How do you all sharpen?

[Ankerson]

Once I set the bevels to 15 DPS on the Edge Pro I strop to touch up when needed on a SIC loaded strop.

 

[Cyrano]

The Worksharp Ken Onion edition, with its Blade Grinding Attachment, does a great job on all my edged tools: chef's knives, hunting/outdoor knives, and folding pocket knives, including my Sebenza. I like that I can create a very good edge on any knife, no matter what its starting condition, in a matter of minutes, not hours.

Initial re-profiling of a blade (using a coarse abrasive belt) demands very careful attention, of course, to avoid removing too much steel. After that, refining the convex edge -- and maintaining the convex edge -- is quick and easy, using just extra-fine abrasive belts, and/or a leather strop belt loaded with honing compound.

Here's the edge I put on my Sebenza:

 

[unit]

.... in a matter of minutes, not hours.

No disrespect intended, but every time I see this phrase posted I immediately wonder where anyone would get the notion that any knife would take hours to sharpen. I have repaired significant damage in 10 inch super steel competition blades with simple diamond hones and never spent hours on one.

Powered systems are fast, but a decent set of hones will still get fantastic results in minutes.

 

[Cyrano]

No disrespect intended, but every time I see this phrase posted I immediately wonder where anyone would get the notion that any knife would take hours to sharpen ...

My comment reflects reading posts from users of high-end guided sharpening systems (e.g., EPA, WE) who report spending hours to achieve the results they wanted.

 

[newdebate]

The Worksharp Ken Onion edition, with its Blade Grinding Attachment, does a great job on all my edged tools: chef's knives, hunting/outdoor knives, and folding pocket knives, including my Sebenza. I like that I can create a very good edge on any knife, no matter what its starting condition, in a matter of minutes, not hours.

Initial re-profiling of a blade (using a coarse abrasive belt) demands very careful attention, of course, to avoid removing too much steel. After that, refining the convex edge -- and maintaining the convex edge -- is quick and easy, using just extra-fine abrasive belts, and/or a leather strop belt loaded with honing compound.

Here's the edge I put on my Sebenza:

The edge looks burnt?

 

[whateatsrabbits]

strop and ceramic rod has worked wonders for my 25, when the time come to reprofile I will use my edge pro.

 

[NvG79]

Prefered sharpening is my wicked edge! Put a 36 degr incl edge on my CR's, finishing on a strop...... Loaded with black/green/white compound and 0,5 micron diamond spray! I do notice a difference in the old and new hardening of the S35vn...... My new lnkosi stays sharp for a while longer than for example my 25

 

[Cyrano]

The edge looks burnt?

No, not burnt; just an artifact of the microscopy. I wanted to show as much of the edge as possible without blown-out highlights, so I used a polarizer. For smooth surfaces, the polarizer can filter out almost all reflected light, resulting in a dark area in the photograph. This dark area appears as a thin band along the edge because only that portion of the convex surface is at an angle for which the reflected light is being so effectively blocked by the polarizer.

These two photos show this effect clearly. They show the same region of the edge, but appear very different. In the first photo, the apex region of the edge appears brighter than the rest of the edge -- but in the second photo, the apex region appears darker than the rest of the edge:

I don't see how one could burn a blade using this tool. Hand-holding the blade against the belt, the temperature of the steel is always obvious. I expect one would drop the blade in pain long before it got anywhere near hot enough to burn. In my use of the tool, the blade edge never gets beyond warm.

 

[Nomo4me]

The edge looks burnt?

I think that's a lighting artifact. Doesn't look burnt to me, but looks overly (for me) convexed. That's the bugaboo of the WSKO with blade grinding attachment: not much selection in the way of belts and they are expensive, so users tend to use worn out belts.
There is no supporting platen so dull belts on this implement lead to highly convexed edges on high-end steels.

 

[Cyrano]

... There is no supporting platen so dull belts on this implement lead to highly convexed edges on high-end steels.

