Too much stropping?

[bpeezer]

I have seen people say that an edge may be "over stropped", and I even read that "stropping too much will end up making the edge dull again." How much stropping does it take to get to the point that you are dulling your edge? I'm not talking about diminishing returns or time efficiency. I did a little experiment to test it, and I didn't find a point where stropping dulled my knife. I did a thousand passes on the strop and still didn't dull the edge. I stopped periodically to test the edge, and every time it would still shave easily and whittle hair.

What am I missing?

 

[Sadden]

Your not missing anything. Its a myth caused by poor technique , strop , compound or a combination of all three.

All this means is that your doing something right

 

[HeavyHanded]

I have seen people say that an edge may be "over stropped", and I even read that "stropping too much will end up making the edge dull again." How much stropping does it take to get to the point that you are dulling your edge? I'm not talking about diminishing returns or time efficiency. I did a little experiment to test it, and I didn't find a point where stropping dulled my knife. I did a thousand passes on the strop and still didn't dull the edge. I stopped periodically to test the edge, and every time it would still shave easily and whittle hair.

What am I missing?

Check for three finger sticky, or use a variety of cut tests to see how the character is changing. In my experience, it takes a very hard strop surface to leave an edge with unchanged character or some micro rounding at the apex, especially on a V bevel. Any deflection into the surface will cause pressure/abrasive spiking at the apex - will remove more material from the apex than the bevel approaching it. Also tends to completely eliminate edge irregularities, but that would only be an issue at finish levels of approx 6k and under. The harder the backing the less of this you will see, right up to lapping on hardwood or backhoning on a waterstone, which leave the apex/bevel more or less completely flat.

 

[neeman]

To check

So the harder the backing the less pressure on the apex
And the less rounding and loss of an edge?
Correct?

And what role does the type of compound perform in this, black, green and white?

 

[HeavyHanded]

To check

So the harder the backing the less pressure on the apex
And the less rounding and loss of an edge?
Correct?

And what role does the type of compound perform in this, black, green and white?

That's about it, much of it comes down to amount of deflection and how well the abrasive is adhered to its base. The harder the backing, the more the pressure is spread over the entire contact surface. The harder the backing, the less the surface will compress, the less it will expand to its previous volume as the apex passes over. If the base is soft(er), the apex will wear faster than the back bevel. As it wears down, you can either elevate the spine or press harder, which will keep it abrading the apex but round the edge. Or you can maintain pressure and pitch, in which case an increasing amount of the abrasion process will fall on the back bevel and less and less will fall on the apex. At some point there will be virtually no action on the apex as its share of pressure drops away.

Convex or Scandi grinds manage to tame this to some extent as the surface will expand to it full volume over a larger area - less pressure spiking at the apex, pressure spread over a larger area, starts out with less pressure on the apex.

You could make an argument that larger abrasives (black) create less edge rounding (all else being equal) and is probably correct. Am not sure how this would be described - maybe surface deflection relative to abrasive particle size? The larger the particle the less resistive force exerted by the flexible substrate? Bluntcut had a theory related to how the abrasives stack, creating a second, more firm surface over the top of the substrate. There might be something to that, or maybe how they pack in shoulder to shoulder, maybe both?

 

[bpeezer]

Your not missing anything. Its a myth caused by poor technique , strop , compound or a combination of all three.

All this means is that your doing something right

That's certainly good to hear

Check for three finger sticky, or use a variety of cut tests to see how the character is changing. In my experience, it takes a very hard strop surface to leave an edge with unchanged character or some micro rounding at the apex, especially on a V bevel. Any deflection into the surface will cause pressure/abrasive spiking at the apex - will remove more material from the apex than the bevel approaching it. Also tends to completely eliminate edge irregularities, but that would only be an issue at finish levels of approx 6k and under. The harder the backing the less of this you will see, right up to lapping on hardwood or backhoning on a waterstone, which leave the apex/bevel more or less completely flat.

That was the interesting part. Three finger sticky didn't leave or stay entirely, it would go through cycles. I have trouble quantifying it, so I wasn't sure if I should mention that. Cutting thin paper had very small changes in the sound it made. This also went through cycles.

My edges normally hang out around HHT-2, splitting/whittling hairs. I have to focus and be very careful to get it sharper than that, so normally I just live with it. At two different points I got a clean HHT-4, which was very surprising to me.

I may have to try the same experiment with loaded paper on the washboard to see if I get different results with a harder surface with more feedback.

 

[HeavyHanded]

That was the interesting part. Three finger sticky didn't leave or stay entirely, it would go through cycles. I have trouble quantifying it, so I wasn't sure if I should mention that. Cutting thin paper had very small changes in the sound it made. This also went through cycles.

