Using newsprint as a repeatable test for comparing sharpness

[Dog of War]

The edge pro can be adjusted to any angle between it's max and min angles. I don't strop that much anymore since getting the ultra fine rods for the Sharpmaker. I usually like to go at least 3 degrees or more for the secondary bevel.

Thanks for that info. If the polish you get with the u-fine rods comes close to the level of sharpness you get from stropping, I could see big advantages to this over stropping.

After I'm done with the secondary on the Edge Pro, it's on the the ultra fine Spyderco rods for two or three very light passes on the corners and then one or two at a slightly higher angle. I've gotten great results with this procedure and it seems to produce the most durable edge so far.

Seeing the kind of care and precision some are using, I think it's time Spyderco think about a variable angle Sharpmaker.

I'm still surprised that fracturing would show up now after all the work you've done on that blade.

It explains to me some of the earlier results such as when it basically exploded on the plywood. As it is now it doesn't get much use. I have emailed Reeve about it with no responce. I might get it rehardened but that is difficult to do with the complex steels if the structure was damaged because they are difficult to normalize.

The Sebenza was interesting because I had been using it on the Sharpmaker for some time and then it just suddenly starting cracking apart and would not sharpen at all. I actually ground off a number of visible chips and there was no sharpening responce to the edge at all. I think what may have happened is that the primary edge grind was too low and the steel was fatigued and thus all that edge is now weakened steel.

That's a shame .... Reeves not responding, I mean. I would think a maker would at least like to see what's going on for himself. Can you post a link to that review or threads describing what happened with the plywood, etc.? I somehow missed that.

I wonder if the u-fine Sharpmaker rods might approach a level of finish and sharpness that rival stropping.

Yes, the fine ones alone give a high degree of push cutting. I have to check the Zubeng responce to different hones anyway so I can use it to benchmark the grits. It is near the ideal steel to use for such an evaluation because the carbide size is small and the hardness near optimal.

I've only heard a little about Zubeng. Sounds like this will be a very interesting review.

I still have a hard time getting consistent results stropping "regular", meaning non-Scandi, edges.

The steel on those knives has a large influence as well because it is optomized for that type of edge.

At some point I hope to reprofile at least a couple of Moras to full flat grind, so will add that to the list of things I want to look at. Somewhere I saw a picture of a Roselli UHC blade that was made that way, pretty much full flat grind and obviously very acute, but haven't been able to find one I could buy. If you know a source, let me know.

Even on a benchstone, I keep the pressure moderate.

Generally you want to keep the pressure to a minimum which produces aggressive cutting action because the higher the forces the more likely the edge will bend. After thinking about your comment recently I checked the no-name after regrinding and you can see a massive difference from the x-coarse DMT if you press very hard vs light. At maximal pressure there can be a deformation burr which is visible at about 0.2 mm wide it should have been obvious that this isn't a good idea in terms of trying to obtain a very sharp edge because none of that steel will form clean and the steel above it is likely highly stressed as well. Thanks for pointing that out.

Well, this is just one of those seat-of-pants things I decided was good practice, not necessarily with much understanding beyond avoiding obvious problems. Freehanding it's easy enough for me to get careless and have the blade contacting only the edge of the stone (one reason I like to carry a rounded slip stone for field sharpening, at least it's not as brutal when that happens) plus I found edge durability is better if your finish sharpening is done with a progressively lighter touch. Finally it occurred to me that the rounded belly, which is the part of a blade I usually use the most, gets a lot more pressure per unit of area than the straight part of the edge if you keep using the same sharpening force.

I've never heard of or thought to look for a deformation burr like that, but that seems reason enough right there. I'm not going to suggest you incorporate that as a regular test when reviewing knives, but in some instances it could be pretty interesting IMO.

 

[sodak]

Dog of War,

I tried using the Edgepro for microbeveling, but it was putting too much pressure on the edge for me. I would always end up with a wire edge. I'm kind of ham fisted, so keep that in mind. I'm sure others like Smegs do just fine with it. Also, the EP is narrower than my sharpening stoned, raising the contact pressure again. Like Smegs (and Cliff have) said, I try to raise a burr on both sides before going to the next higher grit. That's absolutely critical. Otherwise, I just waste an hour at the next higher grit. I used to have the feeling of wanting to polish the ege rather than cut into it, but now I'm starting to realize that without cutting into it, *real* sharpening (for me) just won't happen. YMMV.

