Dual grit edges?

[phillyjudge]

As I continue to improve my technique to really nail an apex with matching symmetrical bevels, a new variable pops up.

I recently got served up a number of YouTubes where the video shows the benefits of having one side of the bevel coarse and the other fine…

I love the toothy feel of a 600 grit edge but also love the push cut ability of something finer… I have polished the bevels and microbeveled coarse, but is a  left/right dual grit the best of both worlds? Or snake oil?

[airscapes]

Try it and see if you like it!  I have no experience with it and if it was really effective wouldn’t it be something the manufactures would do all do?

This reminds me of my first class  in automotive school back in the 80s.  A fellow students asked about some “High Performance add on accessory” and how great  it must be  and the teacher replied, if it was that simple, don’t you thing the manufacture would have done this at the factory?    Not saying this is snake oil, but also  not seeing (in my mind) how it would really help on a knife with equal bevels.  The way I understand it it, the apex cuts and you want the sides to slide though  whatever you are cutting (meat for instance).  The sides of the bevel don’t cut anything that I am aware of.   So how do you make an Apex 2 different grits when it ends at a peak?   Normally to get the best of both worlds, you finish your bevels and then add a micro bevel at a slightly wider angle using a courser grit.

Only way to know is to sharpen your most frequently used (something you are very familiar with how it cuts) knife in the manner in which you want to test and see how it performs.

 

 

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000Robert, Brewbear

[Brewbear]

I agree with @airscapes, only the apex will do the cutting and finishing the shoulders at different grits is a gimmic at best. Microbevels are a different story all together. They provide a toothier edge while protecting the said edge if you are not using a super steel but prefer an acute sharpening angle. Case in point, one of my knives is VG10 and came with a sloppy 20* per side factory edge. I was still in my “experimenting” mode so I quickly reprofiled it to 12* per side yielding  a very sharp and slicey blade with the “added” benefit of rolling the edge about every time I used it. After numerous tries and going thru many pages on this forum I ended up doing a microbevel at 14* using the 1000 grit stones. The blade itself is fairly thin behind the edge and with the modified sharpening I have a very useful knife.

[000Robert]

I saw a thread about that on the BFC forum. I called it, “gobbledygook”. Sounds to me like it’s just someone trying to get their name out there. I do plan on testing different grits and micro-bevels when I get a Edge-on-up PT50A soon.

My mind tells me that the alternate grinds would only make a difference when you are cutting some medium where you would want the edge to grab one side more than the other side. But I can’t imagine any real benefit from it, except maybe for a chef. But I’m not a chef. My main focus for a blade is an edge that is sharp and strong for Utility/Survival/Fighting style knives.

But I do sharpen some kitchen knives for the girls. Imagine this: A righthanded person is slicing a tomato. If while looking down at the tomato cutting slices from the right to left, would the edge work better with a polished edge on the left side looking down at it, and a course edge on the right side looking down at it? Or vice versa? That might be interesting to explore.

I tend to favor toothy edges around 600 – 800 grit. But I will test them against micro-bevels.

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Brewbear

[Brewbear]

Interesting point @OOORobert, I’d be interested in your findings.

[000Robert]

Brewbear wrote:

Interesting point @OOORobert, I’d be interested in your findings.

I’ll post my findings here on the forum. I need to acquire some test knives first. But I don’t want to buy them from individuals and take the chance of the heat treat of the steel being damaged somehow. I’ll probably be looking into some in the next few weeks with different steels. It might take a few months to really get started if I have to pay full price for the knives. Hopefully, I can find some factory seconds at a cheaper price. But I think that it will be fun to do.

[phillyjudge]

Here is a screenshot from Cedric and Ada on YouTube

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Brewbear, Readheads

[Readheads]

That is a beautiful sketch of the concept. I am going to give it a try and see if my 250x USB scope can detect the results. I’m thinking that it won’t be enough magnification though. Of course I am in the market for a more powerful scope anyway but I digresss.

If the nano-serrations are actually real and effective then it may work well to improve the sustainability of my steak knives which are non-serrated (for the pleasure of slicing steak on a plate). Obviously my steak knives dull quickly due to plate contact but I do not mind truing them up with my ceramic rod. The nano-serrations may improve my time between true ups as well as the cutting action through the charred outside of my steak.

Also, I don’t think a manufacturer would do it on a non-serrated steak knife because to resharpen it you would need special equipment like a WEPS.

