Stropping and "Toothy" Edges

[ncrockclimb]

Over the last 18 months I have learned a lot from this forum on how to sharpen. Thanks to other members sharing their experiences I have been able to improve my skills and can get a decent edge on my knives with a variety of methods. Thank you to everyone that has helped me by posting good info here!

Lately, I have been using my KME and stopping at either the 300 or 600 diamond hones. I then do some light stropping with either Stropman black compound on leather or the finer Flexcut Gold. My goal is to get a slightly toothy edge that will slice fibrous material but still shave arm hair. However, I am wondering how much my stropping is destroying the "toothyness" of my edge and dulling it. Should I stop stropping all together? Should I stop at 300 or 600?

Also, I am wondering how I should be touching up my blades between KME sessions; should I strop or freehand on a DMT coarse / fine?

Finally, is the consensus still that "toothy" edges will hold an edge longer? I have done some searches on the subject, but there is a lot of dogmatism and a sparsity of data on the subject.

 

[uofaengr]

I've been watching lately a YouTuber by the name of Michael Christy, might be a member here, and he tests a lot of super steels and shows how he sharpens them. He calls his finish a coarse finish yet does a lot of stropping. I think his typical progression is Spyderco diamond, medium, fine, extra fine rods, then like maybe 4 to 6 different strops often going to 0.1 micron or maybe further.

I don't know if he means coarse by the stones jump a few grits or what. He says the edges have a lot of bite after all that refinement but having a hard time believing there's much tooth left to them when he's finished. I wouldn't think stropping your coarse edge is killing it's toothiness, but would guess if you stropped excessively it could affect it some.

 

[The_Iron_Joe]

I've been watching lately a YouTuber by the name of Michael Christy, might be a member here, and he tests a lot of super steels and shows how he sharpens them. He calls his finish a coarse finish yet does a lot of stropping. I think his typical progression is Spyderco diamond, medium, fine, extra fine rods, then like maybe 4 to 6 different strops often going to 0.1 micron or maybe further.

I don't know if he means coarse by the stones jump a few grits or what. He says the edges have a lot of bite after all that refinement but having a hard time believing there's much tooth left to them when he's finished. I wouldn't think stropping your coarse edge is killing it's toothiness, but would guess if you stropped excessively it could affect it some.

No way that's a coarse edge after all that...

 

[ncrockclimb]

I've been watching lately a YouTuber by the name of Michael Christy, might be a member here, and he tests a lot of super steels and shows how he sharpens them. He calls his finish a coarse finish yet does a lot of stropping. I think his typical progression is Spyderco diamond, medium, fine, extra fine rods, then like maybe 4 to 6 different strops often going to 0.1 micron or maybe further.

I don't know if he means coarse by the stones jump a few grits or what. He says the edges have a lot of bite after all that refinement but having a hard time believing there's much tooth left to them when he's finished. I wouldn't think stropping your coarse edge is killing it's toothiness, but would guess if you stropped excessively it could affect it some.

I think I agree with that. EX Fine then strops is anything but toothy in my book. I have come to think that the Spyderco Medium rods are pretty fine. However, toothy vs smooth is relative I guess...

 

[uofaengr]

His edges cut hair at the slightest touch, slice TP and paper towels. I haven't experienced a coarse edge that can do that.

I recommend taking a look at some of his videos. Some interesting stuff for sure, and he has a unique sharpening technique.

 

[ncrockclimb]

His edges cut hair at the slightest touch, slice TP and paper towels. I haven't experienced a coarse edge that can do that.

I recommend taking a look at some of his videos. Some interesting stuff for sure, and he has a unique sharpening technique.

I will definitely do that! I am sure I can learn a lot from someone who can create that kind of an edge.

 

[uofaengr]

I think I agree with that. EX Fine then strops is anything but toothy in my book. I have come to think that the Spyderco Medium rods are pretty fine. However, toothy vs smooth is relative I guess...

One of my favorite edges I've personally done is 1000 grit then just a few passes with 3.5 or 1 micron. It reminds me a lot of the Spyderco factory edge based on feel though I know mine is a bit more refined. I prefer more of a sheen than a mirror so it's a good balance of aesthetics, which is not my primary motivator, and has a lot of tooth left.

IMO taking a knife to that level of refinement is a lot of work for something that's going to lose that level of sharpness in the first pass through cardboard. I just prefer a more toothy edge these days and find it much more useful.

