Straightening an edge

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gilla409

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Dec 8, 2014
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https://www.instagram.com/p/BXkRCdGF3Q0/
So I got this beautiful custom modified Wharncliffe, but the straight edge has a low spot right in the center. I brought it to a local sharpener who greatly improved the bevel and made it scary sharp, but there's still that annoying low spot. It doesn't affect performance, but bugse nonetheless.

What would be the best way to fix this low spot and straighten the edge? Should I speak to the pro and tell him exactly what I want and let him do it with proper gear, or do it myself with my Lansky kit? It's 61HRC 3v steel, so I'm sure it'll take a lot of work and care going the DIY route, but with some guidance I think I can handle it.

Thanks in advance for any assistance.
 
3V even at 61 should be fairly easy to grind. Have at it with your Lansky. Turn to the pro if you are unsucessful. My issue is that the edge was already ground and that the low spot persisted. Could be that the blade itself was not straight to begin with.
 
It's physics sir.
Respectfully, you will focus on that low spot, and wind up cutting more steel away.

What I found that helps is a sharpie marker.
ID your "low spot", mark it, and stay the f away from it while sharpening.

If the spot is so low that it bothers you... imagine how you will feel removing enough surrounding steel to level it!

I'm a budding sharpener, and I have to level (no pun) with customers. I show them blades that have been "leveled", and virgins.
Generally speaking they live with what they have, rather than go for symmetrical, and loose steel.

Look at it this way... A horse shoe can be razor sharp all the way around. Does it not cut the same?
Good luck!
 
Zombie411 said:
Generally speaking they live with what they have...[or]...lose steel.
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I would live with it. I have a couple of blades with uneven grinds. They perform great. I reprofiled an edge earlier in the day. Shun VG-10. Uneven and possibly distracting to even the casual observer? You bet. Draw cuts newsprint at 12/15? Of course. Not all of my blades are left like this, but it does not bother me in the least as it will perform!

shun.vg-10.jpg
 
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adamlau said:
I would live with it. I have a couple of blades with uneven grinds. They perform great. I reprofile an edge earlier in the day. Shun VG-10. Uneven and possibly distracting to the casual observer? You bet? Draw cuts newsprint at 12/15? Of course. Not all of my blades are left like this, but it does not bother me in the least as it will perform!

View attachment 755877
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This brings up another important point.

That low spot may just be from softer steel in that area.
The Damascus in the above post is a PRIME example. You may file/grind away all day on the harder steel surrounding that spot, and STILL end up with a "wear point" in the blade.

Tough call... without seeing it first hand.
 
The grind looks pretty even, and the spot is about 1.5 inches long and maybe 1mm low, so don't think I'll be losing all that much material correcting it. That said, the edge on it is so hair splitting sharp and pretty that I think I should probably see the pro again and see what he thinks. I'd hate to mangle his beautiful edge trying to "fix" something that's not really broken... it's more of an OCD thing anyway. Luckily the guy lives about a mile away and works from home, so it shouldn't be a big deal. He's been sharpening blades for a long time, so I trust his judgement more than my own.

Once I get his opinion and/or correct the low spot, I'll start working on my own sharpening skills. I'd rather practice on something that's right to begin with than risk making it unusable for any length of time... this is a work knife first and foremost.

Thanks for the opinions and input, you've brought up several points I hadn't even thought of!
 
gilla409 said:
Once I get his opinion and/or correct the low spot, I'll start working on my own sharpening skills. I'd rather practice on something that's right to begin with than risk making it unusable for any length of time... this is a work knife first and foremost.
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One more point...
Buy some knife lots for 20 bucks, and work on the WORST edges first.
You/I/Anyone will never learn to make a tomato form a tomato.

Hone (LOL) your skills on the worst crap you can find.
It will teach you the most common mistakes, and how to correct them

Don't even worry about sharp. Make chipped blades straight, and re-file the choil if you have to.
Work on symmetry, and grace. Make a broken blade flow again.

Once you have a pile of re-born blades THEN start sharpening them. That exorcise alone will try your new found skills.
You won't want to mess up a blade you worked so hard to bring back no matter how cheap it was.

For your beater that you posted about? Fix that last. Make THAT your knife to be proud of.
Grind it w/ whatever stones, polish the burr off, and strop it like it's your first born. That F'r will be your pride, and joy.

Every knife after that will be a source of pride in skill.

