Advantages and disadvantages of different sharpening techniques
- This topic has 63 replies, 9 voices, and was last updated 11/20/2018 at 12:14 pm by
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Redheads:
I just started a Forum Topic: Long Term Viability of a Knife Edge (Metallurgic Theories) Under Thoughts/Theories/Science Related to Sharpening which is in the Techniques and Sharpening Strategies Forum. I invite Redheads and others to continue this conversation with our Forum Members there. There are many knife sharpening issues we come across that are not WEPS related or WEPS solved. A variety of metallurgic issues are common. This is a good place to share these issues, concerns and theories.
Marc
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TC you bring up something I’ve been wondering about. Many knives I come across have those pesky little chips. As we remove them by taking off quite a bit of steel (relatively speaking) we start going into thicker parts of the blade which long term will require thinning of the blade. Is it possible to do thinning with the WEPS ?
Thinning a blade is a task best suited for a belt sander, where quite a bit of material can be removed in a short time. Where the blade has a grind that is more complex than an FFG kitchen knife, you’d need some special fixturing as well. I’d send you directly to Josh at Razor Edge Knives, knowing that he does outstanding work.
For the FFG kitchen knives, I have a 6″ – wide belt sander. I hold the blade flat against the belt, with my finger tips applying light pressure right behind the edge. When I feel heat starting to build, I remove the knife from the sander and dip it in a pitcher of water.
I did about fifteen very inexpensive 7.5″ Chicago Cutlery chefs’ knives like this which I gave as Christmas gifts. They come with an already-thin bevel shoulder at about 0.025″ and I thinned them down to between 0.010″ and 0.015″. Several recipients have said it was the best knife they’ve ever used. Of course, they’ve probably never even held a knife that thin, because only the best steels could stand up to regular use with an edge that thin. The steel in these knives is pretty good and they are a joy to use. I gave them with a promise of free sharpenings for life. Mine, not theirs.
TC you bring up something I’ve been wondering about. Many knives I come across have those pesky little chips. As we remove them by taking off quite a bit of steel (relatively speaking) we start going into thicker parts of the blade which long term will require thinning of the blade. Is it possible to do thinning with the WEPS ?
Unless the face grinds are relatively steep, as with a narrow-bladed folder, each sharpening probably removes less than 0.010″ at the apex, or about 1/4 of a millimeter. (This is about the average depth I see with typical chip damage.) Chips are supposed to be an unusual occurrence, compared to normal wear, so it should take quite a few sharpenings for the thickness of the blade at the bevel shoulders to be a factor. This would indicate that the knife is getting a lot of use and we must keep in mind that this is a consumable item. They don’t last forever unless you keep it in a display case.
Thinning a blade is a task best suited for a belt sander, where quite a bit of material can be removed in a short time. Where the blade has a grind that is more complex than an FFG kitchen knife, you’d need some special fixturing as well. I’d send you directly to Josh at Razor Edge Knives, knowing that he does outstanding work.
Tom, thanks for sharing this. It reminds me that my experience (or actually “lack of experience”) is very limited because I sharpen almost exclusively FFG Kitchen and Chef’s knives. I forget to consider the various grinds involved in EDC knives let alone all the other shaped knives like hunting knives, and fishing knives. Everyone of those is certainly more complex than FFG knives when it comes to a regrind.
Marc
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MarK76 by (thinning) the profile I meant thinning the knife so the width or thickness of the knife’s steel above/behind the shoulder is narrower. When you do this with the Wicked Edge you are really grinding or adding/profiling another bevel above/behind the knife’s cutting bevel. As you remove metal this extends this new bevel closer and closer to the knife’s edge. You can use the knife with the additional bevel and it is thinner than it was. Or eventually if you continue to remove metal, as these two bevel sides are extended towards the tip, it will become the new edge or apex of the knife.
By the way Mark76 the way the Forum mechanism adds quotes from the above post, to your forum response, it does sometimes place the wrong writer as responsible for the paraphrase quoted. In the case I refer to I am given credit for saying something Redheads wrote. I have noticed this in other instances too.
By my understanding, “the bevel” is the flat, slanted, narrowing sides of the knife ground into the knifes actual grind or shape. The bevels can be extended right to the apex where it becomes the edge. It also can be in incorporated with other bevels and not extend to edge. The point where the two opposite side bevels converge at the apex is the knife’s edge.
Marc
(MarcH's Rack-Its)1 user thanked author for this post.
I have thinned knives on several occasions using WEPS, admittedly and not proudly, with the best looking results. Here are some photos of one of my efforts done on a “Richmond Artifex Santoku in AEB-L. It’s a rather hard, tough steel. I wore out my WEPS Diamond Stones prematurely and scratched the knife badly. So much for the cosmetic character of the knife. In these photos you can see the two distinct bevels. As the profile of the knife changes along the knife’s length the shape and eveness of the thinning bevel also is affected. This can be seen by the shape of the bevel towards the heel of the knife.
The bad scratches on the knife’s sides towards the tip are from when I attempted to widen the thinning bevel “free hand” using an “Atoma” Diamond Plate Stone.
The bottom line, it was a good learning experience and the knife is thinner and performs better, with less effort. It ain’t no beauty but it is a beast! It works great on BBQ spare ribs.
I still consider getting a belt sander so I can attempt to do the job correctly, as Tom does.Marc
(MarcH's Rack-Its)Looks like a nice system. What in particular interests me is the design of the self centering knife holder clamp. It would be nice if Clay could apply that clamp design to the WEPS LAA. It probably would need some thinning out but I like that it’s self-centering.
Marc
(MarcH's Rack-Its)Mark, there seems to be a lot of confusion w/ terms when it comes to bevels/grinds and terminology. So after being in this business for several years I have come to realize that this confusion comes in part just from a lack of knowledge and partly from different terminology used on Japanese style knives vs. Western style knives. Here are the main terms that I feel are important (there are also variations of these but these are the main ones imho). The term grind and bevel can actually be used interchangeably, because when you grind something you are putting a bevel into it.
Primary Grind/Bevel
Secondary Grind/Bevel
Micro bevelSo for example, here is the typical Japanese definition for knife geometry. If you are into Japanese knives (like you are) then these are the terms you are probably most familiar with, terms that Murray Carter uses for knives he works on:
However, in this picture below this is the terminology we typically try to use (as knife makers and users) to describe knife geometry. I favor these terms personally because: 1. it makes more sense to me, as the primary grind is the main grind that makes a blade blank into an actual knife. 2. if you have a zero ground blade, using the first picture that would have to be called the ‘secondary edge/bevel’, which is can be confusing since in a zero ground blade there is only one bevel.
And when you get into micro bevels, they are “micro” as in you can either barely see it or not at all. this should be done at higher/more obtuse angles than the edge had been finished at with very light passes, less than 5-10 per side. This will add strength to the edge to resist lateral deformation (rolls, denting, and even chipping) and can also make touch ups much easier at the micro bevel angle (i.e. go from won’t cut to hair popping sharp in less than 45 seconds). But keep in mind that as you sharpen a micro bevel, it can turn into an additional bevel. I know you know a lot of this but hopefully it will help clear up confusion for others that read through in the coming months. 🙂
So, practically speaking. When people refer to the ‘edge’, or reprofiling/thinning the edge, they are referring to the secondary bevel – most are not referring to a full regrind of the primary bevel. The edge itself could have multiple bevels but I would still refer to this as the ‘secondary grind/bevel’. It’s not that either of these two sets of terms are better than the other, it’s mainly which preference you have and what types of knives you use – but sometimes it does need to be clarified.
Hope this helps 😀
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