New to stropping, should it take so long?

S

shadowspawn

Joined
Jul 12, 2011
Messages
44
I sharpen my knives almost exclusively on a King 1000/4000 water stone and have been deburring by simply drawing my knives through a piece of wood up until recently. Just picked up this cheap piece of leather with honing compounds for cheap on Amazon and have been using it to deburr my knives. I also picked up a 30x jewelers loupe to inpsect the wire edge as I'm stropping and it seems to be taking a considerable number of passes to get the wire edge to vanish assuming I'm looking at the right thing. I'd say I spend about as much time stropping as I do actually apexing the knife. Is this normal and if it is, why is this method of deburring so popular when much quicker methods of deburring that produce an adequate end result exist such as drawing the edge through wood?
 
Stropping should never take more than a minute or so, or even down to 3 - 5 passes per side, total.

Something's not right. Either there's actually no burr, or the compound used isn't working at all. What compound is it?

Most importantly, how's the edge cutting? I don't like relying solely on visual checks for the presence of burrs. If you're looking for reflected light from the apex, a tiny microbevel or a rounded apex can reflect light in the same manner. If the edge isn't cutting paper at all, for example, I'd bet the edge isn't fully apexed, or it's rounded off. If it cuts paper somewhat, but snags and/or slips while doing so, there may be a partial burr or a folded burr. But again, if stropping isn't changing (improving) that behavior, the edge likely wasn't fully apexed in the first place. Best approach is to test cutting coming straight off the stone, before stropping at all, and then see if cutting improves with stropping. If stropping isn't changing or improving it, the edge likely needs more refinement on the stone first, to a full apex.

Another possibility might be if the burr is extremely thick & heavy. If so, it should be very easy to feel with your fingertip or nail. If the burr's that heavy, it's an indication pressure is much too heavy in the finishing strokes on the stone, causing the edge to effectively 'roll' over in the same manner a burr would, but much too early with the heavy pressure. If the compound isn't very aggressive for the steel, a very heavy burr may not respond to stropping.
 
It depends on the steel, edge profile and how aggressive the abrasive is. I've seen it take that long. But coming off a water stone your edge shouldn't have much of a burr. With your loupe are you seeing little sparkles like glitter? DM
 
Last edited:
what happens if you just strop on the back of a leather belt with no compound ?
 
It cuts paper fine. I use newsprint as my test medium and it slices that up no problem. As per testing right off the stone, I've been doing that for a while and simply pulling the knife through wood when the cut is to my satisfaction. The knife isn't "treetopping sharp", but it's sharp enough for me to take my sideburns off with no irritation. Cutting did improve after stropping, but only after several passes. Then again, I wasn't testing while stropping and simply using the loupe to inspect the edge as I stropped.

As per steel, edge profile, and compound, it's M390 with a slightly convex edge (as mentioned, I exclusively use stones for sharpening and grinding) and the compound is "green compound" which I assumed was CrOx. It is possible that it's some other "green compound" that's even less aggressive than CrOx if such a thing exists.

As per what happens when I strop without compound, I haven't tried it, but I don't imagine it would deburr any quicker than with compound. I'd have to run it over my stone again to test this out at a later date.
 
I'd skip the green compound entirely, for that steel. Green (chromium oxide) works well with simple carbon & low-alloy stainless (420HC, etc), but won't add much refinement to more wear-resistant steels like M390 or anything else with much carbide content. Both chromium carbide and vanadium carbide are harder than CrOx compound, by a pretty significant margin. Diamond/cbn will work much better for those carbides, especially if vanadium content is ~ 3% or more (M390 has 4% vanadium, not to mention it's chromium at 20% as well).

The lack of progress or refinement you're seeing, with leather and green compound on M390, is exactly the same behavior I first saw years ago, in using green compound on leather while stropping S30V (4% vanadium). The longer I went, the more burnished & rounded the apex became. Green just doesn't work well with steels like these.
 
Last edited:
I think stropping can be a good technique for deburring, but only in moderation. Something less than 10 passes per side is the right amount for most blades I've worked on.

This is because stropping on leather really isn't all that good for removing a big burr. It's really only good for removing the last hangers on of the burr. The little pieces that remain after using the stone or other methods (like drawing through wood) to deburr.

It's possible that your stropping angle is really low and you aren't really touching the apex, except when your hand wobbles a bit and lets the apex touch. It's also possible that you're massively over stropping and perhaps rounding the edge a bit in the process.

Here's one way to determine a good stropping angle:

Lay the blade flat against the strop and begin moving it *edge forward* into the strop. Raise the blade as you go. Do this slowly. At some point, the blade will start to "catch" on the strop. Stop. Lower your angle *just* a hair. That's your stropping angle.

Good luck.

Brian.
 
