Wider bevels?

[hawaiihunter]

So I decided to take my Green Cts-204p out of the box and reprofile it. Knives are meant to be used. Anyway, I reprofiled it on my Edgepro apex with chosera stones. I went up the grits and wow, it takes a long time to reprofile it, way longer then my Tenacious. But I noticed that I got a wider bevel on one side. I am wondering if this could be due to my holding of the knife. I could have been holding it wrong on one side so I got a lower angle and therefore made a wider bevel on one side. The bevel is noticeable and is like 3/4 of a Millimeter bigger on one side. Kind of :spyder: bugs me, hehe, but I was wondering if anyone could give me input. Thanks again guys, Hunter.

[Surfingringo]

Odd. Did you just overwork one side? Assuming your angles are the same you should be able to work the other side until they even out. I'll step back and let someone more knowledgable reply though since I'm not familiar with the edge pro.

[chuck_roxas45]

That often happens with the Edge Pro. What I do to avoid this is to watch very early on in the process and try to see which side will be wider. If I see this, I'll double(or even just stop working on the wide side) the number of strokes on the side with the narrower bevels until they look more or less equal. Then I do the same number of strokes on each side until I finish.

[Cliff Stamp]

The bevel is noticeable and is like 3/4 of a Millimeter bigger on one side.

It is most likely due to the fact that the primary grind is uneven. There are only two solutions :

a) plane down the primary grind

b) move the edge off center with the spine to compensate

To do the second one, just sharpen on the narrow side until the bevels are equal, it is a complete waste of steel of course and also makes the edge unbalanced - but it evens out the look.

If you plane the primary grind out it will be the optimal solution however unless you have power equipment you are looking at about a half an hour of solid grinding with a decent stone.

[chuck_roxas45]

More often than not, it just seems to be different stroking between sides than a grossly uncentered grind. You check by looking if the edge is centered in the tang, looking at it edge up, from the tip.

[razorsharp]

it will be that there is more sharpening done on 1 side than the other. Sharpen the small side of the bevel till it becomes even with the other side.

[MadRookie]

It is most likely due to the fact that the primary grind is uneven. There are only two solutions :

a) plane down the primary grind

b) move the edge off center with the spine to compensate

To do the second one, just sharpen on the narrow side until the bevels are equal, it is a complete waste of steel of course and also makes the edge unbalanced - but it evens out the look.

If you plane the primary grind out it will be the optimal solution however unless you have power equipment you are looking at about a half an hour of solid grinding with a decent stone.

Exactly that!

Of late I have seen this quite often with some of the latest productions from Spyderco.......QC???

:)

[hawaiihunter]

Please explain how I could do option a please.

[MadRookie]

@ hawaiihunter

To regrind the primary grind to true center could be a very complex process for those that do not have the tools & expertise - as the entire blade face from edge to spine needs to be reground (if the blade has a flat grind).

Also care should be taken with regards to the heat buildup while grinding so as not to destroy the heat treat on the blade, especially close to the edge where it is thinnest with quickest heat buildup.

Doing it by hand without power tools is a schlep and if it is the side carrying the Spydie logo, this will be abraded and gone......

I would recommend that if you want to correct this, to have someone do it that can.

If the knife is new, the other option is to send it back to Spyderco.

Frustrating to say the least, but seemingly becoming more frequent of late.....


:)

[Surfingringo]

Ahem, or you could just do what Chuck and razorsharp suggested and sharpen a little more on the narrower side. Deciding you need to completely regrind your knife because one bevel looks a little wider than the other is kind of like going and buying a new set of tires because you notice one of yours is a little low on air. Just my opinion.

P.S. There is also option C, which is just make it sharp and use it.

[FCM415]

204P PM2 kicked my butt when I reprofiled it. Was gonna go down to my standard 30 incl but I left it at around 34. Nexttime I stock up on supplies Im gonna get an Atoma plate for the EP to level the playing field

I had the same thing happen, wider on the other side. I just compensated till they were even. It was a pain though.

[gaj999]

When you sharpen it in the future, why not just take the majority of the steel off the side with the narrower bevel?

