A balanced strop

I think the objective is to use it more like a finishing waterstone than a traditional strop. You get the benefit of maintaining the edge with specific characteristics, rather than constantly bouncing from sharp to no-so-sharp, or with the slowly mutating characteristics of maintaining on a traditional strop - where you eventually have to go back to a stone regardless.
 
So maybe I'm just not understanding this over complication, I fully understand the concept of coarser stropping I often use a 15 Micron CBN on Roo leather with excellent results. Although it is no replacement for a fine stone simply because of its lack of aggressiveness and firmness.
 
I think that's part of it. The manila is a bit more firm than leather, and holds a lot more compound. Its all a variation on how conformable the backing is, how much mobility the abrasive has, and how the abrasive reacts to the steel in question. The 'balanced strop' concept is looking to get strong results with the most convenience and largest margin of error. In many respects this is a simplification of the process, you can go from a relatively coarse grit stone for bevel setting and your finish step is also the maintenance step - similar in concept to a 1k - 6k waterstone setup (or in this case, maybe an 800 - 4K). The manila, being conformable, gives a greater margin of error than a waterstone, yet is firm enough to make a largely unrounded edge while being very easy to produce and transport (rope and compound).

I've been known to dabble in this concept from time to time myself;), but have yet to match my waterstone edges by any other means - no longer think its possible, but can come very close.
 
knifenut1013 said:
First, the above edge has a burr.

Second, abrasive size of white compound in in the single digits.

And third, what's the point of stropping for so long? That just tells me the edge wasn't good enough from the stone.
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1st - You could be right or it was just light scatter from cheap usb microscope because IIRC that edge sliced (dozen cuts) newsprint all direction pretty smoothly and then shaved with some burns. Not that hard to reproduce such edge anyway.

2nd - Initially I looked into it and then triangulated with emperical data then determined that AlO abrasive about 12-15um. In some later posts - SharpAndSafe researched but can't pinpoint exact size, so settled for abrasive size is in 12-15um range. Jason - if you have hard data on your claim, please share.

3rd -
HeavyHanded said:
I think the objective is to use it more like a finishing waterstone than a traditional strop. You get the benefit of maintaining the edge with specific characteristics, rather than constantly bouncing from sharp to no-so-sharp, or with the slowly mutating characteristics of maintaining on a traditional strop - where you eventually have to go back to a stone regardless.
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:thumbup: sir!
 
I had way too many dry-shave with edges off this strop - with result from great to pain. So I made a few straight razors and see this strop's limits
razors20130516small.jpg

* inclusive degree

1. AEB-L (razor/surgical stainless ~60rc) : my current go to razor
a. 12*, 15*, 22* => burrs = failed
b. 22* (progression 1K, 4K, 8K waterstones 1,0.5,0.25,0.1um diamond paper stones all in edge-leading strokes, bare leather) => clean smooth dry shave better than disposable 3 blade razors. I will regrind this to lower angle for testing later.

2. ZDP-189 dragonfly (66rc): was my primary shaver for awhile until demoted
a. 14* => burrs
b. 18* => clean

3. CPM 3V (~60rc)
a. 10*, 15* => burrs
b. 20*+ => clean

4. CPM 3V blank - waiting for my Evenheat KO HT oven to arrive then will compare this edge vs #3 (which ht by a brick forge & gas cooking burner)

5. 52100 (~60rc): steel was all pitted-up before I made this razor but I did it anyway to test.
a. 10*+ => clean. It would has been usable if the edge was pits free.

6. 15N20 (~58rc): A 10.5cm petty. yeah, I test knives to find performance boundaries too
a. 8* to 20* => clean shave & slice/push phonebook paper. Rolled when make 2-3mm thick shavings from pine board
b. 26* => clean shave & no roll on cardboard, pine shaving, chop hard vegies.

For me, burrs or wire-edge = failed for this combination (blade steel + ht + this strop + angle).

