WSKO: some knives not as sharp as others

C

chado skins

Joined
Jun 25, 2014
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33
so i got the WSKO, and sharpened a bunch of my kitchen knives. some of them had a edge put on them about 3-4 months ago buy a knife shop. not sure what kind of machine they used, the guy said it costs 40K if that means anything (probably bull). when i ran the knives through, the ones that were previously sharpened in the shop came to a great edge. but the others, one dulled out beater, two new henckles, not nearly as sharp. i started the three that didn't come out as sharp again through the progressions of belts thinking i didn't spend enough time... i got burs on the initial belts... they just don't feel nearly as sharp as the others. am i doing something wrong? is this par for the course? thanks for any replies!
 
You got initial burs, so you hit the apex right? The apex if you are unsure, the grind goes all the way to the edge.

Another thought, just my opinion though. You may be grinding a micro-bevel on the pre sharpened blades by using to great of an angle. It may not be as noticeable because of the convex the WS is producing. The other knives that you are having trouble with may benefit from a more acute angle ground to the apex and then refined with the finer belts. Light pressure with the fine belts have proven to produce sharper blades for folks using the KOWS.
 
I sometimes notice this as well. I can always get a knife hair popping, paper pushing sharp but… can't cut a tomato (see semi-famous thread from BF past). It will of course cut a tomato but it does not have any bite. I am trying to get toothier edges on my knives using the KOWS but lack experience. I am trying the following:

1. Slower speeds, slower pulls
2. Smaller angles
3. Hand strop (don't progress past X4).

Don't get me wrong I am very happy with the KOWS and can get my knives very sharp. I know it has a lot to do with blade geometry. I used to use a guided stone system (Gatco) and got ok results but my technique is overall poor and I am a lazy sharpener. This laziness has transferred to the KOWS as well and I am now forcing myself to pay closer attention to pull, angle and technique with much better results.

I also think I may be pushing the blade against the belt in the belief that my issue was poor and inconsistent contact. I think this is wrong after reading another post about the KOWS. I am going to go for the straightest, lightest pull I can and see if that helps.

AGAIN, even with all my sharpening shortcomings my knives are sharp and can when needed can get them that way very in no time. Can't stress how much I love the KOWS. I strop by hand all knives after use (Black, Green and Bare). I would like to be able to put a very toothy edge (think new Case edge) that will rip into what I am cutting but have not figured out how to do that on KOWS or any other method.

There are some great threads on the KOWS on here already and I imagine some great tips may come out of this thread as well. I ofter wonder how the angles on the KOWS convex edge match up to a more traditional micro bevel or straight V angles achieved by other methods. Anyone?
 
I have found that the sharpness of knives sharpened on my WS varies as you say. There doesn't seem to be any pattern for me, I chalk it off to user error:rolleyes:
 
We do need a thread on techniques for WSKT-KO or KOWS. I have experimented with lighter pressures (weight of the knife) and seem to be having better results. I'd like to hear more from others.

Good sharpening,
Dave
 
cschol, i think you may be onto it... i was thinking along the same lines. the pre sharpened knives have a fairly long back bevel running up the spine. when i resparpened them, you can see the new front bevel, then it goes to back bevel, then tapers back. i'm thinking i need to spend a little more time with the less than sparp ones on the courser grits. maybe do a double bevel on them? 15 back 20 primary i've seen floating around is fairly good for kitchen knives...

when doing a double bevel, do i start with the coarse grit 15, then 20, then medium, 15, 20, then fine 15, 20? or is it like 15 on coarse, 20 medium etc... thanks for the input guys!
 
If it were me, I would just take them to 15 and be done with it. If they are all the same angle, maintenance will be simple.
If you want 20 degrees, I would do 15 first all the way to fine, then 20 to fine. That way your scratch pattern will not be different.
 
With blunt knives you will have to re-establish the bevel. once you do they will be fine.

More runs with the coarser grit to establish the bevel...
 
pap11y said:
With blunt knives you will have to re-establish the bevel. once you do they will be fine.

More runs with the coarser grit to establish the bevel...
Click to expand...

THIS^^^ I learned long ago and far away, that most folks don't start coarse enough or go long enough with coarse before moving to finer.
 
you don't think 15 degrees is too narrow for euro style knives/steel? i put a new edge on a jap steel knife the other day, wow was it hard. much much harder to take material off than euro style steel knives. i could tell right away. i dialed that one in on 16 degree bevel. i KNOW that bevel was established, because i had to grind a nick out, which took a LONG time on the coarest grit belt. like 30 plus passes on each side! i started cranking up the speed eventually because it wasn't going anywhere. that knife came to a nice edge, but it wasn't screaming sharp.
 
i called worksharp to try and get some info. i really don't feel the knives are getting as sharp as they should. they suggested i raise a burr with every belt, not just the x65. the instruction manual says to raise a burr on x65, then progress through the finer belts alternating passes, thereby not allowing a burr to the raised. after 10 or 15 passes at the finer belts, i can't feel any burr. i think it takes longer to sharper knives with this thing than a traditional stone. they say only use low speed, x65 doesn't take more than 5-10 passes on the first side to raise a burr, but the finer belts, what 20? 30? per side??? shit it'll take me half an hour to sharpen one knife. i might as well use a stone if i need to make THAT many passes. i'm going to call them again next week.
 
