A balanced strop

[BluntCut MetalWorks]

I don't like strop but it can be easy to use or does it (see sticky above)? Talking about hold the angle, a single atomic mass pressure otherwise your edge will end up as rounded and or overly-convexed and or dulled and or wire. So I created sub-micron diamond stones and mostly edge-leading stroke to produce sharp & clean apex. OK so, it's worked well for me but not too useful for the rest of people :grumpy:

For 2 months, I've been looking/r&d for ONE/SINGLE/GRAIL strop with the following attributes:
* Sharp: clean shave (facial hairs), smooth diagonal slice newsprint, push-cut printer paper all directions, durable
* No rounding/convexing/dulling the edge up to 2.2lbs (1Kg) pressure - pardon my use the weight unit instead of SI (pascal)
* Sharpen/touchup/polish creates 99.9% free of burr/wire that affect performance
* Work for all carbon and most stainless steels (including high-alloy such as s90v)
* Durable edge
* Almost mirror finish
* Inexpensive : less than $10 total strop life cost (assembly & operate). WAG life worth - 10K uses on average (excluded knuts).
* Super easy to use

Here is my prototype (heheh fancy word for a piece of leather & some scrap wood)

Assembly: tacky glue leather nap/rough side to wood. Rub on unicorn dust compound - tba (to be announce or tease before announce )

Mora & Endura knives were stropped 16 minutes total (4 minutes per side, avg about 2 strokes per seconds) at about 1lbs of pressure. Fatigued arms cut a chunk out of my strop. Around 60% of the black swarf are from this 16 minutes of heavy stropping. Knives's edge angle pre & post stropped were unchanged (~30* & 25* included angles). Clean edge, clean shave facial stubbles, clean smooth diagonal slice newsprint.

Also I stropped s30v (bm 940) and a home made s90v knife. S30v came out great. S90v edge improved but there are carbides burr on edge, thus push cut ok but caught a bit when slice newsprint.

There are technical/physics rationales why this strop maybe/perhaps/crack-smoking possible. No point to go further, since there are plenty of sharpening experts around here boot me back to reality. Comments/kicks will be delightly receive...

 

[OHALLUM]

How did you cut a chunk out of your strop? Were you stropping leading edge? Did fatigue/maybe/perhaps/crack smoking cause you to forget which way you were stropping? Many questions here left unanswered. Of course you can take the fifth and not answer any of them. TBA later?

Blessings,

Omar

 

[BluntCut MetalWorks]

edge-trailing strokes but didn't lift high enough for the return motion, therefore dug forward. Just remember 2 strokes per second at 1lbs pressure, well my arm sure tighten up after a couple minutes of flipping back & forth edge-trailing /stropping motion.

edit: btw - that strop cost me ~ 30 cents.

 

[HeavyHanded]

1 pound of pressure too much - closer to 2-3 ounces, less than 6 in any event. If there's no rounding at 4+ pounds, maybe change of angle and hit closer to apex on convex profiles? I'm as cheap as they come, the best cheap strop is paper wrapped around one of your stones - two or three layers of paper for coarse edges, one for fine edges. Discard when loaded. Cheap unicorn compound - mud from waterstone works very well, have been using more and more silicon carbide mud from a combination stone (and just tested a Razor's Edge fine silicon carbide stone). A few drops of oil, a few minutes scrubbing on the stone with a piece of hacksaw blade or small file (assuming one didn't generate any mud while sharpening anything), wipe on copy paper and wrap that around the stone. Dry shave facial stubble - even the stubborn stuff around the corner of my mouth - crosscut paper towel and newspaper - still three finger sticky. Match the grade of 'compound' to the edge - mud from the coarse side of the stone = coarse edges etc.

Cheap, fast, recyclable, repeatable. Sit back and enjoy Scotch/fatigue/wonder if writing paper works better than copy paper/better than newspaper. Newspaper ink goes back into solution when exposed to mineral oil and smothers fine abrasives somewhat, all abrasives become too mobile on the surface for reliable results. Newspaper also more calendared, exposed to pressure with small amount of water during printing process - better for use as is and dry - otherwise copy/writing paper holds onto applied abrasives better especially in the presence of oil.