So this strop is quite versatile for majority of practical non-facial-shaving edges.
 
knifenut1013 said:
I've googled it before and posted many links the last time the question of abrasive size per white polishing compound. It not all that hard to find.

But here, this will get you started. http://www.ganoksin.com/borisat/nenam/buffing-material.htm
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I found this article un-informative. Also questioned the author credibility by this excerp
"
Chrome oxide (chromic oxide)
A green, insoluble powder (Cr2O3).Very little abrasive effect - used in green rouge.

Aluminum oxide (Alumina)
Very little abrasive effect - used in white rouge
"

Well, we all know Cr2O3 is very abrasive. Similarly Alumina (most commonly found in synthetic waterstones) also very abrasive.
 
When it comes to polishing compounds I suspect all the white ones are in the single digits. It is possible to get AlumOx in much larger grit in the form of black compounds, and a huge variety of AlumOx in high purity (white) can be from sources as varied as microdermabrasion supply houses to homemade lens manufacturing for telescope lens grinding/polishing. Pretty sure 300 grit and higher is no problem (I have a container of 25u and 5u on my bench at work), but these are dry powders, not compounds. I also suspect there are other properties involved that make some of the "polishing" grit unsuitable for stropping due to particle shape, at least not without solid understanding of the variables and some form of powered equipment (eg microtome grinders).
 
HeavyHanded said:
When it comes to polishing compounds I suspect all the white ones are in the single digits. It is possible to get AlumOx in much larger grit in the form of black compounds, and a huge variety of AlumOx in high purity (white) can be from sources as varied as microdermabrasion supply houses to homemade lens manufacturing for telescope lens grinding/polishing. Pretty sure 300 grit and higher is no problem (I have a container of 25u and 5u on my bench at work), but these are dry powders, not compounds. I also suspect there are other properties involved that make some of the "polishing" grit unsuitable for stropping due to particle shape, at least not without solid understanding of the variables and some form of powered equipment (eg microtome grinders).
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What abrasive type & size do you think this 1200grit compound (use by this balanced strop)?
http://usaknifemaker.com/buffing-supplies-c-55/buff-compound-white-cut-and-color-3lb-bar-approx.html

There are AlO grind belts grit from 36 to 3000, so I think it might be possible to have AlO in compound form in that range?

I also use this compound for polishing hard wood (honduran rosewood recently) knife handle with great result.
 
I really couldn't say. I've had good success mixing some of the bar compounds with a bit of mineral oil and applying to a slide for microscope. AlumOx looks like a whitish crystal, even the stuff that's in the black compound (at least from Sears and Ryobi). As purity goes down, the color apparently becomes darker. A generic polishing compound like that could easily have several abrasives and in a range of sizes starting from the stated 1200 grit and going down. Usually costs a little more to get accurately graded stuff, rather than a mesh value which implies "nothing larger than YYY". Might even be tin oxide, but we're in an area where I have very little more to contribute beyond pure speculation.
I have to caution against drawing too many conclusions from the microscope in terms of edge condition. There's more you can't see than what you can, even with my good microscope at work - lighting effects, focal depth, backlighting....Can't deny cut tests, but then I've noticed a lot of variation in how some of these "assertive" strops work with various abrasives and on different steels, profiles, etc. Takes a lot of testing to really see the trends - in my experience it excels in some cases and falls flat in others, there's always a trade-off.
 
I did more stropping, and yes, it does get smoother. I guess this balance strop works for me.

I don't have microscope, or extra fine polish need (plus my knives are of medium steel), so the level of refinement is enough for my use.
 
For the last few months, I've mostly utilizing a balanced strop to refine-sharpen & strop all my knives. So, my diamond suspension & compound were collecting dust.

Well, last night I sharpened this new knife I made for my friend 60th bday. Progression: 80 ceramic, 140 diamond plate, dmt CFE, ghessin 1K, king 6K, balanced-strop. At this point, this knife can almost push cut cross grain phonebook paper. Since sharpening was very easy due to fine grain steel at high rc. I decided to strop on 0.25um monocrystalized diamond for about 90seconds, then jump to 0.1um polycrystalized diamond for another 90 seconds. Now, the edge scared me for a moment as I test cuts(7 times) almost empty paper towel roll with almost no resistance. Easy stubble shave. push cut phonebook paper all directions, tree-top hairs.