Can you explain the mechanism here? Why would worn-out belts create a different edge geometry from fresh belts?

 

[Nomo4me]

Can you explain the mechanism here? Why would worn-out belts create a different edge geometry from fresh belts?

Dull belts have a harder time abrading the metal and will tend to wrap around the flat plane of the bevel, thus more effectively abrading away at the heel and apex.
With a platen to prevent belt flex this isn't a problem, but one does need to be wary of heat build up blah blah blah

Loved my WSKO when the belts were new. Now not so much.

 

[kwackster]

@Cyrano: where can i find such a polarizer ?
From your pictures it seems like i could use one of those as well, as the pics below i took with a USB-camera from the edge on my PM2 in S110V steel also show those blown-out highlights, and they manage to hide the actual bevel surface quite badly.
BTW: the edge was done on Paper Wheels with various diamond compounds, my preferred sharpening method on high vanadium carbide steel types.

 

[Cyrano]

Dull belts have a harder time abrading the metal ...

Thanks for the explanation.

In the example I showed, the belts were brand new -- so the degree of convexing is 100% on me, not on tool wearout.

Can you share your criteria for how much convexing is good, vs. too much convexing? To my eye, all the edge profiles I create using the WSKO/BGA appear similar. I have no points of comparison for how the performance of a less-convexed edge would compare to the highly-convexed edges I've been making.

 

[unit]

I don't see how one could burn a blade using this tool. Hand-holding the blade against the belt, the temperature of the steel is always obvious. I expect one would drop the blade in pain long before it got anywhere near hot enough to burn. In my use of the tool, the blade edge never gets beyond warm.

Apparently it it pretty easy. The temperature you feel is a minuscule fraction of what occurs at the high surface area regions (apex and tip).

Many before you have impacted heat treat with powered systems and many of them had quite a bit of confidence. Over the years I have been tasked with repair of a few of these, and it's rarely as simple of a fix as the owner wanted. I'm glad you have learned what you need to get the results you want. Just continue to be ever vigilant because sometimes everything looks fine, but the edge just won't last like it should.

 

[Cyrano]

@Cyrano: where can i find such a polarizer ?

Polarization came built-in to my microscope, so I can't suggest a specific source, but accessory solutions for polarized-light microscopy are widely available.

In my experience, ease-of-use is just as important as optical performance, so I suggest finding a polarizing solution which is designed specifically for your type of 'scope. The large online microscope retailers should be able to help you find the right product.

 

[Cyrano]

Apparently it it pretty easy. The temperature you feel is a minuscule fraction of what occurs at the high surface area regions (apex and tip).

Many before you have impacted heat treat with powered systems and many of them had quite a bit of confidence. ...

Fascinating!

How do experts (like custom makers) manage this liability? Isn't edge sharpening typically done by hand, on a belt sander, as one of the final operations in making a knife?

And for non-experts like me: is there any measurement/inspection/test technology which can be used at home to address this concern?

 

[unit]

Fascinating!

How do experts (like custom makers) manage this liability? Isn't edge sharpening typically done by hand, on a belt sander, as one of the final operations in making a knife?

And for non-experts like me: is there any measurement/inspection/test technology which can be used at home to address this concern?

That is a great question. And I would suggest that experts have enough experience to improve their technique and limit the number of mistakes to very few....but to presume that any maker or manufacture NEVER makes such a mistake would be poor judgment. The best makers and manufacturers have QC that catches most or hopefully all of such mistakes.

Some users make policy to re-edge a knife upon recept if the edge was formed wiht powered means. Some have done enough experimenting to have suggested to themself that a low-speed edge will outperform a high-speed one...and others simply like to have their own edges on a knife.

