Edge bite and stropping?

I

i_am_ninja

Joined
Nov 28, 2008
Messages
103
I use a lansky 5 stone guided sharpener and finish with several swipes on an extra fine DMT stone and several passes on my strop with green polishing compound. I can get hair splitting edges, but they don't bite at all.

When I run my 154cm and s90v blades across my nail I get minimal resistance but I can still shave the hairs off my arm. As cool as that is, I'd like an edge with more bite for my EDC folders (I hear they last longer too). Any advice on how to do that? I've tried going back to the extra fine stone after stropping but I dont think that's how it's done. :confused:
 
I don't think it is easy to have the best of both worlds. You could try to ease up on the strop, fewer strokes, less pressure, careful angle but it will ultimately take away the bite/finger stickyness. What I would suggest though is to try out 1-2 sheets of printer paper wrapped tightly around a coarse stone with or without compound. This way the risk of rounding is minimized but still refinement is possible. You could consider getting HeavyHanded's washboard for that exact purpos which will do an even better job. Alternatively consider a high quality compound on a nice, flat piece of Balsa wood (still use little pressure though, the wood is soft). The advantge of paper is obviously the ease of cleaning and little risk of contamination - through out and use a new sheet! Similiar with the Balsa, you just sand a new "layer" with sandpaper and you have a new strop.
 
Agreed. I'll give that a try, right now I'm using leather.

Man, having that hair popping sharpness is fun though! I remember back when I'd send my blades out for resharpening they'd come back with this really aggressive edge that could still push cut very well. I think it might have something to do with going from a coarser belt/stone straight to stropping. Might just be my imagination.
 
i_am_ninja said:
I use a lansky 5 stone guided sharpener and finish with several swipes on an extra fine DMT stone and several passes on my strop with green polishing compound. I can get hair splitting edges, but they don't bite at all.

When I run my 154cm and s90v blades across my nail I get minimal resistance but I can still shave the hairs off my arm. As cool as that is, I'd like an edge with more bite for my EDC folders (I hear they last longer too). Any advice on how to do that? I've tried going back to the extra fine stone after stropping but I dont think that's how it's done. :confused:
Click to expand...


If you're looking for 'bite' that you can feel in your fingertips, don't go any finer than something like DMT's 'Fine' grit (600 mesh/25µ); I'd even suggest finishing at anything down to ~320 or so (approximates DMT's 'Coarse' at 325-mesh/45µ). With your current Lansky 5-stone setup (standard hones?), chances are your 5th stone used for finishing is leaving something even finer than the DMT ExtraFine you followed it with. If the 4th & 5th stones in the Lansky kit are the '600' and '1000' ceramics (blue holder w/reddish stone, and yellow holder with white stone), you're definitely finer than the DMT EF with those. With ceramics, disregard the 'grit' numbers in trying to compare to the diamond, which are graded on an entirely different and much coarser scale, for a given 'grit' number.

You might re-establish the bevels with nothing beyond your 'Coarse' ('120') and 'Medium' ('280') hones in the Lansky kit; then strop with your green compound, and see if the 'bite' you're seeking comes around. For the tactile bite you're describing, I don't think you'll even want or need the DMT EF. Whatever stropping might be done should be minimal, as the bite you want is what's coming from the stones; stropping really should only involve cleaning up the burrs and any other weakened remnants left by the stones.

BTW, if you're using the standard (non-diamond) Lansky hones in working your S90V blade, I'd strongly recommend a full-diamond sequence with that one. The standard Lansky hones don't do very well with the heavy content of vanadium carbides in blades like those; I ruined two of these hones on an S30V blade (hones dished and glazed over), and that edge still wouldn't 'bite' either.

Whether the edge lasts any longer with more tactile bite, that's dependent on the steel and how the knife will be used. Softish steels especially won't hold onto their 'teeth' any better than they'll hold a polished edge, but you might find one finish is better for draw-cutting and slicing (toothy) and the other finish better for push-cutting, shaving or whittling (polished).


David
 
Last edited:
Per the above, you might try stopping at the 600 and work down if that isn't catchy enough. If you have a regular hardware store combination stone or similar, just wrap a sheet or two of newspaper, or a single sheet of copy paper and strop on plain paper wrapped around the stone. If burr free, this can make an edge with great bite and still have good pressure cutting.

For maintenance, refer back to Andy's response. Maintaining a toothy edge with a strop is generally going to mean a bit of work outside the box, a leather strop and green CrO is a poor choice for creating or maintaining a toothy edge. Especially true for steels with high carbide content like s90v or 154cm that don't respond generously to traditional stropping in general, beyond a very light final swipe (in my experience) no matter what abrasive is used. You would want to use a harder backing as suggested and a very hard mineral like diamond or CBN. Diamond lapping film can be used like a strop on these steels very successfully as well and is a good alternative to a lot of tinkering with backings and various compounds, just keep it in the teens for micron size, no smaller (the films also work well over a hard surface like the fine side of a combination stone). Or just restrict these steels to pure stone work and a minimum of stropping, even for maintenance.

