Occasionally I sharpen knives for my relative restaurants. No fancy jknives involved.

In addition to Tom's points. Bring along a good loupe to inspect their knives & cutting boards. Looking at cuttingboard types + chop/slice/scrape marks + length/depth would reveal quite abit about their knife usage pattern. Your portfolio/sample knives: 1 crazy thin& sharp (don't leave this one there), 2 durable sharp. I made newb mistake with too thin & sharp, quickly rendered knives worthless dull (from rolled). If jknives involves, how's your freehand with bench waterstones & jnat?

Get cheap 1x30 AluminumOxide sanding belt resin cloth back, 40 thru 2K grit. Want ceramic 40-120 grit, get norton blaze belt. Cut & resin/expoxy, then heavy grinding away. Ok to wet grind too. These strips are very durable and will last a long while (many reprofile).

Remember to clean loose low grit/particles to minimize unwanted scratches.

7* inclusive is my lowest freehand angle on my 24cm v2(steel 64rc) gyuto. Yes was chippy and had a crazy time removing less than 2um tall wire-edge. Ok, that was a little bit passed V2's steel limit. I micro-bevel around 18* and with subsequence touchups it's slowly becoming a regular bevel. It would be super cool if WE supports this kind of acute angle sharpening or perhaps too crazy nor practical any way

A knife with super sharp + sub 20* inclusive angle + thin-behind-the-edge will easily pass this tomato test. This can be easily verify/reproduce by testing with a feather-brand double-edge (DE) razor. Note: DE edge is highly polished.

Tomato in Kono video is fairly firm. Tomato in Miz video is crunchy... Just pondering how those knives fare against wrinkly riped tomatoes

I am still waiting for some SEM pics from Clay & Sandia to clear up this fuzzy topic. This topic lured me here in the first place - Thanks Anthony Yan

Mean while, just to refresh where my head was... Took 2 box cutter blades. blade1 - stropped on a NEW bare horsebutt leather for 30 strokes at 10 lbs of pressure. Blade2 - stropped on a 7 months USED bare horsebutt leather for 30 @ 10 lbs. Snapped usb microscope 400x for each result. Doh, I didn't capture a pic for control/untouched blade.

Oh, I remember now. New bare leather won't do much because a bunch of tiny silicates too small to cause macro (micron level affect). Used leather where contaminated abrasives (dirty fingers )will abrade, while metal particle (from dirty fingers and came off the blade) will burnish. Other physical interactions are interesting but seem unlikely to have major affect in displacing steel matrix - especially high alloy where complex lattices & bonds will certain resist nano-level of molecular displacement/flow.



Just to be obvious - used bare horsebutt leather strop smoothened the bevel. I simple can't tell how much it burnished but quite sure it did - probably small part by abrasive and major part by swarf.

When shaping an edge with less than a few micron thick, regardless of stroke direction the abrasive must be within certain reasonable range, i.e. less than 20um. 100 grit is around 130um.

The Kasumi jigane is just soft iron, so this clad layer get abraded almost instantly. Now all the pressure will be concentrated on the core/hagane white steel. So using very low pressure is recommended, especially abrading with large hard blocky fixed abrasive (such as a diamond plate).

As for the kasumi haze use waterstones for that.

leomitch wrote:

Maybe I am optimistic but I perceive negative comments/rants are more than just 'squeaky wheels get the grease'/damaging/.. A good product + good cust-service shouldn't have any problem taking punches. WE is an excellent product + caring cust-service; however WE must shield growing pain from customers.

IHMO, 1 good resolution has more values than 10 praises. High-touch goes along with high-end products.

PhilipPasteur wrote:

first, with heavy pressure and if rounding occurred, it either dull and or entry angle into cutting paper will be more obtuse.

Draw 3 lines using marker from spine to apex, with 5mm gap between line. triangle1: dialed caliper to 0.25, insert into blade next to line 1, slice across line to mark the triangle base, aid with loupe measure the triangle side. Repeat for other 2 lines, with 0.5mm and 1mm respectively. Stropped and measure to check angles before vs after.

I also stropped using EP then checked using marker.


Once the angle maxed-out on the + a few degrees. That is the baseline angle. Since strokes at lower angle most likely won't hit the apex anyway.


My main goal for those videos was to make stropping simple, anyone can do it. Simple baseline is to make it sharps and not going dull when repeat & heavy pressure.


Percentage is subjective to how I tiered sharpness level. Tests & cutting styles are subjective also. 90% sharpness is threshold the edge cut or rip slice newsprint at 45* angle.


I do expect that you don't have any problem, since you use techniques that known to worked for you. Whereas 99.999% people in the world do not. In order for you to experience difficulty/challenge, that why I suggested go 20* inclusive or lower angle. When I pushed my Spyderco Stretch zdp-189 to 14* inclusive, its wire-edge is hell-ish to clean.


