharp, just not as perfect as those USSOCOMs. I just cannot tell what I'm doing to create those spots.
 
I have seen blades sharpen with use, it can happen due to the way in which the wear is induced, some posts were made on this in the review section. In general you see it more with very coarse edges on large grain steels. This doesn't sound like what you described though. It could be as simple as grit on the edge getting cleaned off.

In regards to removing a burr by cutting cardboard, this isn't a good idea. A burr is a mix of steel and abrasive debris and will abrade the other parts of the edge as it breaks away and gets into the material being cut. As well as it breaks away it isn't going to for a very clean edge in regards to being cut away with a hone.

Bright spots described as in the above on an edge visible after honing are often caused by edge having not been formed properly from the maker / manufacturer. Specific to Striders, both the PAB and WB I had were like this initially. The only way to remove them it to completely hone them out.

-Cliff
 
IP,

Not sure if this is relevent to the issue, but I haven't had that problem with my S30V. I've used Microtech S30V and Strider/Bos S30V, with no dips or white patches on the edge. (Admittedly I was only looking with a 4x loupe.)

With my S30V, I usually do the following: Sharpen/reprofile with the 100-grit, working my way up the ladder until the 400 (?) and 600 grit stones. Strop a few times on cardboard, and then on a leather belt. Nice, toothy yet slicing-happy edge. No burr problems, no dips in the edge.

440V, on the other hand... I was never able to break off the burr with that stuff with stones. Just bent it back and forth. I ended up taking a diamond rod to it at a higher angle than I sharpened at to get rid of the burr, and I could never get the edge so it sliced properly. Not terribly fond of that stuff.

-j
 
Cliff and Biogon,

After speaking with Lynn Little, it appears that it happens primarily to newer knives of S30V. As I've stated, it's easy to see and fairly easy to polish out. It happened several times to my Strider AR during its first two sharpenings, but has not resurfaced after the third sharpening.

I use an Edge Pro. Just to eliminate any problems with the stones, I straightened them all in some finer grain silt that Ben Dale sent me. No burrs in the stone.

What bothers me is that I'm anal again. Most new knives have some type of uneven area on a bevel, and they never touch the stone with the first few sharpenings. I don't grind metal senselessly, and I have a light touch. If these flat spots wouldn't tear paper, I'd let the issue go.
 
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