Effects of stropping on coarse edge.

[Nosetotail]

As some who have been quite helpful to me know I have been trying to iron out a possible sharpening issue I have been having with my ZDP blade. I'm having some issue cutting nylon "mule tape" without raising a burr or flat spot on my edge. In an effort to eliminate a possible wire edge, I have been experimenting with some light stropping. I have tried several times on the leg of my jeans, but I don't seem to get any noticeable results, so I broke out the leather strap I bought and took about ten to fifteen alternating slow light strokes. I did this on an unloaded portion of the nappy side. I raised the blade up just to when I could hear the edge scraping the leather. This put a much more effective shaving edge on an edge sharpened nominally shaving sharp with an ex coarse dmt stone.

So my question is concerning the "toothy edge" that I was trying to aquire. Does stropping with unloaded leather smooth out the micro serrations or just knock the burrs away from them leaving cleaned serrations? On that note, if I am just trying to knock any burrs down, without polishing my edge, should I raise my angle even more and take less strokes, or should I stick with about ten or fifteen light strokes with the lowest effective angle?

I am wondering if I am even on the right path stropping with unloaded leather to finish a "toothy" edge. I am having some success with the strop, but am afraid that I may be creating a less effective edge for the nylon flat strap as the toothy edge seems to eat through it the best.

 

[65535]

My advice would be to finish the edge at 1200 grit on a stone if you are good at it, don't even bother with a strop they are made for polishing compounds to produce a polished edge.

 

[Cliff Stamp]

My advice would be to finish the edge at 1200 grit on a stone if you are good at it, don't even bother with a strop they are made for polishing compounds to produce a polished edge.

The stone would remove the coarse edge completely.

In an effort to eliminate a possible wire edge...

Do that on the stone.

So my question is concerning the "toothy edge" that I was trying to aquire. Does stropping with unloaded leather smooth out the micro serrations or just knock the burrs away from them leaving cleaned serrations?

It will mainly be deformation based. Use the stone properly and minimize the burr there.

-Cliff

 

[Nosetotail]

The stone would remove the coarse edge completely.



Do that on the stone.




It will mainly be deformation based. Use the stone properly and minimize the burr there.

-Cliff

Well I am very careful when I finish with my stone, almost to the point of excess. It is one of my longest steps. I'm just trying to eliminate the possibility that I may be leaving something weak. This percieved if not imagined problem is due to what my edge feels like after about twenty cuts through the strap. Perhaps it is normal. The more I inspect it, the more I think this "burr" that the strap leaves actually runs on both sides of the edge, and may be like a micro flattening caused by having to apply hard pressure against the nylon on my last several cuts.

Nonetheless, I tried cutting with the lightly stropped edge and it performed quite well, but ultimately produced the same flattened edge.

I appreciate you comments, as that gives me confidence that I have been on the right track eliminating the burr with my stone.

 

[Habeas Corpus]

I usually eliminate a burr by drawing the edge about 10 times across my fine ceramic stone. This is done edge trailing, and I only use very light strokes at my usual sharpening angle. The idea is to raise a tiny burr.

I then turn the knife over, raise the angle to at least twice my sharpening angle and do one very light stroke on the stone, this time with the edge leading. This stroke seems to remove the burr completely, resulting in a clean edge.

Works pretty well for me, even with hard steels such as ZDP-189.

Hans

 

[hardheart]

a toothy edge would have teeth, no? if you are applying a lot of force, those teeth are fairly small, making for really high pressure. the teeth break off, and you're left with flat spots where they used to be.

I wonder how unloaded leather helps an edge. It's nowhere near as hard as even the softest steel edge, so how it is able to refine an edge confuses me. Sort of how a smooth steel is supposed to be harder than the knife to align the edge, yet you can damage your edge on soft metal, or clean it up on an old belt.