On carbon or less wear resistant stainless there are many more options and much easier to tweak the edge effects for a variety of characteristics.

Martin
 
Most of what I use is lanskey. The purple coarse stone will put a great toothy bite on a blade. Just that stone, make sure you oil it. I get mine down to that real slick mirror edge also. But... when u polish one down like that it becomes so sharp it quits "grabbing" what your cutting. But incredible for slicing. Also I have issues with that super smooth polished edge collecting whatever I cut. I also have some "special" lanskey stones that are very hard to come by. And if you can use a lanskey like I can, I believe u deserve one of these stones. Email me and I'll hook u up.
 
What David said. :thumb up:

Long ago, I used to sharpen to hair whittling level, but I also found not bite left in the blade. Since I finally figured out that I don't push cut paper or shave for a living, I stopped it. I found out that for both my job in the machine shop and my hobbies of fishing and outdoor stuff, a more toothy courser edge worked out much better for me. I started to sharpen my knife on a old silica stone and leaving it at that. Not only did it give me a very sharp toothy edge that grabbed at cardboard, dirty greasy duct tape holding bundles of metal round stock, but worked much better at cleaning fish and stayed sharp noticeable longer.

Try sharpening your knife on a plain Norton economy stone and just leaving it at that. No or just a minimum of stropping. A very good edge for the real world.
 
My edges have plenty of bite up at 160,000 grit. Dropping through TP and Paper Towel like its not even there.

Ultimately this is a result of stropping on mystery compound with a softer backing.
 
Sadden said:
My edges have plenty of bite up at 160,000 grit. Dropping through TP and Paper Towel like its not even there.

Ultimately this is a result of stropping on mystery compound with a softer backing.
Click to expand...

Fair enough!
 
Is there really anything to be gained by an edge feeling sticky? Are these things perceived or measured?
 
Joe_Lane said:
Is there really anything to be gained by an edge feeling sticky? Are these things perceived or measured?
Click to expand...

I'd say, "it depends".

Just making the edge feel 'sticky' won't guarantee it performs better at a given task. Sometimes a 'sticky' edge is just a very coarse, jagged burr that'll fold over or strip off in use. Also, an edge can be made to feel 'sticky' on edge geometry that otherwise won't cut well at all (too obtuse). On the other hand, if you sharpen a blade to a certain 'stickiness' that also correlates to great cutting for a given task, then there's justification for seeking to repeat that same result each time you sharpen the edge. Well-exectuted sticky edges (i.e., crisply-apexed and free of burrs, at good cutting geometry) are great for things like tomato- or bread-slicing, rope-cutting or filleting fish. They're usually not so good at things like whittling or carving (sticky edges are 'sticky' and bind in the wood), or shaving (ouch) or fine push-cutting tasks.


David
 
I have no doubt that Sadden makes beautiful edges that do push cuts like demons. I've seen the pictures and I've seen limited video of them doing push tasks.

I'm far from an expert, but I use a blade a good bit. I mostly use it at work for opening cardboard boxes. In my experience, this is very hard on edges. VERY VERY hard. Most don't hold up for long at all and I need to touch them up a lot. Polished edges that *I* make don't last long for these tasks. The "best" steels I've tried for these tasks are ZDP-189 and S30V. Neither are near the top of the heap of steels, but most people label them both as "super steels".

In my experience these "super" steels last maybe 2 to 3 times as long as something like 440C and that's being generous. So I've experimented with levels of finish, going further and further down the chart to coarse edges for the S30V blade I've been carrying for the last year or so. I've found that the coarser the edge, the better it works and the longer it works.

It's actually kind of irritating, as I've spent such a long time trying to make polished push cut edges, only to find that for "real work" (that I do for money daily) they don't work worth a crap. Again, in my experience.

Two recipes have worked fairly well for me:

1. 100 Micron belt (on a WSKO) (roughly 100 grit) to form the edge, then just a very, very few passes on a 5 micron belt to clean up the edge. This edge lasts the longest I've tested so far, outlasting a polished edge by roughly a factor of 3.
2. Freehand edge from a Norton Crystolon Medium (roughly 180 grit) to form the edge, then cleaned up on a Spyderco Sharpmaker medium stone. Perhaps 8 passes per side. This lasts right in between a real polished edge and #1 above.

I love the feeling of clean slicing phonebook paper and having it whisper through the paper. I *want* that when I sharpen. But for what I use a workhorse blade for, it's not worth the time. I want it to clean slice the paper, but it will be loud and maybe hang a little bit. ....and it will bite the HELL out of tape on boxes and keep cutting for much longer.