Paper over stone is hard enough to polish the back bevel of convex and flat ground edges using back and forth scrubbing, switch to trailing stroke for apex recondition/finishing. Strop cost difficult to estimate, less than 5 cents.

HH

 

[Chris "Anagarika"]

The strop I used is posted somewhere around this forum. Coffee box cardboard cut & put MAAS metal polish. Backed mostly on detergent box (those thick boxes) & strop away. All my knives (8Cr mostly) shave facial hair dry. In fact I always shave with my knives, primarily SRM 763.

 

[awestib]

Black and/or green (Enkay or ChromOxide paste from Chefsknivestogo) compound on thin leather strop, after I have removed the burr edge leading on stone as much as I can. Sharp enough for me, realitvely cheap. It's hard to get rid of the last bit of a burr from a let us say 1000 grit stone just on bare leather (belt for instance). You will most certainly end up with a too rounded edge, so I believe compound (or swurf from the stone) is needed.

 

[BluntCut MetalWorks]

HeavyHanded + Chris + Andy,

Your comments are appreciated. I've no doubt in my mind that your methods would work well for you and in most sharpener's hands. I used excessive pressure (as HH pointed out) to demonstrate that you still can get good result with poor technique. The strop is all blacken, shown the metal removal is fast. So it won't test the user patience. Also sufficient to see (in pics) that both blade have no distinct bevel, yes almost mirror convex but the cutting angle didn't changed/degraded. My wondering is whether this strop in the hand of non-knife people, would it still be effective?

Here is my material cost figures for people to build this strop:
$1 a nice piece of 1.5x16x3/8 wood
$1 1.5x12" cow/horse veg tan leather
$1.5 5oz of white 1200grit compound - enough for 10K uses, years of happy stropping unless the strop get cuts to pieces
$0.01 glue

Total is less than $4. My bare strop only cost me less than $0.30 for 1.5x9" of horse butt leather + 2 cents for compound. Even if some maker sells this strop+compound kit for $30, it's still worth while.

When the strop is blacken & slippery, scrape it down on concrete or use knife spine.

This strop is effective for edge off any stone up to 6K (plus dmt EE). For face shave, I strop the edge on bare leather at elevated angle to glide along the skin better, lessen chances of lopping thin layer of skin.

 

[My Young Apprentice]

How did you cut a chunk out of your strop? Were you stropping leading edge? Did fatigue/maybe/perhaps/crack smoking cause you to forget which way you were stropping? Many questions here left unanswered. Of course you can take the fifth and not answer any of them. TBA later?

Blessings,

Omar

^This question is pure awesomeness, and to be frank my concerns were the same xP

Sounds like you're overthinking it a bit though Bluntcut.
I'm sure you can get great results off of newspaper and a simple leather strop without going into pounds per square inch and whatnot. Next you'll be racking your brain over the tensile strength of the leather, the distance between each crease, the sub-atomic particle geometry of the stropping compound, and the amount of gamma rays that are touching your blade as it's getting stropped

 

[BluntCut MetalWorks]

Sounds like you're overthinking it a bit though Bluntcut.

You think

I'm sure you can get great results off of newspaper and a simple leather strop without going into pounds per square inch and whatnot. Next you'll be racking your brain over the tensile strength of the leather, the distance between each crease, the sub-atomic particle geometry of the stropping compound, and the amount of gamma rays that are touching your blade as it's getting stropped

I seek sharpening skills and knowledges at the same time share them to non-knife people, so just maybe more people can enjoy super sharp knives without required a science Ph.D and an artist highly dexterious hands. I don't worry about gamma rays nor drool on the blade but I do keep an eye out for electrostatic skin deep quantum magnetic eddies/vortexes

I had tried strop on many type of abrasives & backing including newspaper. Newspaper stropping abrades too slow for me and it didn't worked well for many type of stainless steel blades, plus not convenient (maybe safety too), plus backing complication (HeavyHanded's use rough stone backing is very effective).

 

[awestib]

I really like your approach bluntcut (and I just noticed that I lost my Gold Member status ...?). I love the idea of simple and "cheap" yet very effective sharpening method that can be done anywhere. One stone and a belt is what I have been pursuing, preferrable without need for oil or water (very unpractical in subzero conditions!!). I truly believe what HH and you have also supported, that removing the burr is the one and only crucial thing to get a sharp knife after an apex has properly been created.