With regards to liability...yes, it looks really bad when a maker puts out a knife and the edge holding falls short...but I think most makers (that we have heard of) are diligent enough that there are very few or zero that fall through the cracks. But it happens...and if it happens much, we hear a lot about those makers

How can you tell if there is a problem? It all depends on how astute you are to observation. Some knife guys sharpen VERY frequently and spend more time talking about, collecting, photographing, polishing, etc. THese guys will likely never know or care...and that is totally fine, because their enjoyment of the hobby does not put much premium on the knife's ability to perform at the top of its game. Others use their knife a lot and will pick up on subtle differences in performance (even the ones that happen weeks or months after the last profiling). These guys will often pick up on subtle changes they made while re-profiling and honing and figure out that some methods work FAR better down the road. Bottom line is, if your knife NEEDS to be sharpened as often as some guys sharpen, there probably is a problem...but if you sharpen every time the knife fails to whittle a hair...you have never really experienced more than what a pesky burr could have done

Some freaks get into competition and REALLY push hard to find an "edge" against competitors that have twice the body weight and 3 times the strength. These silly people would spend *hours* on the hones with several identical knives putting different V-edges (angles), degrees of convexity, levels of polish, stepped progressions, skipped progressions, and other silly witch craft-type cookery to try and pen the ideal recipe for cutting performance. And the funny thing is, at some level cutter style comes into play (even for a competition that utilizes the same list of materials and cuts). (Note hours spent is due to MULTIPLE knives)

And for sure, folders are different from competition blades...but know that these silly freaks apply the same rigor to their folders, because, well, they are weird freaks...and they are just as important as the guy that has a stack of knives in a safe that NEVER get used, frequently get photographed, and appreciated just the same.

Where are you on the scale of appreciators? (Rhetorical). If you think you are a freak, start playing around and experimenting. That is the only way you will get the answers that are right for you...just remember that you need to try (and become VERY proficient with) a LOT of things before you can rule them out

It is a fun hobby, and there is a LOT to these VERY simple tools. Sure you only need to grind two faces to an apex to have "sharp", but somehow it gets a lot more involved than that.

 

[Nomo4me]

Cyrano:
"
Can you share your criteria for how much convexing is good, vs. too much convexing? To my eye, all the edge profiles I create using the WSKO/BGA appear similar. I have no points of comparison for how the performance of a less-convexed edge would compare to the highly-convexed edges I've been making. "



Sorry, I've no such criteria to share in that regard. I haven't hunted big game in 25 years (buck 110 sharpened on a bench grinder back then). I don't do bush crafting and tend to grab a bow saw or lopper for yard work where some here would go hog wild with a heavy knife and head to youtube.
I'm not condemning -nor arguing against the benefit of - convexing of edges as a geometry to enhance durability where needed. What I do see however is guys proclaiming the benefits of a convexed edge when they are using tools that lead inevitably to heavy convexing.
So the arena where I use knives heavily is in the kitchen. A convexed edge is great on a boning knife, but anything that will go through veggies I want nice flat bevels, and tend to become annoyed when employing methods & equipment that biases toward convexing.
We all like what we like, right?

 

[unit]

Regarding the concept of degree of convex...It is VERY similar to the discussion of "what bevel angle is best?"

Simply put, a convex edge forces the material apart more over a given distance than a less convex edge, which in turn forces the material apart more over the same distance than a V edge, which forces the material apart more over the same distance than a more acute V edge. This all becomes moot once we arrive at the back bevel which controls the separation/wedging effect after that point.

Those that have really pondered it and experimented with it will likely agree that the differences are:
1. Durability
2. Perceived sharpness when testing or cutting things like (paper, thin items (1mm thick or less), opening mail, shaving hair, whittling hair, etc.)

No wrong answer here, but if you want to sharpen very infrequently, go with a steep convex, but if you want a knife that really zips you're mail open (or impresses most people that you allow to handle your blade), go with an acute V-grind.

I have taken a few blades down below 10 degrees inclusive, and they are really impressive with a zero grind...but you should not expect to act carelessly wiht such a grind. Those that shave with a proplerly honed straight razor have a pretty good idea what I am discussing here.

 

[Cyrano]

@unit: I did an experiment to measure the temperature at a blade edge during grinding on the WSKO/BGA -- posted in the Maintenance forum.