Home knife sharpening tools
- David Kahn Apr 9, 2008 04:02 PM
I guess I can understand why a professional chef working 12 hours a day, six or seven days a week, wouldn't want to sharpen his or her own knives, particularly if he or she is using a relatively inexpensive stainless steel blade that gets lots of use and is probably replaced every couple of years. In my experience, however, the guys who are using really good, expensive, handmade blades always sharpen them themselves. (I haven't asked him, but I can pretty much guarantee that Chef Urasawa isn't letting anyone else touch, let alone sharpen, any of his beautiful handmade chef's knives.)
Maybe it's just me, but I think knowing how to maintain your tools is an important part of knowing how to use them. Putting a great edge on your own kitchen knives is not difficult, it just takes a little practice, patience, and some time. A set of good ceramic sharpening sticks (like these: http://www.lanskysharpeners.com/LCSGM... or these: http://spyderco.com/catalog/details.p... ) work reasonably well, aren't too expensive, and, unlike the electric grinders that many "professionals" use, there is virtually no possibility that they will ruin your knives by over grinding them or drawing their temper. Or, invest in a set of Japanese waterstones (http://www.japanwoodworker.com/dept.a... ) and learn how to use them. I am willing to bet that you can get a finer, longer lasting edge this way than you'll ever see from somebody you pay to sharpen your knives.
Just my 2¢. I'll get off my soap box now.
I dunno, I have the time, but not the great tools the guy at the shaver shop has. I'll more likely trust my expensive knives to a guy with years of experience than little old me starting out.
Price wise, think of it this way-a knife ruined by an amatuer is more expensive to replace than sharpening service by a pro.
I use Chef's Choice model # 130 sharpener, and am extremely pleased with the results I get. No shlepping, no gas expense, no waiting.
As far as sharpening systems go the EdgePro is one of the best. Not cheap but it cost less than a lot of Japanese knives and it will last a life time. You may have to replace stones on occasion. I have the Apex model and really like it a lot. Near perfect edges from your first attempt.
I was thinking about getting into this. What's better for manual sharpening? Whetstones or ceramic rods? What about my serrated bread knife?
I don't see why a wheel grinder or belt sander wouldn't do the job, but the consequences of error would be worse. Still, you could set up some kind of jig to keep the edge angle correct.
Knives are generally made out of hardened steel. Steel is hardened by heating it up to critical temperature (generally somewhere between 1500F and 1800F, depending on the alloy and carbon content) and then cooling it down rapidly by quenching it in a cooler medium (water, oil, air, etc., again depending on the alloy and carbon content). Once it's hardened, if you heat it up too much, it will lose some or all of its hardness. This softening process is called tempering, and usually begins at around 300F. Generally, the higher the temperature and the longer the duration of exposure, the more hardness is lost. Sometimes tempering is done deliberately because the knifemaker wants to trade off some hardness for increased toughness, but if the steel is tempered too much or at too high a temperature, it will loose too much hardness and no longer hold an edge well. When you use powered tools to sharpen a blade, the friction of the abrasive moving very quickly over a very fine edge can easily overheat the edge and cause it to soften. Depending on the particular steel type, tempering is sometimes accompanied by oxidation which causes the surface color of the metal to change, first to a straw/yellow, then to purple, then to blue, and finally to gray. Over tempering is sometimes called "drawing the temper" of a blade, and depending on how far back from the edge the heat damage extends, the blade can be merely damaged or totally ruined.
When you sharpen something manually, in contrast, the cutting action of the abrasives work much more slowly and don't generally get hot enough for this problem to occur. Another solution to this problem is to use powered equipment in conjunction with some sort of lubricating coolant, like water or oil, but this sort of equipment is probably beyond the reach of most home knife users. (This is how the old-time whetstones worked.) The other problem with powered sharpening equipment is that, even if it doesn't overheat the steel, it can remove a lot of metal very quickly. If not used properly, powered sharpeners can easily over-grind a blade, which can shorten blade life and/or ruin edge geometry. There are a number of good manual sharpening systems out there (a couple of which have been recommended by me and others on this thread), depending on how much one wants to spend and how into sharpening one wants to get. My view, fwiw, is that most people are much better off staying away from powered sharpeners.
So, there you have it -- more than you ever wanted to know or read, I'm sure. I've spent altogether too much time studying this subject because I'm an amateur blacksmith and knifemaker, and this is all stuff one needs to know to produce a good knife. (Some of my work is here: http://rhinoworks.50webs.com/knives.html ).
There are three professional knife sharpeners in the U.S. that I would trust my knives with. So iIlearned how to do it myself from one of those three.