 

[Nosetotail]

Well I'm not sure what is happening at the edge, however I know it does something. My ex coarse edge will only remove a few coarse hairs on a single swipe before stropping and after about ten light strokes on the unloaded strop, it will shave a bare spot. I still have to raise the angle and apply a little pressure, but it certainly shaves a bare spot. It is the kinda edge that you have to push into the hair to shave, but still much more effective than the original coarse edge.

 

[Cliff Stamp]

I wonder how unloaded leather helps an edge. It's nowhere near as hard as even the softest steel edge, so how it is able to refine an edge confuses me.

The edge of a knife is quite thin and thus the lateral strength is lower than the compressional strength of the leather.

-Cliff

 

[hardheart]

would that mean napped leather is less effective, and what about the idea that there are silicates in the leather removing steel? I wonder exactly how it effects the edge for something like zdp189.

 

[db]

I’m not real sure I understand what is happening to your edge, burr on both sides? Maybe you are grinding too thin for the type of cutting your doing. Try just grinding off the burr that is left after cutting the strap with your hone instead of regrinding the edge. This will give you a stronger thicker angle mini edge. It should only take a very few strokes at a higher angle. Alternate after each stroke. 1 left side 1 right side, repete if necessary.
As for stropping a coarse edge. If you just do 1 or 2 per side it will clean up the edge and teeth. If you do much more than that you are starting to polish the edge and lose some of the coarseness.

 

[Jeff Clark]

I would sharpen your blade up to the finest grit that you have available, using edge-forwards strokes for the later steps. Then I would debur the edge using a few light edge-forwards strokes at about 30 degrees per side. At his point you have no burr, but you also only have a smooth edge. Now you create a coarse edge finish using a minimal number of light edge-forwards stokes on your DMT hone. This should not create a burr, just give you microserrations. I would do this at around 25 degrees per side to provide some extra edge strength. A little light stropping with your unloaded leather strop should just make your microserrations more distinct.

Your nylon tape is hard to cut without folding over the edge. A smooth edge is tougher than a coarse edge. Your rough finish will cut better, but the microserrations will tend to flatten out fast on that tough nylon. You might be better off if you created a convex edge for this purpose. Strop your edge on a sheet of 600 grit Wet or Dry paper lying on a pad of paper. This will give you some microserrations, but will also give you a more stable convex edge profile. The convex edge will resist folding over better than most styles.

 

[Nosetotail]

I’m not real sure I understand what is happening to your edge, burr on both sides? Maybe you are grinding too thin for the type of cutting your doing. Try just grinding off the burr that is left after cutting the strap with your hone instead of regrinding the edge. This will give you a stronger thicker angle mini edge. It should only take a very few strokes at a higher angle. Alternate after each stroke. 1 left side 1 right side, repete if necessary.
As for stropping a coarse edge. If you just do 1 or 2 per side it will clean up the edge and teeth. If you do much more than that you are starting to polish the edge and lose some of the coarseness.

I'm not sure what to call it. It feels like a burr when I rub with my fingernail across it, and perhaps it is just alternating sides. It is after I make several cuts with the strap and I get to a point that I am having to bear down with some force to get through the strap in one or two slices. The last test I did was with the lightly stropped edge and I got to about thirty or thirty five slices before I decided I should quit, and the burr was there. I quit when I consistently had to make two slices to complete a cut. This is a marked improvement from about twenty slices, so I think I am satisfied with the performance, but I am just perplexed by the raised spots running down my edge.

I tried something similar to what you described. I stropped with a little more force and about five more degress of angle till I couln't feel the "burr" on either side. This just resulted in a dull edge. I'm certain that it was just a rounded edge, and that I would get better results if I did it with a stone, however I am a little leary that I would be creating a bit more work for my self to get back to my original angle which is about 33 to 35 degrees.