I have found that some knives that have questionable steel will take extra work to get them as sharp as other knives with good steel. Sometimes the cheap stuff just will not sharpen to a quality edge, and then become a time and material waste of time. I have a small sharpening business as a sideline, and have all types of blades coming to me, and some will readily sharpen, while other (Pakistani, some Chinese, etc.) will not give good results. I will bet that your knives with good known steel sharpen up quickly and easily, and hold and maintain a good edge. Just what I have observed, YMMV.

Blessings,

Omar
 
I have had the same experience as Omar. A while back, on a lark I bought a set of made in Pakistan pocket knives off the well known auction site. They actually had fairly nice looking scales and good snap. They cost next to nothing. I set about to sharpen them up on my WSKTS KO and for the life of me, I couldn't put any kind of decent edge on them. I finally gave up, and now have a complete set of mini paint scrapers. :o

Andrew
 
chado skins said:
i called worksharp to try and get some info. i really don't feel the knives are getting as sharp as they should. they suggested i raise a burr with every belt, not just the x65. the instruction manual says to raise a burr on x65, then progress through the finer belts alternating passes, thereby not allowing a burr to the raised. after 10 or 15 passes at the finer belts, i can't feel any burr.
Click to expand...

If you don't feel a burr, you either aren't hitting the apex, or you haven't figured out how to feel for finer burrs yet. I'm voting for: You aren't hitting the apex. I've had this same issue with the WSKO, primarily on the X4 belt. In my case, I think the problem is two fold: The stock belts are very flexible and will deflect with decent pressure. That, and I think I use too much pressure in general trying to get the edge ground in faster.

You can try one of two things:

1. Use less pressure from the very start with the coarsest belt until you form a burr.
2. After your coarsest belt, try raising the angle just a hair higher. If it's a matter of the belt deflecting more on the lower grits, this will allow the higher grit belts to actually touch the edge of the edge.

I've had to do #2 above numerous times with the stock belts, again, mostly with the X4 belt. Now that I have the stiff belt set, I haven't had to do that at all, and I've done a good number of knives. I should emphasize here that I DO get a burr with every belt on the WSKO and I get generally fantastic results with it.

Addressing Austin and a few others about steel quality and the ability of the WSKO to get good edges: I've now done around 115 blades with the WSKO and have only failed to make a "real edge" on perhaps 3 blades. Not counting the finely serrated blades that I was slowly converting to plain edges. On those very few blades, I could barely form a burr and couldn't get the edge refined. It was VERY strange because with every other blade, I got what I expected more or less.

Yes, blades with poor quality steel didn't take nearly as good, or consistent of an edge, but even average cheap knives shave hair and glide though phonebook paper with the edges I get on this awesome machine. :)

Addressing the point way up above about getting toothy edges with this machine: I have been experimenting with an edge that I do my last real grinding step with the stiff X100 belt, and then do a very small number of passes with the stiff X5 belt to remove the burr and micropolish the "teeth" at the edge. The resulting edge is a very interesting combination that can shave a little hair, clean slice phonebook paper, and seems to bite into things like tape on cardboard boxes much more aggressively than a more fine edge does. The edge holding seems to have increased dramatically as well.

Brian.
 
Agreed. And I should have clarified: in general, getting excellent edges on cheap knives is no problem with the KO. In fact, I haven't encountered a cheap Chinese kitchen knife yet which didn't take a terrific edge with the KO. That's why those little Pakistani pocket knives were such a puzzler.... :confused:

Andrew
 
In general Chinese knives take a good edge easily but it doesn't hold very long. Still quite usable. I have yet to see a Pakistani knife, tweezers, surgical instrument, file, jeweler's tool etc that performed at all. I don't even bother to sharpen Pakistani knives - it is a waste of grit. I have no idea what they do or what steels they use or how they temper, but it is uniformly AWFUL steel.

---
Ken
 
Thanks, Ken. Those little Pakistani folders were making me think I'd entered the Twilight Zone.

Oddly, another steel which has given me problems on the KO is at the other end of the quality scale: CPM 3V. On a couple of occasions I've had nice Bark Rivers in 3v come my way and I've only been able to manage a "working edge" on them with the KO. They weren't my knives so I didn't keep at it too long for fear of removing too much metal on someone else's knife, but I was disappointed as I can always get a beautiful edge on Barkies with A2. Made me wish I still had those nice linen + CBN belts you kindly loaned me a while back---I bet they would've been just the ticket for 3v.

Andrew
 
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