 

[HeavyHanded]

Most of the time the toothier edge will last longer for everyday usage. When drawn across a material with some force applied, the toothier edge will generally part it with a lot less applied force than a more refined edge being pushed into the same material, and even if the more refined edge is drawn in the same manner. Type of steel will effect this as will a few other variables, but generally speaking...

Some materials do not part well with a draw and the tooth will then increase the amount of resistance when the edge is pressed into a material. Hatchet, machete, Chef's knife - more refinement = longer lasting edge when used with a shop/shave/pressure cut. If you take that refined edge and pull it across a bunch of materials it will lose its longevity boost. Same with a toothy edge if you force it through a material ill suited for a pressure cut - it is pressure into the cutting edge that makes it dull, so whatever edge finish reduces this is the better choice.

Harder backed strops will produce toothier edges. If your strop is too conformable it will not only eliminate the tooth, but increase the odds of micro-rounding the apex, especially over time. If toothy is the goal, use the hardest backed strop you can that does not produce burring or use a second step to remove that burr.

To get the best toothy edge at a given stopping point, strop only with paper - plain paper over a stone or similar. This will reveal any latent burrs by shining them up, and will preserve the tooth formations.

I created the Washboard specifically to address this, I wanted the convenience of a strop for maintenance, but a microtoothy edge finish.

Harder backing is better till it gets too hard to do a clean job or issues arise between the abrasive, binder, and stropping surface.

 

[MichaelMyers]

There's almost zero tooth left after Spyderco medium.

 

[Obsessed with Edges]

Over the last 18 months I have learned a lot from this forum on how to sharpen. Thanks to other members sharing their experiences I have been able to improve my skills and can get a decent edge on my knives with a variety of methods. Thank you to everyone that has helped me by posting good info here!

Lately, I have been using my KME and stopping at either the 300 or 600 diamond hones. I then do some light stropping with either Stropman black compound on leather or the finer Flexcut Gold. My goal is to get a slightly toothy edge that will slice fibrous material but still shave arm hair. However, I am wondering how much my stropping is destroying the "toothyness" of my edge and dulling it. Should I stop stropping all together? Should I stop at 300 or 600?

Also, I am wondering how I should be touching up my blades between KME sessions; should I strop or freehand on a DMT coarse / fine?

Finally, is the consensus still that "toothy" edges will hold an edge longer? I have done some searches on the subject, but there is a lot of dogmatism and a sparsity of data on the subject.

Lately, I've been experimenting with a DMT Coarse (325 mesh/45µ) to apply more 'toothy' edges to a few knives. Among them, Spyderco's S90V (Manix2), a CRK Sebenza in S30V, and I've also been doing this to a few of Case's blades in CV and their 'Tru-Sharp' stainless (420HC). The only stropping I've done to these is on the rough side of a leather belt with some green compound; just enough passes to scrub residual light burrs away. All of these edges will easily shave arm arm hair, but still retain some great bite. I'm even contemplating doing the same routine with a DMT XC, to see how those edges perform; the results from the Coarse DMT were that encouraging.

If you're worried about over-stropping and taking the tooth out of your edges, try something less aggressive than the black compound or any aluminum oxide compounds (like the Flexcut Gold), both of which will be much more aggressive polishers than something like green compound. The greater impact on the edge's performance (shaving, slicing coarse/fibrous materials) will come from how much you refine the edge before you strop it, after which any stropping should be minimal and only enough to clean up light burrs left over. Green compound can be just aggressive enough to do that without running the risk of overpolishing the edge, even if you go a little crazy with the stropping. Aluminum oxide compounds can be great for refining on strops, but they're MUCH faster to polish (& overpolish) if the stropping goes on too long.

I don't universally believe a coarser edge will last longer than a more refined one. Too much depends on other variables, like steel type, geometry and what you're cutting (& how you're cutting). I mention this, because I have an older Case 6265 SAB Folding Hunter (~1965 vintage in their simple carbon steel now known as 'CV'), convexed and polished up to/thru 2k+, and tested it by slicing up a cardboard box into ~3/4" strips, after which it still easily shaved hair off my forearm. I never would've seen that coming, as the steel felt very, very 'soft' on the sandpaper when I'd convexed it, and I didn't expect a hair-shaving edge to last after doing any real cutting with it; but it did. That was an eye-opener, and it convinced me there's no hard & fast rule about edge durability, when only comparing a 'toothy' edge to a 'polished' or 'refined' one, and ignoring all the other factors affecting it.


David

 

[HeavyHanded]

I will also add that stopping at a relatively coarse to medium finish and 'steeling' the edge on a smooth steel, borosilicate or soda glass will also make a great "toothy" edge that will have a good qualities across the board. There are a lot of ways to get there, keeping it there easily over the long haul is the harder part.

