Do you try to "correct" off-center edges during sharpening?

Bolster · #1

I've decided to sharpen and use my ZDP Stretch2. I am creating the back bevel (at 12 degrees per side, using a Lansky jig) and I've noticed that the original edge has been ground off center. In other words, a moderate amount of stonework has gotten me to the edge on one side, and the other side is requiring considerably more stonework before I reach the edge.

What I mean by "reaching the edge" is that, when grinding a steeper angle (looks like the Stretch was more or less about 15 degrees per side) you have to remove the shoulder of the existing bevel, before the stone actually reaches the edge.

Just to verify it wasn't my jig that was off, I took the knife out, flipped the Lansky around, and secured the knife going the opposite direction...same result, indicating it's the edge that's not centered.

So here's the question: would you...

(a) tend to follow the edge that the factory put on, meaning you'd work one side quite a bit more than the other, and then stop when you reached the existing edge (this would mean that you could see a different amount of reveal of bevel along the edge by comparing the two sides of the knife, one side having a larger reveal than the other). This method would remove the least amount of metal to obtain the edge. Or...

(b) would you try to re-center the edge into the middle of the blade. This would mean that you would continue grinding on one side (the side where the edge is reached with relatively little grinding) even after you'd reached the edge, so you're pushing the edge more into the center of the blade. This entails quite a bit more grinding, and it also means you're removing more metal than necessary to get an edge, but when you do get there, you're better centered.

Bolster · #2

Footnote moved...

Joshua J. · #3

Virtually every knife I own has an off center edge. I realized it while re-profiling one of my knives a few years ago. It bugs the heck out of me, especially on anything over $200.

Usually I do my best to fix it. If it's too bad I'll sharpen it like a chisel, except doing all my low grit sharpening on one side so that it eventually gets back to center.

Bolster · #4

Maybe Joshua and me are the only guys who have run into this issue??

I ended up doing your "chisel" style of sharpen on the Stretch 2. The steel is so valuable I couldn't cope with removing more than necessary...

I tried to even it out as much as I could, within reason, but when you look at the two sides, it's obvious one side has a larger bevel than the other.

Scottie3000 · #5

I dont think of it as removing more steel than necessary to get evenly angled bevels. You are not removing steel from the edge or making the knife blade smaller like an old worn out knife. You are simply removing the shoulder on one side more so you have an even bevel. Sometimes it just takes more work on one side to get your angle all the way to the edge. In the end, once you have done this once, the knife is set for the rest of its working life. Factories dont have time to get perfectly even 12 degree bevels, but you do. I'd say you are doing yourself and the knife an injustice be NOT evening it out.

LowTEC · #6

I found most of my knives comes with uneven grind. My blades MUST be re-ground to be perfectly center before I use them. The worst ones I have seen was D4 and E4 saber grind, more like 15+30 degree. I used to spend a lot of hours to regrind them back to 15/15, now my belt sander can get that done in 1/100 of the time than using stones. ZDP on the other hand can still take a couple hours even with belt sander if the grind is way off

unit · #7

Bolstermanic wrote:Maybe Joshua and me are the only guys who have run into this issue??

Not. I find some imperfection on every knife I have owned. Often the edge is among these imperfections. This is not to say that they are bad or even not very good...just not perfect.

I fix them and make them "mine".

They still are not "perfect" when I get done "fixing" them BTW. But they Are just more to my preference.

The Deacon · #8

I sharpen freehand, am not anal enough to measure edge angles that precisely, and probably create more lopsided ones than I receive.

freeman7 · #9

I "sharpen" my knives until they are sharp. I am certain that I do not have equal angles on both sides except by chance. I figure, if it is a user and it cuts to my satisfaction, it is fine. If it is a knife for the collection, I won't be sharpening it anyway.

ChapmanPreferred · #10

Lowtec,

What grit belts do you use for sharpening on your belt sander?

Thanks.

I also try to center the edge.

Doug

LowTEC · #11

Ranging from 80 micron down to 9 micron, then stropping on leather with .5 micron green

ChapmanPreferred · #12

Thanks LowTEC. Are there any more coarse grits available to you that might speed up your sharpening of ZDP?

Seanski · #13

Holy cow! When you guys start talking this kind of talk your way beyond me. :) I have
a Lansky system which I use to put bevels back on my blades then usually from there
I'm good for awhile with just stropping or a Sharpmaker. I don't think my eyes would
really pick up on a bevel difference out of a box from the factory and if I did see something from getting down and eyeballing carefully how the stone is actually hitting one shoulder then flipping and checking the other I would think that maybe my rod's were a bit bent or perhaps one is a bit off-clamp from the other causing the difference. All I really wanna do is getting it sharp.
The only problem I've ever had was originally with my Pacific Salt which I actually
couldn't sharpen properly out of the box on the Sharpmaker because of an un-even
bevel? Anyhow, the lansk took care of that minor issue.

LowTEC · #14

When you want every single one of your blade to be hair splitting sharp, you will need to start paying attention to the tiniest details to archive that. If you don't, your knife is not sharp :p jk

LowTEC · #15

ChapmanPreferred wrote:Thanks LowTEC. Are there any more coarse grits available to you that might speed up your sharpening of ZDP?

80 was the most coarse they make with that Aluminum Oxide (like sharpmaker?) & silicone carbide for knife sharpening

tac · #16

LowTEC wrote:When you want every single one of your blade to be hair splitting sharp, you will need to start paying attention to the tiniest details to archive that. If you don't, your knife is not sharp :p jk

Split hairs a lot, do you? :D

ChapmanPreferred · #17

Ah, I see. I do not know what the conversion is between 90 Micron and the grits I am familiar with from Lee Valley where the only Micron option is 15. I use the 80 and 120 grits from Lee Valley a lot for reprofiling and it works well for me.

LowTEC · #18

I think the Grit vs Micron is:

1200=9
X00 =15
500 =20
320 =40
180 =80

ChapmanPreferred · #19

Excellent LowTEC,
I will subscribe to this thread to keep track of that listing.
Thank you,
Doug

ChapmanPreferred · #20

LowTEC,

I'm going to try some of these ceramic belts in more coarse grits when I run low of my current stock.

http://www.supergrit.com/products/produ ... eramic.asp

Doug