[Marc H]

I share “airscape’s” logic and sentiments:

airscapes wrote:

I have no experience with it and if it was really effective wouldn’t it be something the manufactures would all do?    But also not seeing (in my mind) how it would really help on a knife with equal bevels. The way I understand it, the apex cuts and you want the sides to slide though whatever you are cutting (meat for instance). The sides of the bevel don’t cut anything that I am aware of.  So how do you make an apex two different grits when it ends at a common peak? Normally to get the best of both worlds, you finish your bevels and then add a micro bevel at a slightly wider angle using a courser grit. Only way to know is to sharpen your most frequently used knife (something you are very familiar with how it cuts) in the manner in which you want to test and see how it performs.

Knives have been made and sharpened for a very long time.  If this method was helpful and advantageous, it wouldn’t be pretty much unknown and unpracticed.  Someone would have tried it intentionally a long time ago or recognized the improved cutting or slicing results if it was done inadvertently.  Then that sharpening method would have been adapted and put into regular practice.

I can’t even guess how many knife forums, sharpening forums, articles and blogs I’ve read throughout the years with never even a hint or peep about this method.  It’s sort of like trying to reinvent the wheel in the knife sharpening world.

I’d think unbalanced bevel coarseness would cause uneven drag on the knife edge from side to side that could possibly steer the knife’s track or direction as it’s passing through the substrate you’re cutting.  I believe a proper and well applied micro-bevel has all the advantages you’re hoping to achieve.  It’s easier to apply and maintain.  You can experiment with the micro-bevel’s efficiency using different combinations of grits and/or micro-bevel angle profiles all while looking for improved cutting, slicing and knife edge longevity or durability.

Marc
(MarcH's Rack-Its)

[phillyjudge]

Just food for thought guys, not advocating one way or the other.

[000Robert]

phillyjudge wrote:

Just food for thought guys, not advocating one way or the other.

The best thing to do is do it and see if you find any benefit from it. There’s nothing wrong with that at all. Let us know what you discover. Personally, I just think it’s a ploy for those guys to get some more ‘likes’ and ‘subscribers’. But I’ll bet that there have been many people that have explored it over the decades.

[JimR]

I think it’s an interesting concept and the diagram reminds me a little bit of the  Henckels Eversharp steak knives edge. Of course that’s a much larger pattern of peaks and valleys, it’s obviously formed with a shaped sharpening media, and only one side is sharpened with this pattern. I sort of wonder what would really happen if you sharpened with two very different grits on opposite sides of the bevel as I don’t see the result looking quite like the diagram of the apex suggests.

• This reply was modified 3 years, 9 months ago by JimR.

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[tcmeyer]

A long time ago, to help me understand what made for a really sharp knife, I studied shaving razor blades and scalpels.  I talked my dentist into given me a few of his old scalpels, which turned out to be junk, so I Googled it and found you can buy scalpels right off of Amazon, so I bought a bunch.

I had really been curious as to how scalpels can slice through wet, slimey, living tissue, because I knew from experience that this was really difficult.  What possible angle and level of polishing could make that possible? What I found was that the scalpel was ground to about 600 grit, but only one side was polished.  The 600 grit makes for a good toothy edge, while the polish eases the blade through toughest material – whether hide or gristle.  Surprisingly, the included angle is about 30 degrees.

Here’s a few photos:

Sorry ’bout the different sizes.  The images are the same number of pixels, so go figure.  Anyway, these are opposite sides of the same blade and you can clearly see the difference in polish.  I compared it to other images of 600 grit blades at the same focal distances and they look the same.  FWIW, this is a number 10 scalpel, the same one you hear TV doctors ask for in surgery.

[Readheads]

Very interesting on the scalpel. It serves to substantiate that their may be cut mediums and techniques that could benefit from it. My thoughts are all raw meats and maybe the steak knife edge for longevity purposes.

I have some cheap non-serrated steak knives and I will try it. Thinking of trying diamond films on one side and the super coarse 50 grit on the other. What do you think about the angles per side and which side to do first ?

• This reply was modified 3 years, 9 months ago by Readheads.

[tcmeyer]

Clay reported at one time that he had some success with 200 as the “tooth”-producing grit.  Probably used as an elk-gutting and skinning application.  I don’t recall the details, but I would think that 50 grit is too coarse and would accelerate the loss of steel.  I have a set of non-serrated Wuesthof steak knives and they are quite thin and hard.  I’d be very leery of any grits coarser than 400, fearing possible fracturing along the apex.

I’ve never tried this dual-grit, dual-sided approach but it sure seems interesting.  I have two kitchen knives I made last year which are nearly identical except for the handle configuration (one is full tang) and I might try the dual-grit method on one and try to detect a difference while cutting various food items.  I think a single stroke with 400 grit on one side would do the trick.

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