Course Grit Sharpening, Again

M

me2

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Oct 11, 2003
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Just thought I'd report that I reached the next step in my studies of coarse edges. I can get knives hair whittling sharp off the stock Spyderco white Sharpmaker triangles. With care, it can also be done with the grey triangles. I've also gotten a hair whittling edge (beard hair, not baby cheek hair) off a 220 grit waterstone. Last weekend I was able to get an armhair shaving edge off a file, and a hair whittling edge off a 1000 grit waterstone. The 1000x stone, and medium grit waterstones in general, have given me problems before. I think I have it whipped now. The file took 3 or 4 tries, but I finally got there on my brothers Camillus Marine Combat Knife. A file wont actually cut most of my other knives.

This is all an effort to simplify my sharpening by using fewer steps to get the same edge. Hair whittling used to take 5 steps, from 90x, 400x, Spyderco Medium, Spyderco Fine, and strop. Now I'm down to 2. 220 grit waterstone, then 1000 grit waterstone. The 90x and 400x above are what I think was the grit on my Norton Coarse/Fine combo stone. I sold it and moved to King waterstones. Not the best, but both grits for $20.
 
I think you're on to something. I think it would surprise some "knuts" how sharp you can get a blade off the coarser grits. I almost always leave my edges at around 800/1000. This edge works best for me as a "working edge" Expirementation can produce some new ideas and besides, it's always good to question if something can be done differently. Thanks for the info.
 
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On to something ! This is what noteworthy authors have been writing about for years ...
That evidence/findings are just not propounded here much . The glamour rest in sparkle and shine not real everyday usage and what wears well . SURE, you can get a coarse edge sharp !! Walk in any large meat market and you'll find a half dozen men capable of sharpening their knives to hair whittling sharp on a Norton India stone of 3-400 grit, quickly . So, to balance things here, I'll agree you don't have to have 6-8 stones or sharpening steps and have spent several hundred dollars on this equipment . One can end up with a sharp blade just like your stating in one or two steps . Now, if you want to or enjoy that undertaking and have the time or its just your deal . Then by all means go for it . We'll enjoy reading about that as well . DM
 
Congratulations! You have whipped the hardest part, trust me. All the rest is just window dressing. Once you have mastered the ability to get shaving sharp on a course stone, the rest just falls into place.
 
Hair whittling for a 220 stone is probably because of the teeth on the edge grabbing into the scales of the hair. 220 stone is about 60 microns and the average human hair is around 45-60, you would need a steel with the right grain structure and a very soft touch but the cutting action is only there because of the teeth. Once the teeth of a coarse grit edge wear off your left with a very blunt edge, the whole point of going finer is to lessen the size of the teeth until your left with nothing but a perfect apex of steel letting the wear characteristics of the steel determine its edge retention. Coarse edges have their place with some things but I like to think I'm always getting the most out of my steel.
 
What you say is correct but to arrive at the blunted edge takes a long time . Then there are some well known authors that would disagree with you on some of your points .
Say one arrives at a good true bevel using a 250 grit on Norton's crystalline stone with a lite touch . Then stops there using it as is . Are you saying this is not maximizing the steel showing it potential but that it must be taken to 5000 or 8000 grit polish and strop inorder to accomplish this ? DM
 
From all the things I have ever cut between testing and normal use yes, IMO a edge that has a higher grit finish always win's in edge retention. Though this is not to say that some steels don't perform better with a coarser grit edge, how fine or coarse the grain of the steel seems to determine a bit of this. D2 would be a good example, D2 will usually hold its edge better if left at around a 600 grit finish, but if you look at the finer grain structure CPM-D2 its edge last longer is finished around 0.5 microns.

With a fine grit edge you also remove less metal on touch-up's, I can touch up a blade for 6+ months at a time without the need to go lower than a 1200 grit stone. This saves on the life of the blade and it cuts a 100x better than say if I left it at 220 grit, Its quick and easy to just use one stone and it can provide you a "good enough" cutting edge, but for me it would be like switching out my standard razor sharp knife for a butter knife. I think knives are for cutting and saws are for sawing.;)
 
