Troubleshooting request: Edge Pro stropping with diamond emulsions/sprays

[OhioApexing]

Thank you to those who gave me insight on my last thread. It was quite helpful. A bit of background:

I’m currently learning to use an Edge Pro system. The stones used are a run of Shapton Glass, Suehiros, and Edge Pro Diamond Matrix (this probably doesn’t factor in). I also have a series of strops and PCD emulsions/sprays running from 4 micron on Balsa, 2 micron on Kangaroo, and 1 through 0.003 on white nanocloth.

I’m primarily sharpening modern “super steels” with some mid-range stuff thrown in.

The issue is this: I’m having trouble removing the burr at high-grits. Possibly on the stones, definitely on the strops.

Note: I’m really only interested in learning how to remove the burr on stones and strops without increasing the angle or dragging the edge on wood or felt. I know this requires more skill and is probably more time consuming, but I believe this is going to give me the results I want once I get it down. I can currently get great working edges, but I’m looking to push into scary sharpness.

On lower grit stones (100 - ~4k), I can see and feel the burr. My technique for removing the burr here is one light, edge-leading stroke. Sometimes I need a second. Too much pressure or too many strokes and the burr just folds over to the other side. Sometimes it’s a bit of back and forth until I figure out what works. Each stone and each steel is different, but I try to get remove the burr on each stone before moving on.

My problem is with high grits, when the burr becomes so small that I can’t feel a “lip” nor see it under magnification.

I was working with a Spyderco in XHP the other day. After the 6k Shapton Glass, I moved to a 4 micron PCD emulsion on a balsa strop, then the 2 micron on kangaroo, then 1, 0.25, 0.1 on white nanocloth.

After this, I realized I had formed a microbevel, probably from too much pressure. When I say microbevel, I mean MICRO. I could BARELY see it under 200x magnification. I mistook it as being the microconvexity we hope to get from strops. The edge cut at a different angle than the actual secondary bevel.

So I went back to the 4k Shapton Glass and apexed again, removed the burr, finished on the 6k SG, then back to the strops.

I used VERY light, edge-trailing strokes, sweeping from heel to tip.

After the 4-micron balsa and 2-micron kangaroo, it seemed to get sharper and sharper. Almost hair popping. Once I got to the 1-micron on nanocloth, I started struggling to get the edge sharp and keep it there. I occasionally shave tested and sometimes it would be obscenely sharp, other times it would barely shave.

I know that experienced sharpeners can get scary sharp edges at this point. I also know my problem is that I’m not successfully removing the burr.

At the end, the knife was sharp, but only on one side (dragging my finger across the edge) Obviously, a burr is still present on one side, even if I can’t see it.

TL;DR Questions:

• How do you detect the burr at high grits? My fingers are somewhat calloused and I have a hard time feeling that really subtle difference.
• For those of you that strop to remove the burr (without increasing angle) how do you do it? Do you alternate sides with every stroke? How many strokes do you do? How much pressure?
• For those of you that strop with sub-micron compounds for additional sharpness, how do you know when to move on to the next strop? Obviously it isn’t a visual cue.
• For those that use the Edge Pro to strop, do you do so with vertical, 90 degree downstrokes? Or do you go in a sweeping, 45 degree stroke?
• Perhaps most importantly, how do you feel about white nanocloth strops? I get the idea that it allows for the edge to be cut only by the actual compound, but I kinda feel like it rolls my edges due to softness.

Thanks for reading! Have a great holiday.

 

[miso2]

My hunch is that your strops, probably the nanocloth ones, cause edge rounding.

 

[OhioApexing]

My hunch is that your strops, probably the nanocloth ones, cause edge rounding.

I know they certainly did when I used too much pressure. When I went back to them the second time, I went as lightly as I could and I know I didn’t round it, but I still had a burr/wire edge — evidenced by the edge being sharper on one side.

 

[115Italian]

Try removing the bur on the stone with a stropping motion instead of a sharpening motion. Sometimes if the bur is large it does fold back and forth a few times. Just keep at it. Also try to keep the bur small. In the early stages if sharpening. Once you see or feel a tiny bur you’re done. Debur and move on.

At a high grit if no bur is felt or seen under magnification then I personally would assume there is no bur and the edge is apexed.

I dont use that many strops in my finishing stage. I use a coarse and smooth leather strop. Coarse is run dry. I do a few pulls in each side then move to my smooth leather with 1 micron diamond paste to finish.

 

[OhioApexing]

Try removing the bur on the stone with a stropping motion instead of a sharpening motion.

At a high grit if no bur is felt or seen under magnification then I personally would assume there is no bur and the edge is apexed.

By “stropping motion” do you mean a veritcal pull-stroke? Instead of sweeping?

At low grits, I can physically feel the burr on one side with my finger when going from the top to the bottom of the edge — it’s the “lip” I’m talking about.

At high grits, I don’t feel that lip. Especially in stropping, I notice that one side “grabs” my finger when dragging it across the edge, but not the other. And it will shave really well on one side but not the other. I’ve read that is indicative of a burr still being present and is folded to that sharp side, even if I can’t feel the lip — it’s too small to detect when dragging my finger top to bottom.

 

[Diemaker]

With a 2.5 micron diamond loaded leather strop I found the most I can do is 2-3 passes before the apex starts getting rounded, with no pressure on the strop when using it. A few more passes and it still shaves but you have to increase the angle to do it. In my experience a diamond loaded leather strop is only for edge refinement, if you can see it doing anything you have gone too far.

It sounds to me that your burrs are bigger than I would expect. What shape are your stones in? Do they need to be dressed? Not saying they do, just food for thought. I like the Shapton Glass stones but have only used them on "softer" steels, say good 440c and lower. I never really had burr trouble but they also didn't have much use since being dressed.

What Matrix stones do you have? I have a bit more experience with these and know they should not raise enough of a burr to worry about, at least with the finer grits. And yes, the stones make a huge difference in our advice.

Do you have any leather strops without compound on them? I prefer the motion of my stones or strops to be nearly perpendicular to the apex, almost always in an edge trailing stroke especially with diamond stones.

 

[miso2]

Can you run the edge on a hard wood block very lightly after each stone and test the edge using sunlight reflection and paper cutting?
Alternatively, you can firmly press your edge on hard wood to fold a burr, if any.

If edge rounding is not the issue here, it might be a lingering wire edge, which can be very sharp and hard to be removed on strops.
Above methods would test if it is the case.

Come to think of it, are you sharpening CPM-SxxV steels?