I'm trying to do all of this without stropping. I have never had luck stropping with green chromium oxide compound. I probably get the angle too high and dull the edge. What I have had great success with is stropping with leather strops and regular straight razor compound (J55 or J56 from knifecenter.com). Keep in mind this is in direct contradiction with Verhoeven's report and photos, but that's what works for me. If the knife is reasonably sharp, I can strop it to absolutely screaming scary sharp with 10 strokes on the canvas side, and 20 on the leather. It's almost so easy it's like cheating, so I'm trying not to rely on the strop. Also, if the knife is iffy before the strop, I just raise a wire edge with stropping. So I have to have a good edge to start with.

By the way, great job Smegs on the SM/Endura numbers. Those are great! I'm thinking about buying my sister a SM for Christmas, you just pushed me over the edge.

Cliff, yeah, I wish we could compare knives. That customs on the border puts me off a little. 5/10 is pretty extreme to me, but then again, I've never gone that thin yet. I'm going to have to pick a knife and just do it... Maybe I'll try my Sebenza, it pretty much sits in the drawer anyway. Hmm...

PS - Don't get me started on plywood. I cleaned out my garage last weekend and had some 3/4 inch plywood to get rid of. Tried a bunch of different large blades with some interesting, some surprising results. My Busse Steelheart E was one of two that suffered absolutely *no* edge damage. I almost seemed to polish the edge up a little more. Unreal.

 

[Cliff Stamp]

For example, the Ronin blade - due to distal-tapered thin blade - simply flexes away from the stone for the forward 1/3 of the blade at high honing pressure.

I have found that you can work around this if you keep your off hand fingers on the blade. This is fairly dangerous for obvious reasons.

Seeing the kind of care and precision some are using, I think it's time Spyderco think about a variable angle Sharpmaker.

This would also eliminate any initial 1h+ regrinding. Use the most acute angle which sharpens efficiently and then just apply a relief grind as you get the time to gradually increase ease of sharpening and cutting ability. One solution would be to cut it in half and attach a hinge to the bottom. This allows any angle more obtuse than the preset. You also need some way to constrain the width in place but that isn't difficult.

...link to that review or threads describing what happened with the plywood

http://www.bladeforums.com/forums/showthread.php?t=386998

At some point I hope to reprofile at least a couple of Moras to full flat grind ...

Yeah, the only reason I have not done that to mine is I use them for stock references. From a functional point of view I would have hacked off the sabre grind a long time ago. I have ground them that way for friends. Makes a massive difference for sharpening and for many types of cutting. I don't recall a full flat UHC puukko/Mora, it would be an easy mod for any maker or anyone with Thom's patience.

I found edge durability is better if your finish sharpening is done with a progressively lighter touch.

Yes, any weakened steel is just horrible for edge retention. After recent work I am convinced that this is why people have such a horrible impression of many "low end" steels because they are so horrible to try to sharpen clean. I finally got the no-name to shave above the skin with a 600 DMT finish. Ok, not well, but you can tree top arm hair on a slice. I had to :

-form the primary on 200 SiC
-polish up to 0.5 micron
-sharpen at 600 DMT really light

The 600 DMT was a secondary bevel at about 11-12 on a 9-10 degree primary and took 100 feather light passes. This takes about 5-10 passes on a quality steel which doesn't need the primary polished either. The no-name can now push cut newsprint far past an inch and that and the shaving ability could be significantly improved with a higher polish. I was just using the 600 DMT for a slicing edge retention trial.

To polish the primary takes about 100 passes per side on the 200 grit, 200 with an 800, similar with a 1000, and again with a 4000. These are all small stones, 1"x4". This is only about five minutes and doesn't need to be ultra careful. I find waterstones fairly forgiving anyway. At each stage I check the edge under magnifiction to make sure it is even and the micro-serrations minimized.