Gordon

[MadRookie]

No matter how you sharpen it, while the primary grind is out, you will always have a wide & narrow bevel respectively if you sharpen both sides to the same degrees.

Sharpening more on one side does not fix it - it just moves the edge off center.

:)

[senorsquare]

I've had a couple of knives that came to me brand new with an off center edge. Most notable was a Tuff where the plunge lines looked about 55-45 instead of 50-50. I guess someone had a bad day at the grinder on that one. I never felt like it compromised performance so I just let it be.

[senorsquare]

Ahem, or you could just do what Chuck and razorsharp suggested and sharpen a little more on the narrower side. Deciding you need to completely regrind your knife because one bevel looks a little wider than the other is kind of like going and buying a new set of tires because you notice one of yours is a little low on air. Just my opinion.

P.S. There is also option C, which is just make it sharp and use it.

I tend to go with option C

[Surfingringo]

No matter how you sharpen it, while the primary grind is out, you will always have a wide & narrow bevel respectively if you sharpen both sides to the same degrees.

Sharpening more on one side does not fix it - it just moves the edge off center.

:)

By how much you think? Quarter of a millimeter?

And that is assuming of course that the primary grind is actually off (which we have no evidence to indicate).

You and Cliff are both more knowledgable about this than I am and I'm certainly not saying you are wrong...just that there's no reason to overcomplicate it.

[yablanowitz]

That was my thought. How do you experts know without seeing the blade in question that the edge is indeed centered now? And for that matter, sharpening one side a little more to even out the sides is a complete waste of steel, but hogging off the entire primary grind isn't? Give me a break.

[Cliff Stamp]

By how much you think?

The maximum would be half the spine thickness, however it is unlikely going to be that much as the primary would not be that uneven as you would notice it immediately.

And that is assuming of course that the primary grind is actually off (which we have no evidence to indicate).

There are only two possible causes :

a) the edge angles are uneven in sharpening

b) the primary angles are uneven in the original grind

The width of the bevel will be proportional to the edge bevel angle (if the primary grind is even) and so to make one bevel twice as wide as the other requires one edge to be ground at 20 dps and the other at 10 dps. It is rare that someone would do that because it is such a dramatic difference, it is more likely than the other alternative is true. This is actually extremely common, here is a video showing this behavior in a very dramatic fashion :

[video=youtube;BbVwovbea3k]https://youtu.be/BbVwovbea3k[/video]

On one side the bevel is three times as wide as the other and it is not consistent along the length of the blade. It is just the nature of belt grinding.

--

In regards to doing it, it just takes a benchstone and you put the knife with the wide bevel side down on the stone and you scrub the knife on the stone until the edge bevel gets to the thickness you want. Lots of people do this as part of the standard technique for sharpening, Murray Carter does it that way for example.

[MadRookie]

That was my thought. How do you experts know without seeing the blade in question that the edge is indeed centered now? And for that matter, sharpening one side a little more to even out the sides is a complete waste of steel, but hogging off the entire primary grind isn't? Give me a break.

Dude, take your break & leave the primary grind as is & try to get even bevels.....

If you can achieve that miracle without off-centering the edge, I will eat you blade with no salt or pepper.

:cool: :p

[Cliff Stamp]

And for that matter, sharpening one side a little more to even out the sides is a complete waste of steel, but hogging off the entire primary grind isn't?

Yes.

Grinding one side until the edge is moved over and the bevel centers removes height from the blade and thus lowers the cutting lifetime. Grinding the side of the blade down has the opposite effect and actually will increase the cutting lifetime and thus isn't wasting steel.

It is also why adding a relief grind or in fact doing a complete regrind like Krein made popular isn't a waste of steel. Again they increase the cutting lifetime of the blade, not decrease it.

As noted, lots of people do this kind of work every time they sharpen to make sure that the edge doesn't thicken with repeated sharpening. Murray Carter for example promotes flattening the primary grind each time you sharpen.

As to how these things are known, it is a well kept secret that is known to only a select very few people. It is called physics.