Is stropping all that it is cracked up to be?

J

j.man

Joined
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I saw this post on http://edcforums.com/threads/toothy-vs-polished-edge.106484/ and was wondering if there is any truth to this?

Also (I'm sure to get lots of disagreement on this one) but stropping is the enemy of edge retention depending on what you're cutting. A barber can get away with stropping a razor because all he cuts is hair, but if you were to take a barber's razor and cut cardboard with it you would destroy the edge. You can get a knife just as sharp with a high grit stone as you can a strop, and get a much more stable and refined edge that will last much longer. If stropping gives you the perception that your edge is getting sharper than when you finished with your stones, then you aren't leaving the stones with a well refined edge to begin with. In other words, your work on the stones needs more work. Strops only bend and stress the teeth on an edge, and so they may stand up those teeth and give you the perception that the edge is stronger, but they're making the edge weaker in the process. By comparison, on an equal grit stone you cut the teeth instead of standing them up, and end up with a much stronger refined edge that will last drastically longer regardless of what grit you actually sharpen with.
 
While I can agree with Some of what he says, I cannot agree with his conclusions in the last 2 sentences. Too many experienced, knowledgeable knife persons have already proven that a coarsely sharpened edge cuts longer. DM
 
j.man said:
I saw this post on http://edcforums.com/threads/toothy-vs-polished-edge.106484/ and was wondering if there is any truth to this?

Also (I'm sure to get lots of disagreement on this one) but stropping is the enemy of edge retention depending on what you're cutting. A barber can get away with stropping a razor because all he cuts is hair, but if you were to take a barber's razor and cut cardboard with it you would destroy the edge. You can get a knife just as sharp with a high grit stone as you can a strop, and get a much more stable and refined edge that will last much longer. If stropping gives you the perception that your edge is getting sharper than when you finished with your stones, then you aren't leaving the stones with a well refined edge to begin with. In other words, your work on the stones needs more work. Strops only bend and stress the teeth on an edge, and so they may stand up those teeth and give you the perception that the edge is stronger, but they're making the edge weaker in the process. By comparison, on an equal grit stone you cut the teeth instead of standing them up, and end up with a much stronger refined edge that will last drastically longer regardless of what grit you actually sharpen with.
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I would love to see micrographs of the teeth on an edge sway back and forth due to stopping on anything but a stone or hardwood. The perception that stropping destroys an edge is (mostly) due to the edge rounding in the hands of whomever is proposing the idea. Even microscopically this will effect the cutting characteristics of an edge. I have also seen detailed scientific analysis of why stropping ruins an edge (done with a 200x microscope! - I'm reluctant to draw conclusions at 640 or even 1000x). The truth is that "stropping" can have many definitions, from backhoning on a waterstone to the more traditional stropping on plain leather. It can produce a toothy or refined edge, remove a lot of steel, or impart a very light polish. It is, or can be, very critical of changes in angle or pressure.

The largest difference is that the stone work will leave a more defined tooth pattern under most circumstances (but not all). It is entirely possible to finish with a very catchy, toothy edge from stropping, but not if you don't understand what is happening. It is also far easier to maintain an edge over the long haul on a strop if you understand the limitations. Every time you put stone to steel, you now have a burr to deal with and are removing more steel by comparison.

Bottom line, it is impossible to make a blanket statement without going into a lot more detail. I would agree that at very low grit it makes no sense to strop, but once you break the 300 or so range, it can make for a lot of improvement and edge retention (or not depending on how you approach it).
 
j.man said:
I saw this post on http://edcforums.com/threads/toothy-vs-polished-edge.106484/ and was wondering if there is any truth to this?

Also (I'm sure to get lots of disagreement on this one) but stropping is the enemy of edge retention depending on what you're cutting. A barber can get away with stropping a razor because all he cuts is hair, but if you were to take a barber's razor and cut cardboard with it you would destroy the edge. You can get a knife just as sharp with a high grit stone as you can a strop, and get a much more stable and refined edge that will last much longer. If stropping gives you the perception that your edge is getting sharper than when you finished with your stones, then you aren't leaving the stones with a well refined edge to begin with. In other words, your work on the stones needs more work. Strops only bend and stress the teeth on an edge, and so they may stand up those teeth and give you the perception that the edge is stronger, but they're making the edge weaker in the process. By comparison, on an equal grit stone you cut the teeth instead of standing them up, and end up with a much stronger refined edge that will last drastically longer regardless of what grit you actually sharpen with.
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I cannot agree with anything you have said. Stropping does not make a edge weaker but it can make it sharper and ill bet money my edge off of the stone its waaaaaaaay better than most can do.


When it comes to edge retention grit finished at hardly matters, steel hardness and the sharpened inclusive angle are king. Edge roughness aka what stone you finished on is mostly personal preference.
 
There are so many variables that a blanket statement cannot be made.

Typically people associate stropping reducing edge sharpness/biteyness because they actually round off their apex. Its unfortunate but true. Not to mention that using stropping compound with an unknown mix/type/size of particle can actually have a negative impact on performance even given perfect stropping technique.

So , using a quality product , on a quality strop and using good stropping technique , no there will be no loss of edge biteyness. There just wont.


But to many people all "polished" edges are the same. To the naked eye , theres very little difference between an 8k shapton edge , and a 160k CBN edge. And yet they perform so differently....