My edges normally hang out around HHT-2, splitting/whittling hairs. I have to focus and be very careful to get it sharper than that, so normally I just live with it. At two different points I got a clean HHT-4, which was very surprising to me.

I may have to try the same experiment with loaded paper on the washboard to see if I get different results with a harder surface with more feedback.

A big part of this might come back to inclusive angle as well, the more acute the better. On hard enough leather you may very well be missing nothing - edge will stay mighty crisp with a broad, acute bevel, light touch, hard leather strop.

On the Washboard you have some more factors coming into play. I'd use two sheets of paper, compressed on the board with a rag. There will be a noticeable difference as you change the rake angle across the board - if the edge is parallel to the relief cuts you'll get more of a microtoothy tree-topping edge. As the rake angle becomes closer to perpendicular to the relief cuts, feedback will diminish and the abrasive will work a lot less aggressively - more polish. This is how I work when gunning for a whittling edge. After that its going to be burnish on plain paper in the same fashion with light to moderate pressure with a slight elevation of the spine. WB wasn't made for HHT-4, but I have chopped some neatly in half coming off it - treetopping is more the norm, and with care whittling. Biggest difference is the WB can get there from a fairly unrefined edge (600 grit sandpaper).

Sounds like you have some Noodling to do...

Martin

 

[HeavyHanded]

One last thought to make sure we're on the same page - are you stropping on leather with an abrasive, or just the plain leather?

Changes everything - you could strop on plain leather for a loong time and probably see no definitive change. Adding an abrasive to the surface is whole different ball of wax.

Martin

 

[neeman]

Martin

Thanks

 

[Sadden]

I would sugest that the variance in edge performance would be coming from variance in your technique. 1000 is a lot of strokes. Even.by my standards.

Even a lttle variaince can make a big impact on how an edge performs , whats going on at the edge of the edge is what really matters , just looking ay the bevel you wont.be able.to see a difference.

Take my sig for example. Yeah thats a pretty bevel , but thats not what matters. Look at the edge of the edge , thats the impressive part. Thats at 400x .... Scratches on the bevel cangive you clues as to whats happening at the edge of the edge , but the physical edge tells the real story.

 

[bpeezer]

One last thought to make sure we're on the same page - are you stropping on leather with an abrasive, or just the plain leather?

Changes everything - you could strop on plain leather for a loong time and probably see no definitive change. Adding an abrasive to the surface is whole different ball of wax.

Martin

Sorry I didn't specify, I am using abrasive. I've actually never stropped with plain leather, it's on my list along with a million other things Here is the compound I use, definitely let me know if you think I should switch to something else.

I would sugest that the variance in edge performance would be coming from variance in your technique. 1000 is a lot of strokes. Even.by my standards.

Even a lttle variaince can make a big impact on how an edge performs , whats going on at the edge of the edge is what really matters , just looking ay the bevel you wont.be able.to see a difference.

Take my sig for example. Yeah thats a pretty bevel , but thats not what matters. Look at the edge of the edge , thats the impressive part. Thats at 400x .... Scratches on the bevel cangive you clues as to whats happening at the edge of the edge , but the physical edge tells the real story.

I figured that was most likely the case, I wasn't really concentrating (it got a little repetitive) so I felt like the variation was probably my fault. Also, I did check the edge under the Veho every 50 or 100 passes. The very edge got cleaned up pretty quickly, and after that it mostly looked like the very edge was staying fairly similar while the scratch pattern got more and more refined.

On the subject of the microscope, do you have a rigid setup to hold yours? I have trouble getting good pictures with mine, and I would like to build something to hold it a little better.

For an example, here is an edge after the 400 grit stone. I gave it 5 passes on the strop with almost zero pressure just to clean up the edge, so you can see it still has some rough spots.

I got some good pictures of the edge last night, but I didn't save them and they're gone now I'll see if I can get another one.

 

[HeavyHanded]

Sorry I didn't specify, I am using abrasive. I've actually never stropped with plain leather, it's on my list along with a million other things Here is the compound I use, definitely let me know if you think I should switch to something else.

I figured that was most likely the case, I wasn't really concentrating (it got a little repetitive) so I felt like the variation was probably my fault. Also, I did check the edge under the Veho every 50 or 100 passes. The very edge got cleaned up pretty quickly, and after that it mostly looked like the very edge was staying fairly similar while the scratch pattern got more and more refined.

On the subject of the microscope, do you have a rigid setup to hold yours? I have trouble getting good pictures with mine, and I would like to build something to hold it a little better.

For an example, here is an edge after the 400 grit stone. I gave it 5 passes on the strop with almost zero pressure just to clean up the edge, so you can see it still has some rough spots.