I posted how-to-make this stone on BF before. Basically heavy stock photo-paper, wet-it & wait, spread 0.1 polydiamond suspension/paste on it, heavy-pressure-roll-over using steel/ceramic rod to embed the diamond, wait 24hrs. Voi'la a stone which support edge-lead stroke (with care of course). You certainly can strop with this stone. Cost per 3x8 paper stone is around 10-20 cents, depend on diamond density. Oh, I did stropped on plain heavy-photo-stock-paper for 5 minutes, the coated white clay was too soft to abrade steel.

edit: here is the video where I used these paper diamond stones
youtu.be/ixfdpgbApuk

PhilipPasteur wrote:

Fresh sharpened an edge with dmt benchstone all way to 3um, measured angle with caliper. Rubbed on diamond charged strop, measured angle with caliper (iffy read) and use sharpie marker + loupe edge-lead on dmt EE.


I used/tried

1st - bulk white compound (probably alox) ferrous/stainless-steel rated at 1.2K grit. $5 per lbs.
2nd - Razor Sharp white compound (for slotted paper wheel), as I read - it's around 15um. $8 per 3oz.

Sharp is sharp

PhilipPasteur wrote:

I've applied this strop to many knives at least a month prior to my BF post & videos. Edges are around 90% durable compared to my edge-lead to 0.1um poly diamond stone. And not as clean (burr free) as edge-lead. I can switch back & forth between 2 approach for an edge and still hitting the apex (either manual or EP), so sort of confirm not rounding affect. Also from the paper cutting test, the edge entry cut angle remained low instead elevated even at heavy pressure. Oh well, there is no secret with this strop, so it's very easy to try to figure out whether it: worked or sort-of or not.


I really don't know my conjecture holds water or it's just a simple grasp a 'sound good' reason for why my edges not not look like a bunch of parabolas. I actually have another more far-out explanation but figured that my kevlar vest has poor coverage

I sure hope people try & tell me why - better than me flailing my arms theory/conjecture.


I agreed with you Phil. However there are many variables involve when we are talking about this type of stropping interaction. Hence with a right setup, you can get a perfect-storm to weaken the edge, but the norm for abrasive collides to steel in stropping (pushing away from apex) will has a slight chance of stretching/crack the steel/alloy lattice, which are undetectable or visible, until fracure when in use. In the larger scheme of thing, impact forces from cutting usually many magnitudes greater than a few moleculars weakening. I can see where edge-trail belt sharpening could crack/stretch at grain level, whereby this edge will perform poorly.


IF it works, maybe it can simplify WEPS strop configuration & enhance its effectiveness. Easy route of stropping success for WEPS's users.


Take a spyderco vg-10 or zdp-189 blade, strop with CrO 0.5um or 1um diamond at 0.5 lbs pressure. Oh do it for a few minute, I am sure you will get a wire-edge. To guarantee occurence, lower the angle to 20* inclusive. At this angle, I thinkg it's about 3x more difficult to get a clean edge without burr/wire/rounding.

leomitch wrote:

Summer breeze pressure, sure, it lightly abrades the bevel & ultimately controlling/trying/hoping:
1. not too much to cause backing flex upward to round the edge
2. abrading force vector to actually push/deflect the apex upward, thus create burr or a micro hollow just below the apex.
3. of course, enough force to actually cause abrasion and or burnish (plastic flow)

See - good reason for me to look for something to supports my (and 99.99% of cutlery users) Summer sneeze zero patience self like fast metal removal (when wanted so) and not rounding to edge

PhilipPasteur wrote:


I agreed, pressure controls the rate of metal being abrade from the bevel. Interestingly, pressure hardly induce rounding for this case. One of the major criteria/reason for demoing in this video. As I've repeated tries this strop vs diamond (16 micron to 0.1 micron). Starting around 12 micron the diamond loaded strop increase the rounding rate, reached maximum rate (per pressure against backing) around 6 micron. So 6um & finer abrasive it double my knife bevel angle - from around 30* inclusive to 60+* - proportional to the pressure. Corresponding to how much the backing flex upward. I observed the same for CrO & CBN at 0.5um.

W/o micrograph, I don't know how fine one can produce using this 'balanced / white compound strop'.

Sorry for delay show... I am out-of-town since friday, will be back late sunday.

For now, I will address the easiest question, why it's called a 'balanced' strop? Initially I want to call it a 'well balanced' as in well-balanced in gaming. A strop which offers these 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 via freehand or guided system such as EP/WEP

Balance = non demanding + support lo & hi skilled sharpeners + capture the bell-curve of good results (hence avoid nano-edges and rounded/dulled edge extremes).