Just my experience and opinions.

Brian.
 
U know, I've been doing the same. The rougher utility edge seems to last longer hu? And I find the 160,000 grit thing to be a bit impossible. I don't see how a knife could be sharper than what I can do, and I only get to 20k. And that's stupid scary dangerous sharp.
 
bgentry said:
I have no doubt that Sadden makes beautiful edges that do push cuts like demons. I've seen the pictures and I've seen limited video of them doing push tasks.

I'm far from an expert, but I use a blade a good bit. I mostly use it at work for opening cardboard boxes. In my experience, this is very hard on edges. VERY VERY hard. Most don't hold up for long at all and I need to touch them up a lot. Polished edges that *I* make don't last long for these tasks. The "best" steels I've tried for these tasks are ZDP-189 and S30V. Neither are near the top of the heap of steels, but most people label them both as "super steels".

In my experience these "super" steels last maybe 2 to 3 times as long as something like 440C and that's being generous. So I've experimented with levels of finish, going further and further down the chart to coarse edges for the S30V blade I've been carrying for the last year or so. I've found that the coarser the edge, the better it works and the longer it works.

It's actually kind of irritating, as I've spent such a long time trying to make polished push cut edges, only to find that for "real work" (that I do for money daily) they don't work worth a crap. Again, in my experience.

Two recipes have worked fairly well for me:

1. 100 Micron belt (on a WSKO) (roughly 100 grit) to form the edge, then just a very, very few passes on a 5 micron belt to clean up the edge. This edge lasts the longest I've tested so far, outlasting a polished edge by roughly a factor of 3.
2. Freehand edge from a Norton Crystolon Medium (roughly 180 grit) to form the edge, then cleaned up on a Spyderco Sharpmaker medium stone. Perhaps 8 passes per side. This lasts right in between a real polished edge and #1 above.

I love the feeling of clean slicing phonebook paper and having it whisper through the paper. I *want* that when I sharpen. But for what I use a workhorse blade for, it's not worth the time. I want it to clean slice the paper, but it will be loud and maybe hang a little bit. ....and it will bite the HELL out of tape on boxes and keep cutting for much longer.

Just my experience and opinions.

Brian.
Click to expand...

Much as the above, I find there's an intersection of steel type and intended task where the finish can make a big difference in longevity. At one point when experimenting for my hard use work knives, I was whipping up edges so coarse that they could not cut a sheet of paper with a press on a laminated desktop - the paper would stick to the edge and if turned over you could see where the tips of the edge formations had speared through the paper. These would still cut paper if presented at a very shallow shearing cut - the paper would actually get caught in a trough and cut as with a serration. Is a bit too coarse even for that job, but still was a good experiment. I settled on and used for a long time, 80 grit with no stropping but a slight microbevel - these edges lasted a long time compared to any I tried with a higher polish.


I am always tinkering to get that fine balance of push and draw on most edges for utility and this tends to shift around based on steel and geometry between 800 and 4k (JIS), otherwise the finish reflects the task - 600/800 grit toothy for my utility kitchen knives, 6k or better on my Chef's knives for chopping/dicing.
 
My best edges for cardboard all have 2000+ grit polished convexes in common, at relatively narrow geometry of 30° inclusive or slightly lower. The biggest 'bump' in cutting performance came from the convex itself, and additional gains by polishing it. The crisp shoulders of V-bevels I'd previously used in cardboard were noticeably prone to catching and binding in the cardboard, even with thinner blades at similar edge angle. Could actually see where the shoulders dug in, when looking closely at the blade lodged in the cardboard. I've liked the 2000+ finish out to the cutting edge itself, as coarser and toothy edges also tended to snag and tear the material, also clogging the edge with bits of cardboard stuck in the 'valleys' between teeth, once the apex started to lose some crispness. The finer-finished edge at good geometry just continued to slice away, minimizing the snags. I'm now convinced the narrower edge geometry and polished & convexed shoulders make the biggest difference. So far, I've given the above treatment to the following blades, all with essentially identical performance in cutting heavy cardboard:

Buck 112 (older '2-dot' version in 440C)
Case 6265 SAB Folding Hunter (skinner blade), in Case's older carbon steel (predecessor to their 'CV' steel, ca. 1965 or so)
Case 2138 Sod Buster (2009-vintage in Tru-Sharp/420HC stainless)
Buck 301 stockman (sheepfoot blade), in 420HC

I suspect more abrasion-resistant 'supersteels' like S30V would handle most any finish at the edge, with similar performance either way, so long as the edge geometry is good.


David
 
You must log in or register to reply here.
Back
Top