Sooo, bluntcut, why are you not rounding the apex with your strop despite the pressure? Is the leather very thin and hard? I am not clear about this!

 

[BluntCut MetalWorks]

I really like your approach bluntcut (and I just noticed that I lost my Gold Member status ...?). I love the idea of simple and "cheap" yet very effective sharpening method that can be done anywhere. One stone and a belt is what I have been pursuing, preferrable without need for oil or water (very unpractical in subzero conditions!!). I truly believe what HH and you have also supported, that removing the burr is the one and only crucial thing to get a sharp knife after an apex has properly been created.

Thanks Andy!

Sooo, bluntcut, why are you not rounding the apex with your strop despite the pressure? Is the leather very thin and hard? I am not clear about this!

It's about the abrasive type & size (presumably 12-15micron AlOx). Right about 12 microns where rounding occurs and get worse as particle size get smaller. For diamond & SiC ~15micron rounding begun. Nappy leather help but once swarf cake-up, now it's mostly swarf+wax+abrasive surface, thus particle type & size are the key. Lol - I tried 6 micron diamond on my endura, wow it double my bevel angle in a few minutes. While 15micron diamond didn't round but the edge is more dirty (some burr + section of wire) than white compound.

I bought a 3lbs bar of white compound for $15 and 30cents per foot of 1.5" wid horse leather (yeah, I've around 54 feet <= save shipping heheh).

I am contemplating to make a video and hand-wave some physics about it. Hopefully some body replicate this setup to reject or confirm, otherwise it's just another useless r&d crap of mine

 

[Obsessed with Edges]

I have no earthly idea if there's any such thing as a single best strop. The only consistencies I can find, in my own evolution, is that I'm gradually moving away from 'soft' strops on hard backing, and relying more on very firm surfaces. I have an old, cheap 'paddle' sharpener of red cedar, which originally had a cheap Arkansas stone on one side, and a short length of stropping leather on the other. A little while back, I managed to separate the Arkansas stone from the paddle, and then sanded away the leftover glue/epoxy that was holding it there. The sanding did a very nice job in smoothing out the cedar, and I ended up applying some 1µ diamond paste directly onto the wood. This has actually worked very well for stropping more wear-resistant steels, and polishes bevels pretty well also. On less wear-resistant steels like 1095 and 420HC, I'm finding that my favorite strop is a leather belt, with green compound applied to the inner face of the leather. I use this one as a 'hanging strop' (barber style), and it's the best I've tried for these steels. Using it like a hanging strop, with some tension applied to keep it fairly taut, seems to minimize the rounding/blunting of the edge that I'd otherwise see on a leather-on-hard-backed strop on a bench.

Don't know yet, if other compounds might work better for me. But, I seem to get an awful lot done between the 1µ diamond, the green compound and on bare leather. I've tinkered with many others, but always come back to these ones.

Yesterday, I was fiddling with some 5µ and 0.3µ alumox 'honing film' from 3M (Pinnacle-branded packaging, purchased at a Woodcraft store). Used the strip of film laid flat on glass, held in place with some binder clips, and these are looking encouraging for use as 'strops'. Touched up edges on multiple knives, in 1095 (Schrade Old Timer), VG-10 (A.G. Russell 'Folding Cook's Knife'), D2 (Queen stockman), S30V and ZDP-189 (both Kershaw Leeks), and they all responded well to it. I'm actually VERY surprised at how easily this stuff handled the S30V and the ZDP-189. Also have some 15µ in the same package, but haven't tried it yet. This film is durable too; I've been cleaning it up with a Windex-moistened rag after each blade, and that takes a lot of the swarf off of it.


David

 

[BluntCut MetalWorks]

I have no earthly idea if there's any such thing as a single best strop. The only consistencies I can find, in my own evolution, is that I'm gradually moving away from 'soft' strops on hard backing, and relying more on very firm surfaces. I have an old, cheap 'paddle' sharpener of red cedar, which originally had a cheap Arkansas stone on one side, and a short length of stropping leather on the other. A little while back, I managed to separate the Arkansas stone from the paddle, and then sanded away the leftover glue/epoxy that was holding it there. The sanding did a very nice job in smoothing out the cedar, and I ended up applying some 1µ diamond paste directly onto the wood. This has actually worked very well for stropping more wear-resistant steels, and polishes bevels pretty well also. On less wear-resistant steels like 1095 and 420HC, I'm finding that my favorite strop is a leather belt, with green compound applied to the inner face of the leather. I use this one as a 'hanging strop' (barber style), and it's the best I've tried for these steels. Using it like a hanging strop, with some tension applied to keep it fairly taut, seems to minimize the rounding/blunting of the edge that I'd otherwise see on a leather-on-hard-backed strop on a bench.

