Part 2 of 2
Chefs require a keen edge for chopping and dicing vegetables and meats. I watched a chef in a Winnipeg restaurant grind a dull knife on a 1000x water stone, followed by a honing on a 6000x water stone. His experience was evident in his ability to hold the knife at a constant 20-degree angle while he spent about 20 minutes working the edge on the 1000x stone, followed by another 20 minutes on the 6000x stone. The result was a superb cutting edge that sliced a tomato into ultra thin pieces in seconds.
For those of us with less experience, there are jigs available on the Internet that hold a knife at a precise angle while it is being sharpened on a flat stone. There are a variety of stones available, including water, oil, diamond and ceramic ones, as well as slip stones that are used to remove a burr from the back of a flat chisel, gouge, plane blade or whatever piece of steel is being sharpened.
Slip stones come in many shapes, the most useful being ones with both flat and rounded surfaces for working the back of a blade or the inside curve of a gouge. Most stones are composites; however, there are natural materials on the market such as Belgian Blue Whetstones and three or four kinds of Arkansas stones. As a rule of thumb, natural stones are not as consistent throughout as modern composite materials and therefore do not yield the consistent results of composites. However, they are still in use by people who grew up using them to sharpen knives and other blades. Choosing a stone is a matter of experience and preference.
Taylor Hoogstraten, a wood restoration expert with Parks Canada who works out of Lower Fort Garry, prefers to sharpen his chisels on a 1000x water stone, switching to about a 6000x to add a thin micro bevel to the cutting edge. Though Hoogstraten has years of experience as a woodworker, he still uses an adjustable jig to hold a chisel at the exact angle of the main bevel while grinding the tool.
To add a micro bevel, he slightly increases the angle of the jig and then runs the chisel’s blade across the surface of the 6000x stone. The result is an ultra-keen edge that is not rounded. As Hoogstraten says: “It is possible to hand-hold a chisel while sharpening it, but the jig assures me that my angle of attack will not change. It only requires rocking the chisel by a couple of degrees to create a rounded edge that may look sharp but will not cut cleanly.”
His jig has two legs: the back one is equipped with a roller that rests on a bench; the front leg has a jaw to hold a chisel or other blade. This leg is infinitely adjustable so the chisel’s main bevel (usually 25 to 30 degrees) can sit flat on the surface of the sharpening stone. Hoogstraten doesn’t recall where he bought the jig, but Lee Valley sells a similar tool called the MK II honing guide for about $70.
Hoogstraten added that he prefers soft, white grinding wheels made by Norton because “they won’t overheat a blade and ruin its temper. The only down side is that they tend to wear more quickly than harder stones.”
If you want to spend a lot of money, there are a number of power sharpeners on the market that are an expensive variation of the reversible 3/8-inch drill and disc sharpener discussed earlier.
There are also gadgets available that, in my experience, are a waste of time and money. One is a board drilled with holes at various angles into which ceramic rods are placed. A knife held at 90 degrees is drawn down the length of the angled rods to produce a keen edge. The results are okay if the blade is to be used for general kitchen work, but this kind of edge is not of sufficient quality for fine woodworking or fine culinary work. Another product to be wary of is a knife sharpener with a carbide cutter encased in a polymer holder. The cutting edge produced by such a toy is mediocre at best.
Woodturning chisels are generally sharpened on an 80-grit to 100-grit wheel that is water-cooled to prevent overheating. People who earn a living as wood turners may sharpen a roughing gouge after every five to six cuts on exceptionally hard or abrasive wood. As a result, the burr raised on a turning chisel by the grinding wheel is usually removed by a couple of light passes of a slip stone; further honing and polishing are a waste of precious time.
A burr is desirable on scrapers because in this case the wire edge does the cutting. With most turning chisels, the main objective is to maintain a primary bevel of between 30 to 45 degrees; micro-bevels are not required as they can impede the cutting efficiency of a turning tool.
My experience with turning chisels suggests that inexpensive tools with short blades and handles are dangerous to work with as they can be yanked out of a turner’s hands. The handles of quality chisels should be long enough to be held close to the body and tucked under an armpit. The blades should be at least one-third the length of the handles and made from a continuous length of high speed steel, not laminated to a cheaper piece of less expensive carbon steel.
To remove wood properly, a lathe should be heavy and, if possible, bolted to a concrete floor to reduce movement and vibration that can make it nearly impossible to turn an exquisite bowl or a cleanly cut banister spindle.
If you want to enjoy the experience of wood turning, buy good chisels and a quality lathe. The difference is like playing a cheap guitar compared to an expensive one. No joy with the first, great pleasure with the second.
(For an excellent introduction to wood turning, I recommend Turning Wood with Richard Raffan published by Fine Woodworking. It is available used on the Internet.)