Lesson #32: Reducing knife breakage ...
(contributed by Dave Bull)
Although in my earliest days of printmaking I used a single knife blade for years on end, I've got a bit smarter as I've got a bit older (or at least a bit less stupid, anyway), and now sharpen my tools frequently. Knife blades now last me a couple of months at the longest ...
Frequent sharpening is imperative given the delicacy of the carving that I do, and I don't begrudge it - what I used to consider a 'chore' I now just consider 'part of the job', and don't hesitate to turn to the stone whenever the tool feels even slightly dull.
But what is undeniably frustrating is to spend a few minutes carefully putting a fine edge on the blade, only to have the tip then break off in the first few seconds of use. And not only frustrating, but wasteful; there goes another millimetre or so of fine steel, wasted ...
There is a small 'trick' though that can be used when doing certain kinds of carving that will greatly reduce 'tip' breakage. 'Normal' sharpening leaves the point of the knife in a perfect 'point' shape - the bevel of the blade and one edge of the blade come together in a perfectly sharp angle. Exactly what angle is chosen depends on the carver's preferences, the type of work being done, and the wood in use. But the 'finer' the angle chosen, the more likely it is that the point will soon break.
To reduce this breakage, rub the back edge of the knife blade very lightly against the stone at such an angle as to 'bevel' the back edge of the tip of the knife. Only one or two gentle strokes against the stone will be necessary. If you do this as the final step in sharpening, the angle at the extreme tip of the blade will be reduced slightly, and the tip will be far more resistant to breakage.
Of course, it also means that the point will be less 'fine', and this method cannot be used when extremely delicate work is being done, but for most general cutting, such a blade will still cut smoothly, and even with the reduced angle, it should still turn most corners readily.
Please try it - I think you will find that it greatly extends your blade life.