 

[db]

Yup stropping with more force and raiseing the angle wil round off the edge. Give the stone a try. Check after each stroke and stop as soon as the burrs are gone, that way you don't have to worry about effecting your 35 ish degree bevel. I'd sstrongly suggest rereading Jeffs post also. I'm kind of biased though I really favor a convex edge.

 

[Cliff Stamp]

...what about the idea that there are silicates in the leather removing steel?

Verhoeven has shown that has minimal if any effect.

Now you create a coarse edge finish using a minimal number of light edge-forwards stokes on your DMT hone.

Jeff do you feel it is necessary to polish and then back finish rough in order to create minimal burr with a coarse edge.

It is after I make several cuts with the strap and I get to a point that I am having to bear down with some force to get through the strap in one or two slices.

It is normal all edges will dull, it is also expected that they can dull by side biasing like you noted depending on how you cut. You can notice this especially if you whittle wood or similar which puts more force on one side of the blade only. I would suggest looking at the angle to make sure it is at the optimal level both by going under and as well as increasing it. When you increase it you have to decrease the grit to get the same level of slicing aggression.

-Cliff

 

[Nosetotail]

I can understand the concept of a convex edge being more stable, however I have just begun to try stropping. I was under the impression that stropping for a convex edge was a little more advanced. Is this the same as stropping with a mouse pad underneath?

If I am going to try it, should I use exactly the same angle as my primary bevel or should I go up or down a few degrees? I'm not sure about trying on a backed surface freehand, but I think I can strop using my aligner. It worked superbly rebevelling on a stone. How much force and how many strokes should I strop with?

Sorry for the deluge, I can't get anything to come up on my screen with the search function at this time.

 

[Jeff Clark]

Use light pressure and/or a stiff pad when you strop. If you press into the pad material appreciably it will wrap around the apex of your edge and make it excessively obtuse. I would shape your edge contour using flat hones at your normal angle (a somewhat low angle). Stropping will make the apex of the edge somewhat more obtuse than your flat honing angles. If you use a stiff stropping pad the increased angle will be minor.

 

[Greg]

If you are talking about the DMT Aligner then you can make a very good strop by gluing a very thin bit of leather on the back of your least used hone (I just cut a bit of plywood to the size of the hone), load it up with some polishing compound and then finish the sharpening with a series of LIGHT strokes. Make sure you use the leather from the back of the blade towards the edge.
Greg

 

[Nosetotail]

Use light pressure and/or a stiff pad when you strop. If you press into the pad material appreciably it will wrap around the apex of your edge and make it excessively obtuse. I would shape your edge contour using flat hones at your normal angle (a somewhat low angle). Stropping will make the apex of the edge somewhat more obtuse than your flat honing angles. If you use a stiff stropping pad the increased angle will be minor.

Sorry about the lack of response, I have to lay off a day or two sometimes.

What I am getting from your post here is that in order to protect my self from rounding the edge I can go with the stiffer backing, but this leads me to wonder if a more flexible backing is used purposely according to the type of convex edge someone is trying to attain. I'm imagining an even lower angle that is offset by a more drastic obtuse. Am I getting the idea here?

 

[Nosetotail]

If you are talking about the DMT Aligner then you can make a very good strop by gluing a very thin bit of leather on the back of your least used hone (I just cut a bit of plywood to the size of the hone), load it up with some polishing compound and then finish the sharpening with a series of LIGHT strokes. Make sure you use the leather from the back of the blade towards the edge.
Greg

And I thought I was a genious. I've had my kit for about three years and I just placed an order for a replacement kit to get the new stones. I had planned on trying a shammy type piece of leather on my old stones with a couple of different compounds. I am also in the process of looking for some H or T shaped angle aluminum that is about one inch wide and about one or two inches in height and about 3/16" thick. If I can find a piece about three to six feet long, I can make a half a dozen hones with varying high grit paper or just paper to hold some diamond paste. I figured plane old two sided tape would be great for quick removal of used polishing paper. I'm also thinking about trying plane old dry compound right on the tape.