Help with edge aggression!

[HeavyHanded]

I never got much edge improvement when stropping on plain paper (perhaps some after 200 passes)until I applied slurry to it. Then I noticed a step up in improvement when stropping on leather with the same slurry applied. I think the pores in the leather hold the slurry better. If you don't let the blade get closer to dull then stropping is an effective edge maintenance and saves steel on your blade. Thanks for posting the series of photos and all the effort sharpening that went in to it. Different stone binders will leave a different looking and cutting edge than coming off sand paper. Plus the difference of edge leading or edge trailing strokes. Then I've noticed an edge is capable of push cutting sisal rope coming off a 320 grit Norton India stone. DM

All very true, until I started using real hard backing, I never saw a ton of improvement stropping on paper unless the edge was very refined to begin with. As pressure goes up, I realized I was actually burnishing the edge to some extent but never realized how much till I took the pics. I honestly don't think you could generate those kinds of pressures on a regular stone wrapped with paper.

The Norton India stone is capable of some very fine edges compared to its rated grit value - very clean and tight grind pattern. Sandpaper is not the best demo abrasive, but not bad, especially for discussing edge effects. Have to start somewhere. That India stone is a heck of a tool.

 

[HeavyHanded]

Wow, thanks for the photos HH! you def. have technique down if you can do that all by hand! what kind of microscope/metallograph you using?

I think those photos demonstrate exactly what happens in a toothy vs polished edge.

This is the microscope - not the best, but pretty good for the money:
http://www.amscope.com/me300tz-5m.html

I did this work-up at the request of a couple of friends from the Washboard vs CS Recon thread. I know the videos are tough to sit through, but the technique used to make those pics was exactly from the videos - could be applied to a number of abrasive media. I think I do a pretty good job explaining if you can make sense of my mumbling - ouch

 

[David Martin]

I understand --now. A very good effort. DM

 

[Chris "Anagarika"]

HH,

What would happen if the edge of the last pics is brought back to washboard + Flexcut?

I think it should put back some teeth, based on my test (but not having microscope to check).

 

[HeavyHanded]

HH,

What would happen if the edge of the last pics is brought back to washboard + Flexcut?

I think it should put back some teeth, based on my test (but not having microscope to check).

Even the Flexcut that was used on leather to help make that edge, will react with more aggression on the Washboard - leave an easily visible scratch pattern. Would definitely put some bite back into the edge. I gained a lot of understanding re this when I was lapping on hardwood with different compounds, how changing the backing allows the abrasive to "express itself" differently. Could apply three sheets of paper and probably get the smooth expression from it, then switch to one sheet and get the more aggressive expression.

HH

 

[SirSharpSauce]

So should I strop with a hard backing or a leather one, tip to heel or heel to tip, as someone mentioned?

My leather stropping could be the reason for my unaggressive, rounded edges.

 

[SirSharpSauce]

Has anyone had experiences with balsa wood strops?

 

[HeavyHanded]

So should I strop with a hard backing or a leather one, tip to heel or heel to tip, as someone mentioned?

My leather stropping could be the reason for my unaggressive, rounded edges.

Try tip to heel, or work in sections. Just wrap a sheet of paper around your stone, a coarse stone works better than a smooth one, and apply compound to that. Toss it when it loads up. Also, there are many grades of polishing compound out there. Use one that's labeled for stainless steel, not for a final polish. If you want an aggressive edge, you want to see some haze to the scratch pattern, not a super fine polish. Ryobi and Sears make pretty good black compounds that are maybe too coarse for what you want but maybe not. They come in handy for a final pre-polish for maintenance stropping if the edge is a little worn. Then move on to a white or yellow.

You can also just strop on paper after coming off a fine stone, don't use a compound.

 

[Novaculite]

HH, thanks again for these incredible photos.
As far as polishing-before-slicing is concerned, countless experienced knife sharpeners have suggested working from a coarse stone up to a middle grit, something like a 1000 on the Japanese scale, and stopping there. Finish with a few strokes on a strop to drop off the burr, go to work in the kitchen and use a steel to maintain the edge for a few weeks before returning to your stones. The somewhat coarser edge acts like a micro-saw and will work its way through a tomato skin and a few other things easier than a highly polished edge of the HH-caliber we can see above. Give it a try, doesn't cost anything and may even help. I've split hairs before, could do it again, but honestly need that kind of sharpness only when shaving, not in the kitchen.

 

[HeavyHanded]

HH, thanks again for these incredible photos.
As far as polishing-before-slicing is concerned, countless experienced knife sharpeners have suggested working from a coarse stone up to a middle grit, something like a 1000 on the Japanese scale, and stopping there. Finish with a few strokes on a strop to drop off the burr, go to work in the kitchen and use a steel to maintain the edge for a few weeks before returning to your stones. The somewhat coarser edge acts like a micro-saw and will work its way through a tomato skin and a few other things easier than a highly polished edge of the HH-caliber we can see above. Give it a try, doesn't cost anything and may even help. I've split hairs before, could do it again, but honestly need that kind of sharpness only when shaving, not in the kitchen.

Glad you found the pics interesting - takes more time to get the pics right than it does to sharpen the knife.

The above statement really sums it up. In my kitchen set I have a big Chef's knife that is polished up to a pretty high level - not the super polish in the last pic (I never bother with that anymore), but the second to last one off of my homebrew compound and burnished on paper. It can pushcut tomatoes, but that's not what I use it for - its strictly for chopping, dicing, mincing.
My utility knife is kept at the 600 grit level and that's what I use for opening food packaging, trimming meats etc. I'll jog up a handful of green beans and instead of snapping all the ends off one by one, I just give it a quick draw cut and nip 'em all at once. Also good for slicing tomatoes.
I keep my EDU knives at the third to last pic - off the homebrew compound without the extra step of burnishing. Still microthoothy, but capable of fairly fine cutting and good longevity for how I use them.