Recommendation? Stop at 120?

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MtnHawk1

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May 22, 2019
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I usually finish sharpening at around 325-400 grit but am wondering about the pros and cons of finishing at 120. It would be more convenient to stop here as I use 120 in the progression between the 60 grit Manticore and the higher grits.

My knives are for wilderness and kitchen use, as well as some folders and multi-tools. Most are carbon steel but some stainless. They are all working, utility knives so not worried about how they look, only about how they perform. I also like to minimize my sharpening time, but not to the point of sacrificing quality.

I don't want to get into too much detail, such as going into all the different types of blade metals. This is just a general question, wondering if there really is much real-world performance difference between 120 grit and 325-400 grit over a wide range of uses.

I know there are all kinds of threads and posts about coarse vs. smooth edges, etc., but I don't recall seeing much about the specific question I'm asking. If so, I'd appreciate links.

Thanks!
 
No difference in my opinion. Sharp is sharp. Wether it’s coarse or fine makes no real difference.
 
It should not be a problem getting the blade sharp, with light deburring strokes to finish, you can get a coarse edge sharp enough to pass many of the standrad sharpening tests including shaving arm hair and slicing receipt paper.

2 areas to observe:
* See how it performs in your typical cutting tasks vs your 325 edges. If it does what you need it to do, there's nothing wrong with using a coarse toothy edge.
* See how your edge retention holds up. If you find yourself having to sharpen more often AND you're removing more metal using a very coarse grit, you might decide it's not worth and go back to a higher grit.
 
I'd think, once the geometry is set (with a coarser stone, if necessary) and the favored edge finish applied, it'd be simple enough to maintain that edge solely with whichever stone was used to finish it. In other words, if you already liked the 325-400 finish, it shouldn't be necessary, each time, to go back through a full progression (60 > 120 > etc...) to maintain it.

I say the above, because I seldom need to go back to a very coarse stone to tune up an edge after the geometry is set, and instead I just take it back to my favored finishing stone (India Fine, in that same 320-400 ballpark) for the typical uses you describe, i.e., all-around utility & kitchen use with simple carbon and mainstream kitchen stainless steels. Once geometry is set the first time, maintenance becomes essentially a 1-stone process after that, save for any simple stropping or steeling I might otherwise do along the way.

If you truly like the 120 finish in itself, there's no reason not to maintain it that way if you want to. But if you're considering just stopping there to simplify the progression, it may be that the progression itself was already overly complicated for the steels & uses you describe. In fact, I'd see no reason to go as coarse as 120 or lower at all, unless some very heavy repair work or reprofiling needs to be done. But again, if you like how it performs at 120, then go for it.
 
I use #150 only for most of my sharpening with DMT EEF for edge refining/microbeveling.
It streamlines sharpening and works great for high carbide steels.

But I feel that finer finishes work better for simple carbon steels.
 
A 120 grit will work fine. You can get some decent sharp working edges with that grit level. Using a lite touch one should be able to produce a good utility edge. DM
 
Example of a 120 grit convex edge at ~30 degrees inclusive on a Cold Steel Magnum Kukri machete in 1055 carbon steel, done with a cheap Chinese diamond file.
Also used the same file to create a sharpened back edge, as this was a home defense present for a friend of mine.
Pics can be clicked 2 x for more detail.







 
Thank you all for your great advice and info! :thumbsup:

I don't often hear of anyone using 120 grit to finish with and didn't want to waste time trying something that knowledgeable people already know doesn't work. I appreciate the confirmation that it can.

Obsessed with Edges, I am a minimalist type and, when possible, always like to maximize my results with a minimum amount of time and effort (but not at the expense of quality). This is an especially useful guideline to follow when I'm in the wilderness, where energy conservation is important. I have followed your excellent advice above for a few months and do not see how I could do any better at achieving my goals regarding sharpening and maintaining knife edges. Thank you! :)

miso2 said:
I use #150 only for most of my sharpening with DMT EEF for edge refining/microbeveling.
Click to expand...

Doesn't finishing with the DMT EEF diminish or remove the 150 grit edge?
 
MtnHawk1 said:
Doesn't finishing with the DMT EEF diminish or remove the 150 grit edge?
Click to expand...

