As a home cook, I have an interest in knife sharpening. I very much appreciate your well documented and scientific approach to sharpening...especially your microscope pics.

After getting all my knives to a polished razor edge, the joy of razor sharp slicing gives way to the reality of preparing daily meals. After a week or two, I re-examined the blades of my go-to knives (I have a $20 USB microscope, which is nowhere near the quality of yours, but is still a very helpful tool). Not surprisingly, there were nicks and edge-rolls. So comes the question - do I pull out a sharpening setup or give it a few strokes with a steel ?

The popular wisdom of a steel simply straightening the edge is complete BS from what I've seen. Mine aggressively removes metal, my angle control is imprecise and the previous precision angle-controlled polishing is pretty well torn up. That said, there is an improvement in cutting ability (though not as good as freshly sharpened), it's quick and easy, and looks cool in front of dinner guests.

It would be great to see an analysis of what sharpening steels really do, with recommendations on when and how to use (or not) in a real world kitchen.


Roger

Hi Roger,

Welcome to the forums and an intesting question you ask!

I have never actually tested what these rods do, so I cannot answer from personal experience. Hopefully there are people here who can. And since you have a microscope yourself, maybe you can try to see under the microscope what actually happens.

But as far as I understand it from what I have read, steel rods don't sharpen an edge: steel on steel generally doesn't remove metal (substantially). They may however be good at removing a burr that results from the use of a knife.

Ceramics are usually harder than steel, so they do remove metal. So, at least in theory, they could be used to sharpen knives. That is also your experience if I read it correctly. But indeed then you get into the problem of inconsistent angles, which may do more harm to an edge than good.

Personally I don't use these rods at all anymore (not even to look cool in front of guests ). It is very easy to do touchups of kitchen knives on the WEPS ceramics (provided you gave them a regrind initially and used the depth key and the ruler). It really is only a matter of minutes and I do this about every 2 weeks (for our amateur kitchen). Works very well and the knives are always sharp.

Welcome aboard, Roger!

You asked a very good question, indeed!

Personally, I'm not a fan of metal sharpening steels. A ceramic rod will do better justice in between sharpening.

If you were a pro chef in the middle of your prep and your knife was dying, you couldn't just whip out your WEPS and sharpen or touch up your knife - not without some stares, anyway! The ceramic rod will do the job of touching up the edge on the fly until you can sit back down and properly maintain/sharpen the knife again on the WEPS. Just be aware that your overall refinement will slowly be reduced to the grit of the ceramic steel rod (about 1,000-1600 grit).

However, you are a home cook, so you can do whatever you want!

IMO, if your edge isn't holding up for the entire prep, then you should consider adding a micro bevel or using a slightly more obtuse angle on the knife rather than fiddling with a steel of any kind. If you are simply experiencing normal wear on the edge (which is what it sounds like here), you can return to the WEPS and do a few strokes on your final grit rather than a whole new sharpening session.

Lots of guys also have a loaded strop for light touching up in-between meals.

What is your final grit when you sharpen you kitchen knives?

The previous 2 posts ask a few questions and make a few statements. I'll address them one at a time as best my current understanding permits.

"steel on steel generally doesn't remove metal"
........It does. See attached Pics

"The ceramic rod will do the job of touching up the edge on the fly"
......I don't have experience with a ceramic rod, but have long used a "diamond steel" which I believe to be around 1000 grit (not sure on that number, I'll get some pics soon and see if I can confirm or refine it). I've used the diamond steel for years, but have never been happy. It always produced a mediocre edge. I recently rediscovered my old steel, and it creates a sharper feeling and faster cutting edge, much to my surprise. Now that I have a microscope, I'm even more surprised how the steel tears up my pretty polished edge, but seems to work in its own way. Hence, my original post. I was kinda hoping someone already researched this paradox.

"What is your final grit when you sharpen you kitchen knives?"
.......Currently, I've sharpened them to a .3 micron grit with a convex bevel starting at 17 deg and tapering to 18.5 degrees. I'm going to be redoing them at something more like 20 deg tapered to 21.5 to make them more durable. I'm not sure my pork chop can tell the difference between 5 and .3 microns, but it feels cool taking it all the way.