Don't know yet, if other compounds might work better for me. But, I seem to get an awful lot done between the 1µ diamond, the green compound and on bare leather. I've tinkered with many others, but always come back to these ones.

Yesterday, I was fiddling with some 5µ and 0.3µ alumox 'honing film' from 3M (Pinnacle-branded packaging, purchased at a Woodcraft store). Used the strip of film laid flat on glass, held in place with some binder clips, and these are looking encouraging for use as 'strops'. Touched up edges on multiple knives, in 1095 (Schrade Old Timer), VG-10 (A.G. Russell 'Folding Cook's Knife'), D2 (Queen stockman), S30V and ZDP-189 (both Kershaw Leeks), and they all responded well to it. I'm actually VERY surprised at how easily this stuff handled the S30V and the ZDP-189. Also have some 15µ in the same package, but haven't tried it yet. This film is durable too; I've been cleaning it up with a Windex-moistened rag after each blade, and that takes a lot of the swarf off of it.


David

Hi David,

I was and still am I guess in the same path as you - use harder backing, except I rely on edge-leading for pure bevel & clean edge. Always, there will be compromises if one goes for a single strop solution. In my garage, I've more than 30 strops and a bunch of home made stones loaded with various compounds. There are abrasive states: fixed, partially embeded and loosely/tumbly which interact differently reflect in the different outcome. Hone-film has fixed abrasive so abrasion will be similar to a plate if it's on hard backing, like glass.

I found that reasonably hard abrasive at 12um or bigger can abrade most common to exotic steels. For smaller (than 12um) abrasive particles, it's important to choose the right abrasive type for the target steels.

It's not you or I that can't sharpen knives using various abrasives, as I ascertain you can sharpen a s30v knife using only a 1095 blade (yup, just 2 knives). Most people out there don't and won't have such basic sharpening skills. OK, you've done super job educating & helping countless people on the forum and probably people around you. Somehow, I still optimistic that we (knives people) can come up with some devices+techniques that affordable & easy for non-knive people to use to open those frozen micro-wave food packages - hmm maybe not that optimistic

 

[Chris "Anagarika"]

Thank you for your kind words. I think there should be a simple tools NKP can use.

However, if not all Knife People can do what is shown here, what is the chance NKP will have the interest (not to mention the patience to learn) and the skill to do that?

 

[Obsessed with Edges]

(...) Somehow, I still optimistic that we (knives people) can come up with some devices+techniques that affordable & easy for non-knive people to use to open those frozen micro-wave food packages - hmm maybe not that optimistic

Actually, this is why I feel driven to keep trying different things out, whether they're 'simple' materials or otherwise. One thing I've really appreciated in doing so, is the 'education' afforded in how different steels behave with different abrasives and methods. As you mentioned, the backing/substrate onto which the abrasive is applied makes a big (sometimes HUGE) difference. Seemingly 'soft' abrasives on one backing suddenly become much more aggressive on another. This can be seen in the swarf removed using only one compound, on two different substrates, like leather vs. balsa/other wood. Balsa blackens up a LOT faster with swarf, which testifies to the difference in aggressiveness afforded by the stronger 'foothold' for the abrasive, given by the wood.

If I were to recommend, today, just one 'best' and simple method, I'd probably go with silicon carbide wet/dry sandpaper. The finer grits at 1000+ have occasionally served as strops in my uses, especially when stropping on bare leather, or other surface without compound, isn't quite getting the job done. Sometimes it's a little less aggressive than hoped for, on very wear-resistant steels like S30V but, even then, it's still usually good enough to get by. And at the other end of the steel spectrum, it's a breeze with steels like basic carbon (1095) and simpler stainless (420HC, 440A/C, etc.). I think the sandpaper covers a wider spectrum of usefulness than anything else I've tried so far. And it's ready-made for laying atop any chosen backing, from very firm or hard, like glass or hardwood, to something a little more forgiving, like leather or stacked paper.