I will read all questions again later and join the discussion. I made total of 4 videos, if time permits & interested please watch/scan them.
Part 1 - youtu.be/m8QhYFsXJwE
Part 2 - youtu.be/ujhB1IYedHw
Part 3 - youtu.be/pm9Cs3zVwt
Part 4 - posted by OP youtu.be/Q4O6boh0f2U

Edit: I also do think a stropped-edge is slightly weaker than edge-lead sharpened edge. However Cliff Stamp's assertion is way over-blown. That's said, he sure has much better credential+track-record than who-the-heck-is-blunt

I just want to clarify my earlier posts on convex edges - stated C in V, or V in C or V intersect C. For me, most of the time, convex means 'Practical convex'.



For 'Extreme', we are looking at nearly double or half the bevel angle. Even in the cases of micro-bevel - e.g. inclusive * 15/25 (67%); 20/30(50%); 30/40(33%) - we're far from doubling the angle. Stropped edges are mostly convex micro-bevel anyway

PhilipPasteur wrote:


Yes they were very intriguing, iirc from while back when I deep dive into these type of interactions. This older study linked by Thom Brogan via FF Haptic Rendering of Cutting. All these studies are confined by pseudo finite elements model, and most study material cells are too uniform, therefore I am not sure how much they translate to our knives usage world.

Back to convex - I guess it's up to one's interpretation what convex (curve and or angle and or shoulder). Also interpretation of performance for the 'what' V or C pros/cons; however studies/researchs such as above attempt to cover the 'why' fell short IMO. In WE world - bevel angle precision & repeatability - convex doesn't add much if your blade is thin behind the edge, a few micron micro-bevel will stable acute angle edge. If thick behind the edge, well thin it out (if has the mean), otherwise just blend the shoulder so there is less of an abrupt change from bevel to blade (the wedge - e.g. try to cut a crisp apple with scandi grind, hey don't cut it in hands unless you've bandage handy heheh.).

So far convex edge been depicted as V bevel fits inside C(onvex) bevel and with the same shoulder height (apex to where bevel end). On the opposite end, where C fits inside V, therefore C blended shoulder will be higher on the blade (more height). So C.in.V will have virtually the same angle at apex.

To me convex is more about no abrupt shoulder transition and bevel curvature. Curvature where could be optimize for max flow through material - think what shape a submarine/bullet/airplane-wing/etc yup mostly convex. I do micro-bevel my convex edge, angles depend on steels. Most of my edges (C and V) are too thin for steels anyway. Indeed blade with thicker behind the edge dulls faster -> geometry dictate that. Not so much about V or C, IMO. A common C probably intersect V some where near mid-point however C shoulder still higher than V.

Rocco's question about micro-bevel as a 2 S(egments) C(onvex). Note - SC apex is higher up in blade than apex of V. The dull rate of SC & V is the same when the damage (deformation/fracture) at or above the micro-bevel shoulder. If damage is short of SC shoulder, then performance of both SC & V proportionally degrade, merely more apex (flat top) resistance and proportional less bevel resistance.

Clear as mud

RoccoSanello wrote:


Peak 15x or 22x achromatic lens (colors corrected). Pricy but worth the $

You can generate mud by rubbing nagura stone or small diamond plate with your stone. Soft stone gets muddy fairly fast on regular sharpening interaction.

Because WE stones in-use are almost vertical, so mud & water have tendency to drip down. Similar to EP where stone is facing down.

I am speaking as a freehander. I had about 6 yrs with EP, zero with WE. So my opinion in this forum are of 1/2 cent type

Pure lapping = loose particles tumble along the blade/bevel surface.

Stropping is sort like lapping except most particles are loosely embeded, along with tumbling particles. Of course a lot depend on backing material (hard/soft <=> e.g. glass/leather).

More about mud = binder (resin/clay/etc) + broken down abrasives. If abrasive is high friable (like Alox/SiC), it usual get broken up during the course of collision. Easy test, just create some mud, take it, put on leather and strop for a while, you'll see the scratch pattern should be finer than the scratch from the stone directly.

I've rough language skills, so please don't mind my fumbling english.

PhilipPasteur wrote:


Hi Phil,

A moderate amt of mud in conjunction with fixed abrasives indeed would abrade & polish faster. My answer was for mud only (i.e. only loose abrasives), thus it's lapping not? For a same grit, lapping yield finer finishes - just like stropping is one directional lapping. I don't think we disagree, just viewing this matter at a different angle.

Geocyclist wrote:


IMO

mud/slurry = more polishing and much less abrasion than fixed abrasives because loose particles interact in a lapping fashion.

swarf (super fine pieces of abraded steel & carbides) = polishing, except for VERY (0.0001%) rare large carbide pull out chunk which is undersirable (i.e. big scratchy). I wouldn't worry about them at all just like you're not worried about those black stuff on your strops.