If you keep grinding with it, yes eventually.
But it will take a long time.

What I get is an edge like below.
Coarse_edge2019.jpg

Edge2020.jpg


You may be able to see a tiny microbevel produced by the EEF stone.
The teeth created by #150 are retained.
If I want little more smoothness, I would use Edge Pro diamond matrix stone at #250 or Congress Tools Moldmaster #240 instead of Venev #150.
 
I've finished with 100 micron belts on the WSKO... but it's been so long that I can't remember how I deburred those blades. The 100 micron (roughly 100 grit) edge performed WAY BETTER than a 400 to 600 grit edge made on the same equipment. It lasted a lot longer for me.

My go to sharpening routine these days is a Trizact A160 belt, which is approximately 180 grit. I stop on this belt after forming a burr, then deburr with very fine Scotchbrite (belt) and rough side bare leather (belt). The deburring is more time consuming than you might expect, requiring many passes. It's also finicky, as I sometimes round off the edge in the process (usually with the Scotchbrite belt). But when I get it right the edge from this is extremely grabby (toothy) and quite sharp. Scores of 150 - 180 BESS are about my average with this method.

Using a 120 grit stone will be different of course. The apparent grit will be much lower since you are not using a moving belt. So your edge will be even more toothy. Deburring will probably be challenging on such a coarse stone. The deburring method demonstrated by our forum member "bluntcut" seems to work very well on extremely coarse stones.


Watch and listen carefully. There is some really good information in this video.

On the other hand, if you use an EXTREMELY FINE stone to deburr, you might be able to produce the fabled "refined toothy edge". The goal of an edge like this is to retain all of the teeth and corresponding penetration power of a coarse edge. At the same time though, you polish those teeth so that they produce a more refined cutting action. All of the penetration of a toothy edge (the grab), yet some of the refinement of a polished edge.

I have yet to be able to produce these. I need to do some experiments with various belts and see what I can do. The rolled newspaper test that I show in some of my videos is a great way to measure "toothiness".

Brian.
 
Coarse edges (BUT CRISP) = more aggressive slicing, longer edge retention in slicing work, more prone towards the edge rolling when push-cutting resistant material

Polished edges = smoother, easier push cutting, longer edge retention in push-cutting work, very quickly lose slicing aggression when cutting any sort of materials that induce some degree of abrasive wear.
 
miso2, thank you very much for your info and great photos!

I've often wondered what a coarse knife edge with a high grit finish actually looks like and very much appreciate finally seeing it!

bgentry, thank you for your post and video, especially mentioning that coarse edges can be problematic to deburr (I see David Martin also mentions this). I didn't know that and it is something to consider before going too low, but the video should help with that.

You mentioned you have some videos. I went on youtube but couldn't find them. Could you please give me a link or tell me where they are?

maximus83, thanks for the great link!

I see Post 16 there has another link, so all this should make interesting and informative reading!
 
MtnHawk1 said:
Doesn't finishing with the DMT EEF diminish or remove the 150 grit edge?
Click to expand...

miso2 said:
If you keep grinding with it, yes eventually.
But it will take a long time.

What I get is an edge like below.
Coarse_edge2019.jpg

Edge2020.jpg


You may be able to see a tiny microbevel produced by the EEF stone.
The teeth created by #150 are retained.
If I want little more smoothness, I would use Edge Pro diamond matrix stone at #250 or Congress Tools Moldmaster #240 instead of Venev #150.
Click to expand...

This is how I go about it as well. Occasionally I'll just use a coarse stone And finish as best I can for deburring - when you get to a very large abrasive the bottom of each scratch trough is unreachable from the other side, so some amount of burr is almost always present unless using a very soft stone, which tends to reduce "keen-ness" along the peaks.

The microbevel strategy was one I came to a few years after tinkering with steeling coarse edges and seeing the results that produced - very refined edge along the top but with irregularities that catch materials more easily and help to increase longevity.
QACX0Ael.jpg


For me, this is where a fine diamond jointering stone, an 8k waterstone or a very fine diamond plate come in handy, since not all blade steels respond well to being steeled. Also, if you go too far with the steel, the edge is drawn out and ruined. Go too far with a microbevel and the edge is only a little more refined than you'd intended.