David

 

[awestib]

I totally agree to David, Sandpaper is an awesome solution for virtually everything and so versatile (hard flat backing, leather backing etc.). Everyone who had the opportunity to compare sandpaper even to diamond stones to repair a scandi grind, even just O1, knows how well it works. Stropping scandis flat on sandpaper with thick leather backing get's completely rid of the "weak" edge issue of a scandis with no noticeable loss of cutting ability, and it looks great (scandivex).

The only thing I don't like is that you have to change it regularly, you need a system in place to keep it flat/attached to the backing etc. So not so convenient for a longer outdoor stay.

Now, I may have found the perfect solution, at least eventually. DMT now offers this:

http://www.dmtsharp.com/sharpeners/specialty/flexi-sharp-sheets/

Unfortunately the only come in a too small size (biggest 2x3 inches) but maybe one day in 8x2 inches and then we have the durability of a diamond stone and the flexibility of sandpaper. What do you guys think?

 

[BluntCut MetalWorks]

I just stropped the Mora (carbon) on 1K w&d SiC, dmt E, dmt EE and 1K waterstone. SiC w&d is messy and loaded up too fast. Even with super light pressure (less than the weight of the blade), the blade endded up with a wire-edge. Therefore won't shave or slice newsprint well until I fold the burr & edge-lead to remove the wire, after that this fairly toothy edge will shave & slice newsprint. Fixed-abrasive requires high precision controlling angle+pressure+curvature+etc.. People with insufficient sharpening skills more likely to butter-edge their knives than sharpen them.

I guess a video about this grail-strop is warranted. It would worth exactly 1000 words 'Incoming, takes cover!' soon.

 

[HeavyHanded]

I just stropped the Mora (carbon) on 1K w&d SiC, dmt E, dmt EE and 1K waterstone. SiC w&d is messy and loaded up too fast. Even with super light pressure (less than the weight of the blade), the blade endded up with a wire-edge. Therefore won't shave or slice newsprint well until I fold the burr & edge-lead to remove the wire, after that this fairly toothy edge will shave & slice newsprint. Fixed-abrasive requires high precision controlling angle+pressure+curvature+etc.. People with insufficient sharpening skills more likely to butter-edge their knives than sharpen them.

I guess a video about this grail-strop is warranted. It would worth exactly 1000 words 'Incoming, takes cover!' soon.

I stopped using W&D sandpaper after too many instances of weak edges and stubborn burrs - too much post paper finishing work for me. Also figured out how to convex on a stone, so between the paper loading up and having constantly changing characteristics as it ages, decided it wasn't working well enough to continue (for me). Many of the issues could be alleviated by going to very high grit values, but at moderate (1000k or less) very few of my W&D edges survived a light, steep angle backdrag on the edge of a workbench, while nearly 100% of my JWS and benchstone edges handled this test fine. I came to think of W&D as something not quite a strop and not quite a stone, and not lapping either.
HH

 

[OHALLUM]

As posted by HH : "I came to think of W&D as something not quite a strop and not quite a stone, and not lapping either."

I have tried to use W&D for everything from a substitute stone, to a strop, and had little success with it. Whether by my procedure and lack of knowledge, or what ever, it just did not perform as I wanted it to. Lots of folks on here bragged about their use and success they had with it and it sounded like a good and cheap way to sharpen a knife. Well, as my grandfather use to say, "I'm calling calf rope". It just don't work for me.

But all was not lost, as I took what I had left and cleaned up some old slip joints with it. Removed some rust and polished the blades up real nice. I do admire people that can use it with success, but it evades me. Which is OK as I still have other things to fall back on.

Blessings,

Omar

 

[awestib]

Yes, I must agree that the loading up and the constant changing of the grit is an issue. I did not know about the actual edge quality after w&d sandpaper since I always stropped on black compound and thin leather after. Most work on sandpaper was repairing chipped scandis and besides changing the sheets all the time, it worked well. I have since changed my approach to scandi sharpening/repairing too and use jws and use the same motion as I use on double bevel edges. This works on diamond stones (I used the dotted ones) well too and no need for water or oil which makes it convenient for the outdoors.