You might want to try some different compound on a new strop. Chromium oxide isn't a very hard abrasive and m390 is a powdered super steel with carbides and often 60+hrc.
 
I cant add much to Daves post, the Man knows his stuff. Loung La taught me less is more with stropping.
He gave me some quality .25mic diamond paste that worked great, just a couple light passes on each side and it was a marked improvement. A few more strokes, more is better, right? Nope, you got a wire edge, and it didnt take more than a few too many to screw your work up..
Work on the sharpening, read on stropping and go easy
There are some new "experts" on here talking about stropping through a full episode of " american ninja''.
That is just too much. Many dont strop at all and they remove burrs just fine thank you. Listen to what Dave said, I predict you get a lot of questionable info in this thread.
 
shadowspawn said:
I sharpen my knives almost exclusively on a King 1000/4000 water stone and have been deburring by simply drawing my knives through a piece of wood up until recently. Just picked up this cheap piece of leather with honing compounds for cheap on Amazon and have been using it to deburr my knives. I also picked up a 30x jewelers loupe to inpsect the wire edge as I'm stropping and it seems to be taking a considerable number of passes to get the wire edge to vanish assuming I'm looking at the right thing. I'd say I spend about as much time stropping as I do actually apexing the knife. Is this normal and if it is, why is this method of deburring so popular when much quicker methods of deburring that produce an adequate end result exist such as drawing the edge through wood?
Click to expand...

So, I have done a lot of work with the cheaper abrasives to see just how much work you can squeeze out of them, in the name of cost-efficiency. You definitely can succeed with King stones and CrOx and M390. Just last night, I got my MT26 in freakin' PM A11 to hair-whittling with nothing more than the King 1200, King 6k, and and green compound on MDF.

It's a game of patience though, and diamonds will get the party poppin' way faster. But the point is: it's possible with the tools you have already. I make no delusional claims of its time-efficiency. Better abrasives work better, and diamonds are simply better, but you also don't need to run out and drop $400 on a new diamond plate setup to get the sharpness you want.

That being said, though, the deburring on leather part shouldn't take long. I minimize my burrs a lot on the stones, which I believe is paramount for achieving maximum sharpness. I want there to be as little work as possible for the final stropping step. Stropping for my process takes about 30 to 60 seconds. Burr minimization is so easy to do, such a fast process, and it makes achieving maximum sharpness so much easier that I think it is a mistake not to do it.

My procedure is this:
- Draw burr on side A
- Draw burr on side B
- Flip back and forth a couple times, using feather-light strokes to minimize the burr.
- Use a couple gentle high-angle (edge angle + ~5dps) stropping passes on my finishing stone only to set my apex
- Bare leather, lightly, maybe 10-ish passes per side to clean up whatever minute burr was formed with my high-angle work

Final note: diamonds aren't expensive either, so there is no reason not to buy some pastes. I don't recommend Norton or DMT pastes simply because they are absurdly expensive. Jeweler's polish (assorted diamond pastes) are available on places like Amazon or Ebay for super cheap, and I have found several random brands to work fantastically.
 
Last edited:
I've only ever heard of ferric oxide, chromium oxide, and diamond spray for polishing compounds. Where would I get chromium carbide and vanadium carbide? I had a feeling it was just that green wasn't hard enough to pull the wire edge off completely. Just to confirm though, this is what I'm trying to get rid of
IMG_20180616_104154.jpg
Quality is bad because it was tough balancing the loupe and my phone at the same time to take the picture.

As per stropping vs pulling through wood, I was under the impression that pulling the edge through wood basically "ripped" the wire edge off and left a deburred, but jagged edge which is why the method isn't even considered for straight razors? I figured it was a method that was "good enough" if you don't have time to strop your knife on leather and that in order to get the full benefits from stropping, you need to go straight from stone to strop. Also would cuts in the leather from the edge "catching" affect the stropping ability at all? I ask because I already have a couple small ones that I can only imagine came from turning too much and letting the tip touch the strop.

As per diamonds, I have a diamond plate that I use for lapping that I picked up for like $10 on Amazon (or at least what the seller advertised as a diamond plate). They're rather coarse though at 220/400 grit on each side, but I bought it primarily for lapping and potentially grinding in the event of a very bad chip. What kept me away from diamond compound is the stories I heard about how easy it is to overapply the compound and ruin the strop. I was really just looking for a cheap kit to get started and this particular setup came with the presumed CrOx included as a bonus so I took it. Here's a link to the thing I bought for reference https://www.amazon.com/dp/B07214VMGB/ref=twister_B07DKCC594?_encoding=UTF8&th=1

Finally, how important is it that the strop be flat? It doesn't seem to be too important from what I've read so I've just been holding it somewhat flat with my hand on a countertop and stropping across that if it makes any difference.
 