 

[me2]

You can meet your goals of toothy but arm shaving with just a stone.

 

[ncrockclimb]

...The greater impact on the edge's performance (shaving, slicing coarse/fibrous materials) will come from how much you refine the edge before you strop it...

Can you please explain what you mean by "refine?" I always think of refine meaning using higher grits and polishing the edge. However, I don't think that is what you are talking about here.

Thanks!

 

[Obsessed with Edges]

Can you please explain what you mean by "refine?" I always think of refine meaning using higher grits and polishing the edge. However, I don't think that is what you are talking about here.

Thanks!

By 'refine', I'm talking about getting the apex as thin and clean (free of burrs) as possible, leaving only strong and sharp steel at the edge. That's basically independent of the the finish used (coarse, medium or polished), as both coarse and very polished edges can both be very refined in their own right, when done correctly. They'll each perform differently according to finish, but still cut effortlessly and durably.


David

 

[ncrockclimb]

Thanks for explaining. How to you get a coarse edge to be refined? How is it any different than refining a polished (or any other) type of edge?

 

[Obsessed with Edges]

Thanks for explaining. How to you get a coarse edge to be refined? How is it any different than refining a polished (or any other) type of edge?

For coarse edge refinement, it's done mostly on the stone, finishing with very, very light passes and/or raising the angle just a little bit to scrub burrs away. Any stropping to follow is very minimal in terms of actual polishing, assuming preservation of toothy bite is the goal; the compound that might be used should not be too aggressive in polishing the steel, but only enough to scrub away any remnants of burrs and/or align the teeth in the edge.

This differs from 'refining' a polished edge, in that the compound would be chosen and used for higher polish while also thinning the apex further, as might be done for a true shaving edge.


David

 

[ncrockclimb]

Thanks for the explanation. I have read about (and tried) slicing through a piece of wood to remove a burr. Is that a good technique or not?

 

[Obsessed with Edges]

Thanks for the explanation. I have read about (and tried) slicing through a piece of wood to remove a burr. Is that a good technique or not?

I've only found it to work reliably if the burr is already very fine, in which case many different means can usually scrub them off; even cutting paper can do it at times. Some more ductile steels I've tried (420HC at slightly lower hardness; and even VG-10, ATS-34 up to ~60 HRC) just don't respond to it, if the burrs are very heavy at all. In particular, heavy burrs on ATS-34 and VG-10 have just laughed at the method when I've tried it for these; they seem to need some dedicated & careful abrasion with fairly aggressive stones and/or stropping compounds to get the burrs off.


David

 

[HeavyHanded]

Can you please explain what you mean by "refine?" I always think of refine meaning using higher grits and polishing the edge. However, I don't think that is what you are talking about here.
Thanks!

As Dave says, light pressure and just clean up the burr. I highly advise stropping on plain paper for coarse edges (especially) as this can align the low spots along the edge without rounding over the higher points. Wrap the paper over the coarse side of a combination stone and you can actually use a bit of force, resulting in a bit of burnishing taking place. This also polishes up residual burrs and lets you see quickly where the edge might need a bit more TLC.

I also have to recommend again the use of a smooth steel of some sort on coarse edges as this actually will "refine" in the traditional sense - the distance of the edge across will become smaller - yet the irregularities that make the edge grabby will remain. In steels with fine grain/low carbide content this will yield a frightfully effective edge with very little time invested.

Thanks for the explanation. I have read about (and tried) slicing through a piece of wood to remove a burr. Is that a good technique or not?

In my experience this only works well under two circumstances - when using a belt grinder to sharpen the burrs tend to have extremely small attachment points and respond well to have the bulk "torn" off on some endgrain wood. This might not work so well for final detail burr removal, but for hasty work between progressions it works well.

The other instance is when it is used often, every few passes and as one swaps sides. On a hard stone I normally will just deburr with light leading passes. On surfaces like wet/dry or softer waterstones it is possible to make a backhone pass or two, lightly drag on wood, flip and repeat. It can take a number of passes to eliminate the burr but it tends to be quite effective. If one waits to the end and attempts to pull off a normal/smallish burr in a drag or two or three it generally does not work well if at all.

The biggest drawback to this method IMHO is the likelihood of debris - either residual grit or bits of steel winding up in the wood and etching tiny grooves parallel to the edge. This may or may not weaken the edge, but makes it tough to tell if you're looking at a microscratch or residual burr.