Uneven Bevels?
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- This topic has 9 replies, 4 voices, and was last updated 10/01/2013 at 2:10 am by
Leo Barr.
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09/29/2013 at 9:48 pm #15066
So, I’ve been using my Wicked Edge PPI for awhile now and I’m very happy with the results I can get with it. One issue I seem to have though are uneven bevels. This has happened on almost every knife I’ve sharpened, and it gets quite annoying at times to inspect an edge after sharpening and find that one bevel is quite larger than the other. I re-profiled my ZT 0551 to 17.5 degrees per side and say you have it clamped in the WE, the right bevel is larger than the left. This happens with my other knives, and it varies with being on the right or left bevel. I did a search of the WE Forum and read that this could be happening because most knives from the factory arrive with the edge offset. So, using my 0551 as an example, and with the right bevel being larger, the edge was offset towards the right?
One other thing I’d like to mention, and this has happened on a few knives, and It’s usually towards the heel of the blade, but It’s like the angle all of a sudden dipped down a degree and the bevel ends up looking even all the way down the bevel until it gets to where the bevel dipped down and It’s like a wave.
09/29/2013 at 11:29 pm #15067This is just from my own experience and thoughts on the matter. If I were to sharpen a knife with the exact angle that it was sharpened with both bevels even, then both bevels would remain even, but in reprofiling such can not be the case because you must take off more steel to create the burr on the opposite side.
In reprofiling a blade, my thoughts are that you can not keep going on one side and not have one bevel wider than the other. You must do both sides alternately until a burr is created on one side or the other or you must grind on the lesser bevel until it equals the opposite side. That would put the apex of the cutting edge close to dead center.
This is just my personal form of common sense. Tell me I’m wrong, but make me believe it.
09/30/2013 at 12:21 am #15070I would say there are two things to consider firstly that a lot of knives are done on a belt sander at the factory so they are set.by hand and are unlikely to have even bevels .
When sharpening with any method it is important to check that the bevels look equal on both sides the mk 1 eye ball is the preferred tool for this once you get them equal then keeping them so should be easier . I would also say that all you need is a tiny burr especially on the higher grits it is worth checking with a loupe with reasonable magnification . Lastly when you eventually get to do a ceramic blade there is no burr glass does not burr so you have to look with a loupe to see if the bevel has reached the edge .
So perhaps use a loupe more and the burr a little less since the burr indicates that you have gone through the edge .09/30/2013 at 2:00 am #15073So, I’ve been using my Wicked Edge PPI for awhile now and I’m very happy with the results I can get with it. One issue I seem to have though are uneven bevels. This has happened on almost every knife I’ve sharpened, and it gets quite annoying at times to inspect an edge after sharpening and find that one bevel is quite larger than the other. I re-profiled my ZT 0551 to 17.5 degrees per side and say you have it clamped in the WE, the right bevel is larger than the left. This happens with my other knives, and it varies with being on the right or left bevel. I did a search of the WE Forum and read that this could be happening because most knives from the factory arrive with the edge offset. So, using my 0551 as an example, and with the right bevel being larger, the edge was offset towards the right?
How are you measuring angles? I’m guessing with an angle gauge, but thought I’d check. Assuming that the angles are the same on both sides, and that the knife is correctly clamped (and there’s no issue with the clamp), then it’s probably the knife is off. But if it’s happening on “almost every knife”, I’d check the equipment also… in particular, make sure your clamp isn’t bent at the tip.
One other thing I’d like to mention, and this has happened on a few knives, and It’s usually towards the heel of the blade, but It’s like the angle all of a sudden dipped down a degree and the bevel ends up looking even all the way down the bevel until it gets to where the bevel dipped down and It’s like a wave.
Do you mean something like this?….
That’s often caused by the edge “flaring out” where it connects at the heel, which will slightly change how the stone contacts. It’s hard to see in the picture, but after this happened, I cut a little “sharpening choil” in the blade with a dremel.
Attachments:09/30/2013 at 2:12 am #15075This is just from my own experience and thoughts on the matter. If I were to sharpen a knife with the exact angle that it was sharpened with both bevels even, then both bevels would remain even, but in reprofiling such can not be the case because you must take off more steel to create the burr on the opposite side.
In reprofiling a blade, my thoughts are that you can not keep going on one side and not have one bevel wider than the other. You must do both sides alternately until a burr is created on one side or the other or you must grind on the lesser bevel until it equals the opposite side. That would put the apex of the cutting edge close to dead center.
This is just my personal form of common sense. Tell me I’m wrong, but make me believe it.
Ok….. 🙂 (if I understood you right)…
Assuming that the edge is centered to start, and you’re reprofiling to a lower angle, then even if you do one side at a time, in the end, it’ll still be centered. In my poorly drawn diagram…
… where the knife is being reprofiled from 20 deg. (the solid line) to 15 deg. (the dotted line), the stone (set at 15 deg.) will contact at the base of the bevel, and remove metal toward the edge. So when you reach the edge, and create a burr, it will still be in the center. Switch sides and repeat. 🙂
But, in reality, it’s good to work both sides a bit at a time, so that you don’t oversharpen one side, and push the edge off center, which can easily happen.