Vanadium is in the knife steel. You have the steel of the knife which comprises of carbides on the micron scale. Your chromium oxide is an abrasive.

I haven't seen any stories of over stropping with diamond compound here at least not recently. It's only really needed for hard steel ie steel that's been heat treated to over 60hrc or steel that has harder carbides inside the steel matrix. Each steel type is comprised of different variations of carbides in it. Check out zknives.com and you can read more up on it and they have a interactive chart that you can compare different steel and see which steel has which components in it and what percentage of each one.

Here's one for just m390
http://www.zknives.com/knives/steels/steelgraph.php?nm=m390

You can see it has about 4% of Vanadium in it. That Vanadium is sprinkled around inside your knife blade among the rest of the stuff. The steel itself is the matrix holding those carbides in. Each brand has different properties due to these different percentages.

Vanadium is a very hard carbide that very few abrasives can cut. You can cut the matrix of steel and the other carbides in the matrix with many different abrasives and make the steel "sharp" but the Vanadium will not be cut but rather pulled out unless using diamonds.
On top of that you have heat treatment of the steel which determines the steel matrices hardness. The harder the steel the harder the abrasives you will need to sharpen it in a timely manor.

Diamond and cbn can sharpen nearly everything. While sic, ceramic, alumina oxide and chromium oxide are less hard. Each one differs on a scale of how hard they are. Iirc your stropping compound is very low on this scale.

Depends on the steel type, and hrc (hardness measured) that you want to pick your abrasives. M390 has 4% Vanadium and gets to between 59 and 62hrc (so very hard).

Diamond would not be idea for soft steel because it would just rip up the steel edges. Also not needed for steel with low amounts of Vanadium.

I can get knives with s90v or s110v (large % of Vanadium) sharp with different abrasives, but they are going to take much longer to do, load up the abrasives and if it's coarse enough stone progression, it will just plow through the matrix and not bother those tiny Vanadium carbides too much. But when going to very high grits and around 1 micron stropping there will be a larger difference. Plus Vanadium is used in knife steel for edge retention... If my Vanadium isn't getting cut its going to reduce edge retention.

In any case stropping can still raise a bur, so it's best to keep it small as possible when sharpening . Also a stubborn burr may be very hard to see and even harder to remove it. Using a stone to remove the burr on these is probably more idea.

This is probably the simplest way to explain it. I would bet someone else could give a much better explanation of it than myself. Also I left out alot of commas and grammar.

Also check out steel http://knifesteelnerds.com
 
Last edited:
Don't be hard on yourself Mo. This is complex stuff and I thought you did just fine.
shadow, try a stropping motion on a x fine diamond stone and see if those glitter spots come off. DM
 
shadowspawn said:
also picked up a 30x jewelers loupe to inpsect the wire edge as I'm stropping and it seems to be taking a considerable number of passes to get the wire edge to vanish assuming I'm looking at the right thing. I'd say I spend about as much time stropping as I do actually apexing the knife.
Click to expand...

Yeeeesssss . . . that's why . . . for one of many reasons I never strop.
If one watches the YouTubes people are talking about . . . 30 strokes per side, 50 strokes per side . . . 100 etc . . .
then . . . they change grits and go to town all over again o_O

Heck I can sharpen a well profiled knife from dead dull to hair whittling and zero bur (assuming high quality steel properly heat treated toward the hard end of the spectrum) . . . in 30 to 60 strokes per side TOTAL on five stones.

Why would I EVER want to strop one ? ! ? !
 
Last edited:
If you want to try a good diamond paste go to ebay and just type in poltava diamond paste and look for stuff in white containers being some from the Ukraine you can 9 1OZ containers for 26 bucks and 12 bucks shipping or you can also buy in smaller lots as well the poltava stuff is good and it has 4 Karat's of diamonds in it and you can also type in high concentration diamond paste that has 10 Karat's in a 1 OZ container.

I use a guided system and I have problems at all making a brand new Ash strops black with metal swarf in no time.

These were all brand new strop's and it took only 2 minutes with each to get them to look like this,also you may want to try MDF Beansandcarrots did a thread where he free hand sharpen's with MDF and say's he can use more pressure and also use push and pull strokes when stropping to make it go faster,he was able to get a S110v steel blade back to hair whittling using MDF and he use's leather for his last step in stropping.

iRZLVTD.jpg


6UJM2dg.jpg
 
I must not have interpreted what was meant when bringing up chromium and vanadium carbide then. I was under the impression they were suggestions for polishing compounds that would cut more aggressively than CrOx but not as aggressively as diamond.

