Knife Sharpeners Surveyed
Three main approaches to knife sharpening existfreehand devices, angle-assist devices, and variable-angle devicesalong with a bewildering array of products.
Sharpening a knife or other edged tool is, in theory, simple and straightforward. However, in practice it's often complex and arcane. Many people are baffled by the required skills, and few are familiar with the wide and increasing variety of sharpeners available. This article is a blueprint for action. As you read it, you can appraise your sharpening needs as well as your skill level and then choose the most appropriate type of sharpener.
We've concentrated on three sharpener types here, along with a variety of offerings for each type, which will probably lead you to concentrate on one of the three. Then, instead of simply visiting a nearby dealer, you can browse manufacturers' websites so you can see all their offerings within that type. Then, after buying one, you can begin developing or improving your skills.
To begin, it's important that you have a knife worth sharpening! Quality knives can be kept extremely sharp and will reliably retain their edge. We suggest any of the nautical knives we've recommended in the past (see PS December 2004, PS March 2004 or PS June 2000). If you like your current knife, but it's quite dull, try returning it to the manufacturer. Many knife makers will resharpen blades for a modest fee. Either way, you start with a fresh, factory edge.
Cutting bends, and can break off, tiny pieces of the cutting edge, while sharpening removes enough metal to re-establish the bevel—that relatively thin area adjacent to the final cutting edge where the front and back of the blade meet. Ideally, a sharpener should be matched to your edge bevel by using manufacturer specifications, or by measurement. Unfortunately, the latter is usually impractical because the data are lacking. Experience and observation are your next-best and most practical guides.
Plain-edge blades can be sharpened with something as simple as sandpaper, either on a flat surface or held taut around a dowel, if you have the skill to maintain the proper angle. Failing that, a wide variety of devices can help.
Restoring serrated or scalloped edges to original factory condition is a job for the factory. At the DIY level, almost any sharpening you do will alter the original shape of the serrations or scallops. Since it's your knife now, not the factory's, and you want it sharp again, observe that most wear occurs at or near the tips of the scallops, so this is where to concentrate your sharpening efforts. The worn areas reflect light, whereas the sharp portions don't.
One approach is to touch up those worn areas using a small rounded sharpener while maintaining the original angle. A light, careful touch is needed. On serrated edges, the bevel is on the front of the blade, while the back is usually flat, so another technique is to create and maintain a very slight new bevel on the back of the blade, and leave the front alone. Once the new bevel is created, it is easy to maintain. Consistency of angle is key, however, and you want to remove a minimum amount of material. Both techniques yield better results if applied early on when serration wear is light. This review includes devices for both techniques.
We've grouped sharpeners into three general types: freehand (your skill is what establishes and maintains the sharpening angle, e.g., bench stones and pocket sharpeners), angle-assist (devices that generally make it easier for you to maintain an angle), and variable-angle (devices that let you choose the angle and help keep the blade in position). Not surprisingly, the more the device does for you, the more it costs.
We recommend medium grades of coarseness ("grit") of the abrasive; for very dull knives; start with whatever equates with coarse for that manufacturer. Don't depend on finding a grit-size listed, as with sandpaper: manufacturers don't often provide them. Fine and extra-fine grits may further improve a steel edge, but we suggest you omit them for cobalt and titanium blades, as they seem to cut better and longer without polished edges.
Most sharpeners come with at least some primitive advice on use. Excellent books on the topic are available from local libraries if you want to know more. The county library system we checked listed six, including an excellent video.
Before starting, paint your edge bevel with a non-permanent ink such as a whiteboard marker. Then you can observe where the sharpener removes it. If ink is being removed only at the cutting edge, then your sharpening angle is too broad; if only at the upper part of the bevel, then too narrow; if all the ink is being removed, the edge and sharpening angles agree.
Because so many of the blades PS has recommended have serrations, and there are so many sharpeners available, we evaluated only devices with claimed capability of sharpening both plain and serrated edges. We also included only those products that are used either dry or with no more than water, per manufacturer instructions, as well as those that require no external power. The accompanying table gives detailed information on one recommended sample of each type; brands offering devices with similar features are listed below in the same column. The contact information below has references for manufacturers of all the cited brands.
Freehand Sharpeners require good muscle memory to maintain a given angle, and frequent checking of the effects on the knife edge (we suggest frequent checks using a 5 to 10x magnifier). Without both consistency and feedback you will probably waste time and you may damage the blade. We have omitted traditional bench stones, although with skill they could be applied to serrations using the second of the two approaches above. Of chief interest in the freehand category are small cylindrical and tapered devices which can be used to sharpen one serration at a time. Use caution with freehand devices. If you can, first develop your skills on a cheap blade, and use a light touch on serrations.
Among these sharpeners we were most impressed with Mission Knives' Non Magnetic Sharpener, a tapered alumina ceramic model that's lightweight, collapsible and non-magnetic. If you have a serrated Spyderco or Cold Steel knife, Lansky offers inexpensive pocket-size sharpeners shaped to approximate the serrations of these respective products.
Angle-Assist Sharpeners make your job easier by de-skilling the task, e.g., they only require that you hold the knife vertical while running it across the sharpener. The sharpener is mounted at a preset angle, so the device creates the sharpening angle. This action resembles a normal diagonal cutting stroke, requiring little dexterity or new muscle memory. The best models offer various abrasive grades and more than one angle.
A versatile and easy to use model in this class is the Spyderco Tri-Angle, which offers two bevel angles, and three abrasive grades including optional diamond. Serrations are sharpened on the radiused corners of the triangular stones. A separate angle is provided for household scissors. The included parts, all of which may be removed and used separately, are stored conveniently in the hard plastic case, the bottom of which serves as the sharpeners' base.
Variable-Angle Sharpeners are more elaborate devices that let you set a desired sharpening angle, and then maintain it while you simply move the stone across the knife's edge. Their design yields repeatability with consequent savings in time and effort because every sharpening stroke is at the right angle; you’re never undoing previous progress by unconsciously altering the angle. We're talking "sharpening system" here, with a wide range of abrasive grades, materials and accessories. We were impressed by the results obtained on a variety of knives using the professional-level Edge Pro. Serrations are sharpened by the second method previously described above.
A high-quality nautical knife is only useful if it's kept sharp, so a good sharpener and sharpening skills are as necessary as a good knife itself. We’ve tried to fill this limited space with practical information to help readers take first steps toward developing skill in sharpening, by distinguishing among types of devices, and by detailing and recommending within each type a model of special interest.
Since sharp knives are far safer and more effective than dull ones, the results should make your effort worthwhile.
Also With This Article
"Value Guide: Knife Sharpeners"
• Blade Master, 800/251-7768, www.frostcutlery.com
• Buck, 800/326-2825, www.buckknives.com
• DMT, 800/666-4368, www.dmtsharp.com
• Edge Pro, 541/387-2222, www.edgeproinc.com
• Edgemaker, 419/478-4300, www.edgemaker.com
• EZE-LAP, 800/843-4815, www.eze-lap.com
• Gatco, 800/548-7427, www.greatamericantool.com
• Gerber, 800/950-6161, www.gerberblades.com
• Lansky, 716/877-7511, www.lansky.com
• Meyerco, www.meyercousa.com
• Mission, 214/455-3137, www.missionknives.com/home.htm
• Smith's, 800/221-4156, www.smithabrasives.com
• Spyderco, 800/525-7770, http://spyderco.com