You’re right, if the bevels are off to begin with… then you have to work one side more to correct it.
Attachments:09/30/2013 at 3:34 am #15076So, I’ve been using my Wicked Edge PPI for awhile now and I’m very happy with the results I can get with it. One issue I seem to have though are uneven bevels. This has happened on almost every knife I’ve sharpened, and it gets quite annoying at times to inspect an edge after sharpening and find that one bevel is quite larger than the other. I re-profiled my ZT 0551 to 17.5 degrees per side and say you have it clamped in the WE, the right bevel is larger than the left. This happens with my other knives, and it varies with being on the right or left bevel. I did a search of the WE Forum and read that this could be happening because most knives from the factory arrive with the edge offset. So, using my 0551 as an example, and with the right bevel being larger, the edge was offset towards the right?
How are you measuring angles? I’m guessing with an angle gauge, but thought I’d check. Assuming that the angles are the same on both sides, and that the knife is correctly clamped (and there’s no issue with the clamp), then it’s probably the knife is off. But if it’s happening on “almost every knife”, I’d check the equipment also… in particular, make sure your clamp isn’t bent at the tip.
One other thing I’d like to mention, and this has happened on a few knives, and It’s usually towards the heel of the blade, but It’s like the angle all of a sudden dipped down a degree and the bevel ends up looking even all the way down the bevel until it gets to where the bevel dipped down and It’s like a wave.
Do you mean something like this?….
That’s often caused by the edge “flaring out” where it connects at the heel, which will slightly change how the stone contacts. It’s hard to see in the picture, but after this happened, I cut a little “sharpening choil” in the blade with a dremel.
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I’m using the angle gauge. I just checked the clamp and everything looks perfectly flat.That’s exactly what I’m talking about. Sometimes it’ll look like it does in the picture, or it’ll be one little spot.
09/30/2013 at 3:40 am #15077This is just from my own experience and thoughts on the matter. If I were to sharpen a knife with the exact angle that it was sharpened with both bevels even, then both bevels would remain even, but in reprofiling such can not be the case because you must take off more steel to create the burr on the opposite side.
In reprofiling a blade, my thoughts are that you can not keep going on one side and not have one bevel wider than the other. You must do both sides alternately until a burr is created on one side or the other or you must grind on the lesser bevel until it equals the opposite side. That would put the apex of the cutting edge close to dead center.
This is just my personal form of common sense. Tell me I’m wrong, but make me believe it.
I understand what you’re saying, but if both stones are set at 17*, why would one bevel end up larger than the other? Even if you’re removing more steel from one bevel than the other, wouldn’t sharpening on the opposite bevel even out with the other, being that both are set at the same angle?
09/30/2013 at 7:57 am #15079I understand what you’re saying, but if both stones are set at 17*, why would one bevel end up larger than the other? Even if you’re removing more steel from one bevel than the other, wouldn’t sharpening on the opposite bevel even out with the other, being that both are set at the same angle?
No, as you can plainly see by the knives you’re working.
Looking at the diagram CBWX34 has drawn, picture one side done, now draw a solid line over the dotted line to represent the new angle on the one side intersecting with the old angle. There you have a burr. If you just go and remove that burr, you have one bevel wider than the other. Continue on the opposite side until the bevels are even
10/01/2013 at 1:21 am #15089I understand what you’re saying, but if both stones are set at 17*, why would one bevel end up larger than the other? Even if you’re removing more steel from one bevel than the other, wouldn’t sharpening on the opposite bevel even out with the other, being that both are set at the same angle?
No, as you can plainly see by the knives you’re working.
Looking at the diagram CBWX34 has drawn, picture one side done, now draw a solid line over the dotted line to represent the new angle on the one side intersecting with the old angle. There you have a burr. If you just go and remove that burr, you have one bevel wider than the other. Continue on the opposite side until the bevels are even
Basically, I’m just not sharpening enough on one side to even the bevel out to the other side?
10/01/2013 at 2:10 am #15090I think that you are making an assumption that the thinning bevels are symmetrical it is more than likely that they are not what may be revealing apart from looking down the knife from the tip to the heel you may even be able to see if the knife is not totally symmetrical I think that you will find few are ; you may even be able to put the angle cube onto the thinning bevel on each side to verify this .
This is why I would suggest since in all probability the knife is slightly uneven that you possible alter the angle fractionally on the side where the bevel appears lower which is probable the broader side so decrease this angle so the bevel extends further up the knife then you should have the appearance of even bevels .
I would expect few knives are perfect in every sense the WE highlights this.
The only other course would be to make the thinning bevels symmetrical providing you can set a low enough angle or thin the broader side by convexing it slightly so the taper at the cutting bevel is equal perhaps you should try this on a cheap knife before you go ahead and try it on this knife or you redo the thinning bevels entirely to equal the knife but I think this is quite an advanced exercise that is if you can get low enough to correct the thinning bevel ; it may well be a considerable amount of work to achieve this
I think the least difficult solution is probable to lower the cutting bevel on the broader side so it looks even ; or you could just live with it . -
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