While waiting the saya (think sheath for kitchen knife) to dry. I wrapped the blade with a piece of paper towel (costco), so 6 layers of paper covering the edge, and hold together by 2 rubber band. I'm polishing the handle with white-compound while holding the blade. Oh what-the-heck both rubber bands broke, too late the blade cut through the paper layers + rubber band + a bit of skin.

pxuz.jpg


Steel 52100, 0.093 thick, 4.25 cutting edge, distal tang, distal blade, stock removaled, Evenheat digital oven tripple quenched + a 1500F final harden quenched cool to 10F, double 2hrs tempered at 400F - 62rc, 0.019 behind the edge, handle: zebra wood with 3 hidden stainless pins along with red+white+blue liners, saya: shedua wood. Blade is pressure fit into saya, so it can carries upside down.
 
Let me be the first to say what a beautiful knife, handle, and the saya turned out. I love the look of natural wood on a knife, and you have mastered it with this work of art. I would love to own it, but it would be a "safe queen" for me as I could not bring myself to use such a gorgeous knife. Your friend is one lucky gentleman.

Blessings,

Omar
 
OHALLUM said:
Let me be the first to say what a beautiful knife, handle, and the saya turned out. I love the look of natural wood on a knife, and you have mastered it with this work of art. I would love to own it, but it would be a "safe queen" for me as I could not bring myself to use such a gorgeous knife. Your friend is one lucky gentleman.

Blessings,

Omar
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Thanks Omar!

I made this knife for high performance. I am counting on my friend use it extensively + some mis-uses. Before handed the knife over... Shhhh! I did a little side-by-side cardboard & wood whittling test this knife against a Spyderco Gayle Bradley. This knife 10, GB 9 - look like I have to make more 52100 knives for re-test. heheh I will double sub-zero quench next blades. Double Cryo thereafter. Pushing for 63+ rc without compromise toughness.

I stropped my v2 24cm 63rc jknife on 0.1polydiamond, got a fast wire-edge. Same result for skd11 64rc yoshikane knife. However both knives responded well with balanced-strop. I need to figure out whether stropped this new knife on diamond was a one-time fluke sharpness or repeatable due to reasons.
 
Congratulations to you (beautiful blade!) and your friend (he's lucky to have you as his friend!)

I guessed earlier you'd be a knife maker soon :D

I am still a faithful follower of the balance strop. Last I did was a SAK, and it also performs well (lower HRC, I guess 54-55). So it can be quite a 'universal' strop to improve an edge, regardless of HRC.

BTW, how did you press fit the blade to saya?
 
Thanks Chris & David!

Making knives hobby is fun, also I'm learning more on how metal+ht response to sharpening.

Pressure fitting saya: glue wood spacer to bottom panel, put knife in the form, sand to 110% height (flush + 10% gap), glue thin g10 spacer patches to middle & tip of bottom panel, glue top panel. Put sandpaper over a hack-saw blade, sand down g10 to the target pressure fit. For glue, I used Cyanoacrylate. Drill 6 hole for pins, epoxy them. Pretty up the F&F.

:thumbup: Chris for sticking with Balanced-Strop. It's very versatile & quite fool proof. I will continue to use it extensively since it surpasses my practical sharpness requirement and also achieved 3D refinement. Hard backing & stone are 2D sharpeners - mostly affecting the surface, skipping over between teeth/gap/trough.
 
Great looking knife and saya! I've the same thing happen to me with the paper towels and rubber bands. LOL Now, if need be, I use a hard paper knife sleeve and a smaller quick clamp to clamp onto the blade so I have something to hold on to.
 
Thanks pj!

My laziness almost draw blood, I'll use hard cardboard to cover the edge next time.
 
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