Lay in a coarse initial grind - I've gone as low as 80 grit. Then microbevel with your finest stone at a slightly higher angle - 2 degrees /side if using a guide, maybe a few more if freehand.

This "wipes" off the outermost deviations along the apex, leaving you with a less coarse edge overall, but one that has a refined apex + irregularities larger than the abrasive could have made on its own. The angle is (paradoxically?) thinner across the edge yet less acute at the same time. You can get a similar effect using a very hard strop, but will have more control using a stone. This can be touched up a number of times on the same finishing stone, a hard strop, or if the steel is less hardened the rim of a coffee cup etc and will continue to cut "rough".

You can see superficial similarities between the two edges, this one IIRC was done on a 220 Norton waterstone (which grinds a lot less refined than a vitreous 220) followed by an 8k. The more refined your last stone prior to the microbevel, the less coarse the finished edge will be.
EE7c2xel.jpg


I pretty much never polish the entire bevel anymore with the only exception being the backs of chisels/plane irons, and some convex edges. I only use a micro if I have a very fine finishing stone on hand, otherwise I just stick to a single bevel.
 
In my effort to remove the burr on a coarse edge I've gone a little finer. But that grit doesn't touch in the dips of the scallops. So, I would just straighten the burr and stabilize that. And not worry about the rest of the edge, allow it to remain coarse. This works as well. DM
 
David Martin said:
In my effort to remove the burr on a coarse edge I've gone a little finer. But that grit doesn't touch in the dips of the scallops. So, I would just straighten the burr and stabilize that. And not worry about the rest of the edge, allow it to remain coarse. This works as well. DM
Click to expand...

Is my belief it has a lot less effect than a burr edge coming off a finer stone as any of the low point burrs from a coarse stone are almost 100% certain to be from a single pass = almost as strong as the deburred edge.
 
HeavyHanded said:
For me, this is where a fine diamond jointering stone, an 8k waterstone or a very fine diamond plate come in handy, since not all blade steels respond well to being steeled. Also, if you go too far with the steel, the edge is drawn out and ruined. Go too far with a microbevel and the edge is only a little more refined than you'd intended.

Lay in a coarse initial grind - I've gone as low as 80 grit. Then microbevel with your finest stone at a slightly higher angle - 2 degrees /side if using a guide, maybe a few more if freehand.

This "wipes" off the outermost deviations along the apex, leaving you with a less coarse edge overall, but one that has a refined apex + irregularities larger than the abrasive could have made on its own. The angle is (paradoxically?) thinner across the edge yet less acute at the same time. You can get a similar effect using a very hard strop, but will have more control using a stone. This can be touched up a number of times on the same finishing stone, a hard strop, or if the steel is less hardened the rim of a coffee cup etc and will continue to cut "rough".
Click to expand...

So you are mostly going single-bevel as well these days, what is your preferred finish grit on an EDU knife, and a chef knife?

For the "fine diamond jointering stone, an 8k waterstone or a very fine diamond plate", have you found something you're currently satisfied with? I recall you said elsewhere you haven't been thrilled with the finish of the EF and EEF DMT plates.
 
maximus83 said:
So you are mostly going single-bevel as well these days, what is your preferred finish grit on an EDU knife, and a chef knife?

For the "fine diamond jointering stone, an 8k waterstone or a very fine diamond plate", have you found something you're currently satisfied with? I recall you said elsewhere you haven't been thrilled with the finish of the EF and EEF DMT plates.
Click to expand...


I micro just about everything with exception only for hatchets, machetes, convex/Scandi or if I'm away from my gear (just touched my EDC on a Norton econo stone at work today, single cutting bevel stropped on paper).

My favorites in order:
- Global tooling 10 micron diamond jointering stone - the company that makes these has had problems with their press lately, I was lucky to get a new one a few months ago and currently is not listed. They call it a 600 grit (?) but when I busted down a piece of it the abrasive particles were 10 micron or smaller. It polishes at about an 8k JIS due to the composition.

- Suehiro Rika G8 - I use this most often on all steels that are not high carbide/high VC.

- DMT EEF or Ultrasharp 3k for plates.

- coffeecup rim if improvising in the kitchen, technically is a steeling process but same principle, just have to be conservative.
 
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