The following is an excerpt from “Sharpen This” by Christopher Schwarz.
One of the most frequent (and unanswerable) questions I get about sharpening is: How often should I sharpen?
The correct but unsatisfactory answer is: Pretty much any time the question “Should I sharpen?” pops into your head.
When I ask myself that question, I stop and look at my tool’s edge. Can I see a glint of light at the tip of the bevel? If I can, it’s time to sharpen. I look at my work to see if the surface is clean or if it’s marred by fine white lines or scratches in the wood. If I can see those lines, the edge is likely damaged and needs to be reground. And I think about the last few minutes of work I’ve done. If the work took more effort than expected, it’s time to sharpen.
You also have to become sensitive to the peculiarities of your tools. There are times when the tool’s cutting edge is not causing the problem. That is, you sharpened the edge, and the problem persists. What do you do then?
Well the good news is that by taking a moment to sharpen the tool you have eliminated the most common ailment of a hand tool: the edge is dull. After that, you need to consider the other parts of the tool. If your handplane is leaving a rough surface in its wake, the problem could be that its sole has become dented somewhere around its rim. So you need to file away any roughness on the sole. If the plane is too hard to push, there’s a good chance that the tool’s chipbreaker is too close to the cutting edge, which can create some impressive resistance. And if the plane is both too hard to push and it is leaving a nasty surface on your wood, there’s a good chance that the chipbreaker has slipped forward of your cutting edge and so the chipbreaker is doing the cutting – instead of the tool’s cutting edge. This is a common problem.
If a sharpening session doesn’t fix a chisel, there’s a good chance that your sharpening efforts did not cut a new zero-radius intersection. This is also a common malady among beginning woodworkers.
But in all honesty, sharpness fixes almost everything.
As you become proficient at sharpening, you will find there is a pattern or rhythm to the process, and it is mostly circular, like the life cycle of a frog. It starts as a tadpole that grows into a frog and then creates the next generation of tadpoles. With tools it is hone, polish, hone, polish, hone, polish, grind – then repeat the cycle. The following flow chart will – I hope – show you how sharpening occurs in a workshop during the long haul. It might take a chisel a year to make it around the circle. Or a week. It really depends on how much you use your tools and how hard you are on them.
The flowchart (below) begins the moment you decide a tool is dull.
Great flow chart!!