I got some good pictures of the edge last night, but I didn't save them and they're gone now I'll see if I can get another one.

That's pretty good CrO, is what I use for a green compound. Have used it on the Washboard and it works pretty well.

For the microscope, I use a chunk of rigid styrofoam. Just stab into the block at the best angle for viewing, and if necessary elevate one side or the other with a small wedge.

After repeated passes doesn't the leather load up?

 

[bpeezer]

That's pretty good CrO, is what I use for a green compound. Have used it on the Washboard and it works pretty well.

For the microscope, I use a chunk of rigid styrofoam. Just stab into the block at the best angle for viewing, and if necessary elevate one side or the other with a small wedge.

After repeated passes doesn't the leather load up?

Yeah, I had to clean my strop more than once during the process :barf: I let my strop get pretty dirty between cleanings though. I usually wait until the surface starts to tug at my blade, that's when I can see it starting to burnish if I check under the scope. At least that's what I think I'm seeing. I rely more on the feedback than the scope, because I don't exactly know what I'm looking for at that point

 

[VClaw]

Different steels/grinds definitely behave differently based on pressure in my experience. I think it comes down to muscle memory and trial and error for each blade on how they are stropped.


I can't wait to get a proper tool to magnify my view of the edge. I really think that's what's going to take my edges to the next level. Being able to really check the edge every 10-15 passes and see what's happening at that level of detail.

 

[bpeezer]

Different steels/grinds definitely behave differently based on pressure in my experience. I think it comes down to muscle memory and trial and error for each blade on how they are stropped.


I can't wait to get a proper tool to magnify my view of the edge. I really think that's what's going to take my edges to the next level. Being able to really check the edge every 10-15 passes and see what's happening at that level of detail.

I agree, pressure can make a huge difference. And as for magnification, I suggest a Veho microscope. Pretty cheap, and up to 400x magnification.

 

[VClaw]

I agree, pressure can make a huge difference. And as for magnification, I suggest a Veho microscope. Pretty cheap, and up to 400x magnification.

Thanks just did a search. Looks like 5oish bucks on average for 400x. Worth it? Seems like the max before some huge price jumps. I mean can I see my strops with a 400x? Or should I save for something better?

 

[bpeezer]

Thanks just did a search. Looks like 5oish bucks on average for 400x. Worth it? Seems like the max before some huge price jumps. I mean can I see my strops with a 400x? Or should I save for something better?

Definitely worth it in my opinion. If I wanted something better than that, I would probably look at the amscope 40x-1000x with the USB imager for about twice the price. It's not a purpose built USB scope, but rather a glass optic microscope with a USB camera attachment that can go on the eye piece. I have absolutely zero experience with that though, so I can't really recommend it

 

[HeavyHanded]

Definitely worth it in my opinion. If I wanted something better than that, I would probably look at the amscope 40x-1000x with the USB imager for about twice the price. It's not a purpose built USB scope, but rather a glass optic microscope with a USB camera attachment that can go on the eye piece. I have absolutely zero experience with that though, so I can't really recommend it

At work we have the AmScope 40x-1600x with a 5 megapixel USB camera - is what I use for posting edge pics. Was about $900.00, so there's no way I'd buy one for myself. I have to say though, it gets some very clear shots. Is amazing what can be seen at 1000x + that is all but invisible at 400-640. At 1000x using oil immersion, I have to hang a sheet of paper between myself and the stage or my exhalations, no matter how slight, cause the image to shift in and out of focus.

 

[bpeezer]

At work we have the AmScope 40x-1600x with a 5 megapixel USB camera - is what I use for posting edge pics. Was about $900.00, so there's no way I'd buy one for myself. I have to say though, it gets some very clear shots. Is amazing what can be seen at 1000x + that is all but invisible at 400-640. At 1000x using oil immersion, I have to hang a sheet of paper between myself and the stage or my exhalations, no matter how slight, cause the image to shift in and out of focus.

That's awesome, I had no idea it would be that sensitive. The one I was looking at goes to 1000x and it costs around $125. It only uses a 2 megapixel camera though so image quality wouldn't be the same. I'm still considering it though, I would get more use out of it than another knife

 

[HeavyHanded]

That's awesome, I had no idea it would be that sensitive. The one I was looking at goes to 1000x and it costs around $125. It only uses a 2 megapixel camera though so image quality wouldn't be the same. I'm still considering it though, I would get more use out of it than another knife

For $125 it would be worth it. Between backlighting the edge and figuring out what your depth of field is, you can get a real good idea how crisp your apex is. I imagine even the 400x images off the AmScope would be far more informative than the Veho. Not sure about the 2 megapixel, but in all reality is probably plenty good enough - its what you see through the eyepieces that's most important anyway, though always fun to share!