A balanced strop

[BluntCut MetalWorks]

Last PM before I/Blunt got bogged down with work & travel.

date: 20130827

Blunt, I had one other thought in this direction that I never tried before I peetered out and started going down the WB route. Based on the endgrain paper strop I thought that stacking some hard leather endgrain (side grain) might yield a hard enough surface yet still have the microtexture variations you're looking for. The leather could be boiled/cased first, stacked and trimmed very close to its support, maybe two angle plates laid lengthwise. Put some padding on the bottom leg of each angle and you'd have a crazy durable strop. Also (maybe), like the endgrian strop, if it did collapse under higher pressure it would be over a larger area and any convexing would be spread out by several factors over the relatively local collapse of flat leather. I am still dubious of gaining any sort of control at the cutting edge when it comes to polishing specific facets of the edge irregularities, the scale is just too small.

Martin

Hi Martin,

BS was seeded from your end-grain strop and again you're showing the way... I think your stack side grain leather idea could add a big improvement (albeit more time consuming to build). With finer & stiff texture, I think it may supports finer abrasive. Finer abrasive is needed if there is any chance of reducing the amt of cutting edge convex & rounding due to micron (and sub-micron) scale. I will try to make a small strop and hope it can support 1-3um (super fine) white compound.

For a while now, I couldn't find a suitable tiny rope with heavy short feathering, so I simulate the 2D + 3D by using fuzzy high quality paper towel over a mill file. It worked very well for variety of abrasives: AlO, SiC, CBN, Diamond down to 0.25um. With my 400x (more like 100x optical) microscope, I saw improvement and almost the novelty sharpness I seek. I think len cleaning paper(it would fuzzy up fast) would even be better and couple with a super fine file, maybe it will support abrasive at 0.1um in size. Maybe worth a close up?

Thanks,

==Blunt

Blunt, I have a bad feeling the type of 3D effect you are looking for can only be achieved through the abrasive itself. The effects of any physical carrier at that scale are almost always going to be blanket in nature. Its just too much ground to cover, and every pass hits in a random manner.
Have you tried backhoning on waterstones or jointer stones. Many disparage them on this forum, but the Norton waterstones are very good in this regard. The 4K backhone edge is very toothy yet can shave facial stubble. It is relatively easy to achieve burr free with this stone due to its composition - just a tad soft. This jointerstone

http://globaltooling.bizhosting.com/products/jointing-stones.html

230mm x 60mm x 15mm - 500 grit / DARK BROWN
Part # JS-2121 - SC5AC 500 Euro-Stone - Resin Bond

is the one I use. Between the Norton 4K and the above jointerstone came the target edge I was shooting for with the Washboard compound. I freely admit I fell a small bit short, but the Washboard makes up for it in convenience, forgiveness, and the ability to burnish the edge as a finishing step. My ultimate microtoothy edge is off the 4K or jointerstone, followed by the Washboard on plain paper. These edge last a long time at a very high level of performance.
The jointerstone has an advantage in being capable of dry use, when used with oil it only takes a half teaspoon or so, and is very inexpensive. I made a set of those jointerstones by adding a green silicon carbide for coarse work from the same page:

8" x 2" x 3/4" - 240 grit / BLUE-GREY
Part # JS-0500 - 39C 240-J,K,L,NV - Norton Stone [Specify Hardness wanted]

I used the "NV" which is the hardest one. As a pair these stones are fantastic for user edges, and the mud from the 600 grit (which performs much closer to a 800-1200) makes a perfect stropping compound on the Washboard or paper wrapped around the coarse stone. They can also handle any steel out there.
Just a thought, dont want to distract you from your line of 3D pursuit. I was unable to make headway on microtoothy edge until I "mastered" backhoning on these softer stones.

Martin

 

[BluntCut MetalWorks]

For frame of reference, below is an edge produced by Martin/HH's Washboard product using CrO (0.5um). Well, I won't post PM exchanges about my nit-picking stuff. What's really matter is the bevel is flat and edge very nice clean sharp edge :thumbup:


date: 20130819

Blunt, since I was at work and running well, thought I'd do a quick test with green CrO on the same knife I sent the earlier 600 grit pics. I used a single sheet and moderate pressure till the compound loaded up a bit, then reapplied to the same sheet - now with light pressure. Took pics, then stropped on plain paper, 25 or so passes with light to moderate pressure. maybe I could get a more uniform edge with more sheets, maybe not without rounding the edge? Bevels staying very flat. I'll have to do a few more tests to see what happens with more layers of paper - at some point there will be enough give that rounding will occur...
BF paper

After paper

 

[HeavyHanded]

I never did get back to that

Have been very busy at work lately....

 

[Chris "Anagarika"]

Thanks to both of you for the test and insight shared! Will be watching this thread closely :thumbup:

@ Bluntcut,

Just curious, the date posted on the PM quote seems to be backward (last one being 19 Aug, while the first was 26 Aug?)

 

[mycough]

I tell you what, this works. I can't believe how close to foolproof it is and coming from me that means something. Russ

 

[BluntCut MetalWorks]

I've been using an improved strop substrate/surface for a few weeks now. It's less convexing than flesh/nap-side of leather and sisal rope surfaces. Plus it gets my zdp-189 blades super sharp clean edge every time.

Felt from home center ($3 for 2 4x6" pads). Strop strip as pic (1.5x6").
1. Cut & adhere to wood.
2. Spray felt with water (thoroughly wet).
3. Hard smear 1/3 to 1/2 oz of Gorilla glue (the type that bubble when curing) into felt.
4. 1hr later ...
5. rake with hack saw blade.
6. Generously apply white compound.

* Clean swarf (a few times before recharge)
a. scrape off the black stuff with knife spine.

* Recharge
a. Clean swarf then apply white compound

* Resurface
Do steps 5 & 6 above.



** note **
This strop is effective for blade with little or no Vanadium & Tungsten carbide.

 

[Chris "Anagarika"]

Using old strop + autosol ... Back to basic

End grain cardboard will help minimizing rounding ... Having said that, I still use balance strop from time to time