The reason this is necessary is because you can't use much force with the 600 DMT or it burrs. You can't remove any large scratch or missing edge piece as that would take forever since the force is so low. This allows sharpening from start to finish in about 7-8 minutes. This is still really slow but it was taking me 15-20 minutes a week or so ago.

Finally it occurred to me that the rounded belly, which is the part of a blade I usually use the most, gets a lot more pressure per unit of area than the straight part of the edge if you keep using the same sharpening force.

That is an interesting obversation and certainly valid, I have not noticed this to be a problematic area. Often the initial part of the edge is the most troublesome because it will get far less abrasion than the rest of the edge simply due to it seeing a much smaller section of the stone, assuming you always start your sharpening pass there.

I try to raise a burr on both sides before going to the next higher grit. That's absolutely critical. Otherwise, I just waste an hour at the next higher grit.

That is the most common mistake people make. There is a common miconception that coarse edges can't be very sharp and thus it is never a goal. If you actually leave the edge damaged and don't fully cut it with the coarse stones then good luck on the fine ones.

Don't get me started on plywood. I cleaned out my garage last weekend and had some 3/4 inch plywood to get rid of. Tried a bunch of different large blades with some interesting, some surprising results. My Busse Steelheart E was one of two that suffered absolutely *no* edge damage. I almost seemed to polish the edge up a little more.

Yeah, it is lovely. Try chopping it up some time if you want to get out some frustration.

-Cliff

 

[db]

"
Cliff posted...

Yes, any weakened steel is just horrible for edge retention. After recent work I am convinced that this is why people have such a horrible impression of
many "low end" steels because they are so horrible to try to sharpen clean. I finally got the no-name to shave above the skin with a 600 DMT finish. Ok,
not well, but you can tree top arm hair on a slice. I had to :

-form the primary on 200 SiC
-polish up to 0.5 micron
-sharpen at 600 DMT really light

The 600 DMT was a secondary bevel at about 11-12 on a 9-10 degree primary and took 100 feather light passes. This takes about 5-10 passes on a quality steel
"

To polish the primary takes about 100 passes per side on the 200 grit, 200 with an 800, similar with a 1000, and again with a 4000. These are all small
stones, 1"x4". This is only about five minutes and doesn't need to be ultra careful. I find waterstones fairly forgiving anyway.

Are you now seeing the value of the finish on the primary?
"
At each stage I check
the edge under magnifiction to make sure it is even and the micro-serrations minimized.

And also the value of an even edge?

 

[Cliff Stamp]

Are you now seeing the value of the finish on the primary?

As noted in the above, the goal was to create an edge of a very specific profile for a stock comparison and thus the primary had to be ground at each step because of constraints on the edge geometry for the purpose of that comparison which would not allow use of microbevels. Of course with that constraint relaxed then multi-bevels would have been optimal. The same effective goal could also be achieved by adding a light micro-bevel at 10/12 with waterstone of suitable grit on top of the 200 silicon carbide primary and thus reducing the process to just two steps. But again, it was clear this was a constrained stock comparison, not a general sharpening method.

In addition, as I also noted in the above, this expanded method was only necessary because the steel was easily forming deformation burrs which prevented normal honing pressure with the diamond abrasives, this isn't an issue with knives which don't cost $2 because the steel which have a much higher strength/grindability ratio and of course have a much finer carbide and martensite structure. I have also noted in dozens of other such comparisons on the usual cutlery steels, this expanded method isn't necessary and you can just apply a direct microbevel as noted by Lee, there is no need or even benefit to working the entire primary. Of course a wider hone would minimize deformation burr formation.

And also the value of an even edge?

In the above I was discussing the properties of the very edge, the last 0.1 mm or so in width, and noting it had to be at the same finish because of the inability of the DMT hone to be used with a significant amount of force on that knife which is of very low quality steel not the cosmetic appearance of the actual bevel which I have noted many times previously holds no importance to me. The current primary edge bevel is actually very asymmetric in width because the primary grind is uneven. On one side the edge bevel actually intersects the top of the primary hollow grind, it also dips and waves along both sides due again to an unven primary hollow grind. The initial highly obtuse edge angle was cosmetically much more symmetric and of better finish. As I have noted many times before however, I sharpen knives so they cut well, not so they look pretty so I prefer the current finish over the initial one.

-Cliff