Congrats on the new achievements! I have been able to get hair whittling edges for a while now with my 1000 grit Shapton Glasstone. I can go from dull to hair whittling on that stone in under a minute using a microbevel. You have to use a light touch, and unlike say a Norton waterstones the Glasstones are very resistant to gouging, so if your waterstones isn't resistant to gouging and you use a bit too much pressure you could be in for a frustrating time trying to microbevel. For steels that aren't prone to chipping on ceramics I find the Spyderco benchstones great for applying microbevels, but with some ZDP and other very high RC steels I have had microchipping from the Spyderco ceramics. That is how I ended up using waterstones, though I do use DMT's in 120, 320, and 600 grit rather than waterstones for coarse sharpening. With good technique CPM M4 can whittle hair off of the 320 and 600 grit DMT's, but I usually polish M4 out to .05 microns. I've been trying S90V at 320 grit with a light stropping on leather loaded with 1 micron spray and it slices a really long time while easily popping hairs nicely, even shaving some above the skin a tad. I think the whole coarse/polished argument comes down to how are you going to use the blade. For pure slicing like skinning a game animal coarse wins every time for me, though I've had mirrored edges work fine as well. It just took a while until the mirrored edge dulled so it got some tooth to it for the knife to actually start skinning better. For pushcutting like whittling polished is the winner. If you modify your cutting style to match the edge then you will get maximum performane (like push cutting cardboard with a polished edge rather than slicing it). I love my polished show off edges, but there is certainly a place for a well formed coarse edge. By well formed I mean it should be at minimum shaving very smoothly, or better yet tree topping and splitting hairs like the 120 grit edge Tom Krein put on my ZDP 189 Mule. Whitlling hair at 1000 grit is a great medium grit edge, as you have excellent push cutting performance as well as pretty good slicing aggression. It will do pretty much any cutting chore you ask of it well, though it won't have optimum edge retention on say whittling or skinning game. Then again, just the fact that it can anything you ask of it well and it is sharp enough to show off to people by whittling hair makes it a pretty good EDC edge, as in EDC you never know what you might run into.

Mike
 
We're not worthy, me2! At least I'm not. Maybe everyone else is, but not me.

The maker of your waterstones suggests using the 220-400 grit range to form an edge and the 800-1,200 grit range to finish it.
 
A 100X better ! You don't say, I'm sure you tested that figure to make sure it was correct . Well, I guess we'll have to agree to disagree on this one . Probably just minor points of interest as I'm sure those knife writers don't know what their talking about anyway . DM
 
yep, all the data can Be found here.................;)



Some like the coarse edge but its just not for me. knowind how to get a knife sharp at coarse levels is important though.
 
Ive had mixed results useing the course stone only. Dont know if its different knives and steels, or my skills, or even a combo of both.
 
Oh dont misunderstand. I've preferred, and still do, polished edges for a long time. I've never subscribed to the reasoning that a fine polished, razor sharp edge is overly delicate and will loose that edge too quickly to make it worth the effort. This is just one of those "I wonder if I can do this" moments. I must say, I do like the 1000x edge on my Griptillian in 154CM for EDC use. Its also nice to know that redoing it wont take half an hour through 5 steps. The quickest and best compromise I've found lately was the Norton Coarse/Fine India followed by stropping. Worked great, and just back to the strop for touch up. When that stopped working, back to the Fine, and finally, redo the whole thing.

The 220 grit whittling edge made something that looked like a fuzz stick on coarse hair (beard). It would not do the things that knifenut shows on his vids. I'd completely agree with him on how it was able to make the cuts with the teeth. Sort of like if you try to cut something small enough, everything eventually ends up a serrated edge. Spyderco serrations vs. rope or 220x vs. hair. I kind of picture it like each particle of abbrasive makes and polishes its own scallop/trough, like using a checkering file. I know thats not really what it looks like, but 2 years of chemistry in high school wasnt really the way it worked either, but it helped to understand what was happening.

Oh yea, thanks Thom. Someone else here did the trick with the file, and I've heard of fishermen using just a file on their fillet knives with great results when cutting slimy fish innards.
 
I believe Wayne Goddard and Phil Wilson are both proponents on the Norton combo stone followed by stropping. I know Phil Wilson has said that edge will be seriously toothy and still shave nicely. Since Phil Wilson focuses on hunting knives his choice of coarse edges is not surprising, as pure slicing cuts on thick hide covered in thick fur is more easily handled by a good coarse edge than a very polished edge. Plus, the coarse SiC side of those Norton combo stones should cut any steel out there.

Mike
 
Lately with my SharpMaker I've bypassed the fine stones and gone with the medium followed by stropping. A lot of what I cut is in the kitchen and opening packages where the extra bit of tooth is preferrable. Next step is to pickup some green rouge for the strop, I've read good things about what that stuff does to aid polishing the edge.
 
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