On my knives stropping extends edge life. If I touchup without letting the edge degrade beyond what my finishing compound can correct , then you can maintain an edge at whatever finish you want , nearly indefinitely. Typically , once my personal edges see their finishing grit , they don't see a stone ever again until I damage it beyond what I can fix with a compound. Or unless I go back down to change edge geometry or something like that.

8k Shapton edge(doped) , Stropped with 16,000 grit CBN on Roo


160,000 grit edge , also done with CBN on Roo. Yes 10x finer than the edge above....




My poor photography skills aside , visibly (without magnification) there is no difference between these two edges , and yet they are entirely different animals.

And then there is steel type and edge geometry to discuss......
 
j.man said:
I saw this post on http://edcforums.com/threads/toothy-vs-polished-edge.106484/ and was wondering if there is any truth to this?

Also (I'm sure to get lots of disagreement on this one) but stropping is the enemy of edge retention depending on what you're cutting. A barber can get away with stropping a razor because all he cuts is hair, but if you were to take a barber's razor and cut cardboard with it you would destroy the edge. You can get a knife just as sharp with a high grit stone as you can a strop, and get a much more stable and refined edge that will last much longer. If stropping gives you the perception that your edge is getting sharper than when you finished with your stones, then you aren't leaving the stones with a well refined edge to begin with. In other words, your work on the stones needs more work. Strops only bend and stress the teeth on an edge, and so they may stand up those teeth and give you the perception that the edge is stronger, but they're making the edge weaker in the process. By comparison, on an equal grit stone you cut the teeth instead of standing them up, and end up with a much stronger refined edge that will last drastically longer regardless of what grit you actually sharpen with.
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Sorry, but I have to disagree with most of your statements...
The analogy of the barber's straight razor is the same as requesting the use of a Maserati car for off-road mud racing.
The reason the straight razor won't hold up has nothing to do with the stropping. It's using the wrong geometry for the job. Period. Stropping, if done correctly, will improve an edge. If it didn't, it would not have stood up to the test of time. And it has. Period.

But... there is correct stropping and incorrect stropping.
There are people who want to use strops instead of using their stones at the higher grits. It works, but it's not what stropping is for.
Stropping 'should be' the final steps in the sharpening process. If one finds themselves spending 10 minutes stropping, they should have stayed on the stone longer.

A minute or two with a high-grit compound, and 10-20 strokes with a bare strop. THAT is stropping.


Stitchawl
 
I strop all of my edges. And since I started stropping, my knives cut better and the edges last longer.,
 
j.man said:
I saw this post on http://edcforums.com/threads/toothy-vs-polished-edge.106484/ and was wondering if there is any truth to this?

Also (I'm sure to get lots of disagreement on this one) but stropping is the enemy of edge retention depending on what you're cutting. A barber can get away with stropping a razor because all he cuts is hair, but if you were to take a barber's razor and cut cardboard with it you would destroy the edge. You can get a knife just as sharp with a high grit stone as you can a strop, and get a much more stable and refined edge that will last much longer. If stropping gives you the perception that your edge is getting sharper than when you finished with your stones, then you aren't leaving the stones with a well refined edge to begin with. In other words, your work on the stones needs more work. Strops only bend and stress the teeth on an edge, and so they may stand up those teeth and give you the perception that the edge is stronger, but they're making the edge weaker in the process. By comparison, on an equal grit stone you cut the teeth instead of standing them up, and end up with a much stronger refined edge that will last drastically longer regardless of what grit you actually sharpen with.
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Count me among the many who flatly (& respectfully) disagree; especially with the points bolded above (at least).

I can agree, the work done on the stones first is paramount, and will always improve end results when done correctly. But the idea that stropping can't or won't improve an edge beyond that is flatly untrue. This is where choosing the right combination of strop, substrate and compound can not only protect the benefits afforded by the stones, but enhance them. Some poorly-selected stropping combinations of substrate and/or compound can & will ruin or over-polish an otherwise well-performing edge from the stones. Also going too far or too long for the good of the edge. But that's just an individual user-induced issue, and not an inevitable drawback of stropping in general.

Heavy & dirty cardboard, as well as fiberglass, are edge-killers, and the wear induced by such cutting activity is unavoidable. It will often force the issue of re-grinding a new edge regardless of whether a blade gets stropped or not. But again, that's got nothing to do with drawbacks of stropping as a whole. If an edge fails more quickly in such activity, often other considerations like steel choice, edge geometry and making better choices of stropping grit and/or substrate, can still improve the performance of the edge, not being limited only to going back to stones to 'fix' it.

If one is weakening an edge from stropping or, in other words, leaving weakened steel behind, then the stropping isn't being done correctly. Stropping in it's purest form is designed to remove the weakened steel (wire edges) & burrs from a honed edge. When done correctly, it'll make an otherwise good edge really sing, leaving a crisp apex of strong steel that will be better off for the effort.

I don't say the above lightly; it's how I've been maintaining my edges about 98% of the time, seldomly having to return to stones or other coarser abrasives to get the 'bite' back in my edges. In terms of edge-retention (keeping my working edge working longer) and minimizing how much steel needs to come off each time the edge gets touched up (affecting blade life overall), it's a no-brainer over re-grinding an edge on stones each and every time the edge gets a bit dull.


David
 
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I strop all of my knives. And from experience the edges last longer and the time frame between sharpenings is longer.
 
I stropped a few of knives but took forever to get satisfactory edges, where as in my stones get my knives sharp in less than a few minutes.

I guess its whatever you are good at.
 
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