"maybe you can try to see under the microscope what actually happens"
....OK, looks like I've got another project. Here's what I've done so far

I've taken a really crappy knife (supermarket type Hampton Forge chefs knife), honed it to 19 degrees, 15 microns, and gave it 6 firm swipes (probably not optimal technique) with 3 different steels, re-honing after each steel. I'm not seeking optimum results on a well honed quality blade here, just showing what a steel does.

The 3 steels used are:
1. An old Chicago Cutlery steel (they used to make reasonably good stuff)
2. A no-name discount store steel
3. A new Henckels steel

The 4 attached pictures are as follows:

Steel 4 The Honed blade before using the steel



steel 5 After using Chicago cutlery steel



steel 7 After using No-Name steel



steel 8 After using Henckels steel




Clearly, all 3 have removed metal. A wipe down of the rods with a paper towel confirms this. The edge, only honed to 15 microns, isn't pretty any more. It's even uglier on a finely honed edge. But again, the paradox.....it cuts well. The guys who cut meat all day for a living know this. Not as well as a freshly sub-micron honed blade, but definitely better than my "diamond steel", or "fine" diamond stone. at some point, a smaller grit size produces a superior cutting edge than a steel. I don't know where that point is, or how to optimally use a steel in combination with a quality hone.

Unless someone can enlighten me, I'll have to do some more work on what is an optimal technique, if any, for using a steel on a well honed blade in need of a minor tune up.

Roger

Meant a CONVEX bevel, not concave.

Hi Roger,

Is it just me or does it look like each rod kind of ruined the edge? I can imagine the knife still cuts meat (the edge seems quite toothy), but I cannot imagine it still cuts paper well.

mark76 wrote:


Not ruined... just made more toothy lol. I love toothy edges myself... and I have seen several edges that Clay has done where he will refine the edge up to a mirror finish and then micro bevel a toothy edge of the edge on it. I actually have a lot of experience with the ceramic rod and I love it... it actually does maintain my edge for a much longer amount of time than if I did not use one, and I don't have to whip out my WEPS every few days. I actually try to use it about every other time I use my kitchen knives. It does remove a small amount of steel while not removing too much.

If you want one that will not remove any steel at all but still will align the edge, get a smooth butcher steel. I am assuming the steel you have has the vertical grooves in it? If so, this will actually remove a lot of metal, more than the ceramic will. I have both a smooth butcher steel and a ceramic steel. I prefer the ceramic as I like to remove a minute amount of metal from my edge each time, but to each his own

Here you go... check this article out about steeling edges by Chad Ward that I found on the net, may be of some help, especially on how to find the right angle.

My use of the steel in the pics was with moderate pressure on a cheap knife, to provide an initial demolition of the "steels do not remove metal" theory. This, of course, undermines the credibility of everything we hear about steels. That said, the thousands or meat cutting professionals who walk around with a steel in their belt probably know something (despite lacking microscopes). The many pieces I've read and videos I've watched usually say light pressure should be used, so a lot more testing is needed to show a more optimum treatment.

From past experience (before I got a microscope and sub-micron abrasives and became all scientific), I've observed the following:

A fine diamond stone followed by 2000 grit sandpaper beats the stone followed by a "Diamond steel"

A fine diamond stone followed by an aggressive steeling beats the above. 2000 grit before the steel had little or no effect....no surprise, since the steel obliterates the original edge.

A finely honed blade beats all of the above.

All of this raises more questions than it answers, doesn't it ?

Hi Josh:

All 3 steels were grooved. I haven't seen any smooth steels around - I'll have to find one.

Nice article you referred to. I still need to do some testing, though.

As for your comment about a "toothy" edge, I suspect it's partially true, but there may be another force at work. The steel grooves act like a file, carving microscopic shavings off the edge. These resulting shavings, and the substrate they were shaved off, can be VERY sharp.

Unfortunately, I don't think my cheap microscope can resolve the cutting edge well enough to visually ascertain sharpness, so in the end, I'll need to do more subjective testing - like slicing tomatoes and carrots

[quote="razoredgeknives" post=2933]mark76 wrote:


So you put a microbevel on the edge using a rod? That seems quite a different use of the rod that Chad Ward writes about and as a always understood the use of a rod. Ur izzit me? (Accent Inspector Clouseau.)