As per vanadium in the knife, so basically what you're saying is that even though the steel itself is rated at 60-62 hrc, technically there are parts within the blade (vanadium carbides) that are much harder and cannot be cut by anything but diamonds. Because of this, there will always be some amount of inconsistency throughout the steel wherever those vanadium carbides are present while using CrOx. As per "pulling" the vanadium from the steel, the way I always envisioned the cutting process of anything was that the individual abrasive particles act as pressure multipliers by exerting an input force over a significantly smaller surface area. So long as the abrasive doesn't deform, it cuts into the material by shearing it at the contact point in much the same way a paper cutter works. With this understanding, I'd imagine that the vanadium carbides would instead fall out on their own accord as the steel infrastructure holding them in place is cut away.

I've heard lots of talk about how diamonds are more edgy abrasives while everything else is more rounded which means it will, by nature, cut much more aggressively than other compounds since the surface area that is making contact with the edge is much smaller per particle size. With this being said, it seems like it would make more sense to get a ridiculously fine stone/plate and just use that to strop if diamonds are the only things hard enough to cut the vanadium carbides. In this case, it would seem that Wowbagger shares my mentality that it doesn't make any sense to use a dedicated strop for extra hard steels since the difference they would make is negligible at best.
 
Part of it is de-burring the edge to also help the edge to last longer and that's what I have found,also I know guys that sharpen by hand like you do but also have an edge pro and use it with strop's and diamond paste only to bring back the edge and if you use something like MDF or as I have just found out Ash it does not take long at all to restore the edge with diamond paste and if it's a good quality one,if the edge is not damaged you can just strop the edge back a few times I have heard some guys say they can do it 3 to 4 times before needing to use stones.
 
shadowspawn said:
I must not have interpreted what was meant when bringing up chromium and vanadium carbide then. I was under the impression they were suggestions for polishing compounds that would cut more aggressively than CrOx but not as aggressively as diamond.

As per vanadium in the knife, so basically what you're saying is that even though the steel itself is rated at 60-62 hrc, technically there are parts within the blade (vanadium carbides) that are much harder and cannot be cut by anything but diamonds. Because of this, there will always be some amount of inconsistency throughout the steel wherever those vanadium carbides are present while using CrOx. As per "pulling" the vanadium from the steel, the way I always envisioned the cutting process of anything was that the individual abrasive particles act as pressure multipliers by exerting an input force over a significantly smaller surface area. So long as the abrasive doesn't deform, it cuts into the material by shearing it at the contact point in much the same way a paper cutter works. With this understanding, I'd imagine that the vanadium carbides would instead fall out on their own accord as the steel infrastructure holding them in place is cut away.

I've heard lots of talk about how diamonds are more edgy abrasives while everything else is more rounded which means it will, by nature, cut much more aggressively than other compounds since the surface area that is making contact with the edge is much smaller per particle size. With this being said, it seems like it would make more sense to get a ridiculously fine stone/plate and just use that to strop if diamonds are the only things hard enough to cut the vanadium carbides. In this case, it would seem that Wowbagger shares my mentality that it doesn't make any sense to use a dedicated strop for extra hard steels since the difference they would make is negligible at best.
Click to expand...

The carbides falling out is part of the problem in using abrasives that aren't able to cut or shape them instead. The gaps left behind, after the supporting matrix steel erodes from around the carbides, weaken the edge itself. The result is an edge that won't stay sharp as long and will be less durable, as the carbides themselves fall away and aren't present to add wear resistance and support to the edge. An example is how S30V behaves if a sub-par stropping abrasive is used in attempting to refine it. As I noticed with my own attempts with S30V some years ago, the edge can be made to shave/whittle hair in the very short-term on such a strop. But with S30V, as many have noticed, the really fine, hair-whittling sharpness would go away very quickly, because the fine edge was very, very weak. The fine edge collapses in simple tasks, even like cutting paper (this is what I noticed, after using a leather/green strop on S30V). Using an abrasive that's easily able to cut the carbides and shape them means the carbides won't fall away as readily, and will therefore add sharpness and support to the edge on their own. So for S30V, transitioning from green compound on leather, to something like a firm/hard wood strop with diamond compound, makes a night-vs-day difference in sharpness, polish and edge durability at that level of sharpness.

On the 2nd underlined point in the quoted post, whether a strop makes a difference or not is dependant on what it's used to accomplish and if the abrasive is adequate to the purpose. If the abrasive on the strop isn't ideally suited to the steel being refined or polished, then the strop may not add much refinement and might even degrade the edge, for the reason I mentioned above. On the other hand, if the abrasive is well-suited to the steel and technique is good, the strop can add a lot and do it very quickly and inexpensively. It can also extend the life of the edge between stonework by a large margin as well.
 
I dont strop to debur during sharpening. I draw the blade through wood or use a stropping motion on the next grit stone in my progression. I only leather strop at the end of my sharpening process as a way to clean the edge and give is that final zing.
 
You must log in or register to reply here.
Back
Top