Sharpening tools properly must be one of the hardest lessons to learn in carpentry. And yet the path to success is simple. Unless you’re a tool junkie, or my friend Gary Katz, it doesn’t require fancy or expensive equipment.
Step One: Sharpness is nothing more than two flat surfaces, polished mirror smooth, meeting at an angle. Use a grinder to establish the angle. Thirty degrees is about right, but you’ll soon learn to get it right by eye. Pointier will cut more easily, shallower will be stronger. Grind the bevel side hollow. You will have ground enough when sparks start coming over the top.
Step Two: Check the chisel for square frequently and use a gentle touch. Dip the tool in water or oil often to cool it. (I use an inexpensive magnetic mist sprayer.) If it gets hot enough to discolor you will have ruined the temper.
Step Three: Hone the bevel on an oil-stone or water stone—I use a medium India—secured in a clamp or fixture. If you hold it in your hand you will probably be wearing a band-aid soon after. Rest the tool on the bevel and don’t tip it up or down as you sharpen. Use small circular motions and move over the entire surface of the stone so you don’t wear it hollow. All you are doing is removing the coarse scratches made by the grinder—it doesn’t take a lot of pressure, just a little patience.
Step Four: Hone the back of the tool. Hold the back absolutely flat on the stone. You are polishing out any scratches or pits on the back, making sure the back is flat, and removing the burr left by the earlier steps. This step may take a few minutes on a new tool, but only seconds to retouch a tool that has been properly sharpened before.
Step Five: Stropping is the step most carpenters skip, which is why most carpenters are working with dull tools. I use a piece of leather glued to a block of wood. Charge the strop with buffing compound. My favorite is Herb Dunkle’s Yellowstone.
Step Six: Strop the tool by pulling it backwards over the leather—back side first, then the bevel. Hold the tool flat on the leather so you don’t round the bevel over. In a moment you will be able to see your reflection in the edge of the tool.
Step Seven: When you can shave with your chisel or plane iron, then it’s sharp enough to cut wood—even curly hardwood or across redwood end grain.
(This article originally appeared on GaryMKatz.com)