I think I quoted this from a cereal box or Gandhi... forget which. Capt. Kangaroo? I forget... You get it!
 
adamlau said:
3V even at 61 should be fairly easy to grind. Have at it with your Lansky. Turn to the pro if you are unsucessful. My issue is that the edge was already ground and that the low spot persisted. Could be that the blade itself was not straight to begin with.
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The low spots I've seen in many of my own knives have been just that. It's a good possibility that it's a result of the primary grind. Sometimes it's a 'trough' made by too-heavy grinding on a belt during the blade's initial profiling; really bad examples will have a trough exactly the same width as the belt used to grind it (I have one like this). In attempting to remove it with further sharpening, you may end up chasing it all the way to the spine, and never fixing it. Not worth losing all that steel in pursuit of it.

As an alternative, I'd just use the knife and sharpen it as needed along the way. The earlier recommendation to mark the low spot with a Sharpie, and minimize too much grinding there, sounds like a good idea to me. Do what's needed to keep the apex crisp there, but try not to do too much beyond that, when touching it up. Bias the heavier work to the areas outside the low spot. Over time, if you're lucky, you might begin to notice the low spot diminishing a bit with repeated normal sharpenings.


David
 
gilla409 said:
https://www.instagram.com/p/BXkRCdGF3Q0/
So I got this beautiful custom modified Wharncliffe, but the straight edge has a low spot right in the center. I brought it to a local sharpener who greatly improved the bevel and made it scary sharp, but there's still that annoying low spot. It doesn't affect performance, but bugse nonetheless.

What would be the best way to fix this low spot and straighten the edge? Should I speak to the pro and tell him exactly what I want and let him do it with proper gear, or do it myself with my Lansky kit? It's 61HRC 3v steel, so I'm sure it'll take a lot of work and care going the DIY route, but with some guidance I think I can handle it.

Thanks in advance for any assistance.
Click to expand...

My experience... the majority of "low spots" are caused by improper sharpening somewhere along the way... that is magnified with subsequent sharpenings. You'll have a hard time correcting it with your Lansky... even if you know how.

Best way to fix it, is to put the blade straight down on a flat surface, establish a new flat profile, then sharpen in a new bevel and edge... (making sure you don't grind in a new low spot... the design of the blade is probably why you have one... for example if it widens out near the heel... that'll 'tip' the stone causing a low spot on the far side of the stone). I wouldn't fix it by trying to sharpen 'around' the low spot.

I would enjoy the edge now... since you like how sharp it is, then fix it when it needs to be sharpened.
 
Sorry for the delayed reply, been really busy on top of riding out a hurricane, lol.

This is the knife against an envelope so you can get a good look at the edge...
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Now I see it.

If you're willing to remove material, cbwx34 suggestion is what I'd take. Better be sure the stone is flat to have a real straight line.

It'll make the knife shorter, as basically you're moving the full edge back to be in line with the low spot.
 
I kinda figured, but I'm okay with that. It's quite a wide blade, and 1/4" thick, so there's plenty of meat left. Thank you for clearing that up for me!

I posted about this in another forum, and was mostly told that I should have sent it back to the maker, and the sharpener was at fault for the wobbly edge. I know without a doubt the sharpener did a great job, which happened to highlight a defect in the primary bevel. I just don't feel it necessary to send it back and wait who knows how long to get it back for something that can be fixed at home.
 
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If that's the "greatly improved" edge that the local sharpener did... I'd seek help elsewhere. (And I'd hate to see what it look like before it was "improved"). :eek:

There are several qualified individuals in this forum... who are up to the task. If interested, ask, and I'm sure one of them will help you out. :thumbsup:
 
He actually did do a fantastic job getting a hairsplitting edge on it. His sharpening skills and equipment definitely weren't the issue, it simply brought out the uneven grind. He even mentioned it as he returned the blade. He's already offered to work on it more, as that was just a 5 minute touch up that he did while I waited, but that idea was put on hold due to the hurricane.
 
You keep saying that, but if he had sharpened a straight edge properly (ie. On a flat stone or plate that allowed full edge contact) it would still be straight regardless of grind variation. Any irregularity would show itself as variation in edge bevel width.

~Chip
 
I have one that's not flat. It was made on a cnc also. I think it went out of flat when sharpening on the grinder. I'm not really going to worry about it. But yea it sucks makers don't make them completely flat sometimes.
 
I've noticed it is rare to get a perfect edge out of the box.
Mostly I see knives that are too thick at the heel and if I sharpen without grinding that even a recurve will appear.

Usually I will work the flaws out slowly, over a few sharpenings.

If they were all perfect though that would take some of the fun out of sharpening as a hobby.
 
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