Keeping the Edge

(or Why Do You Look So Dull?)

by Sherwood Heggen

So many would be excellent wood-workers have one common fault limiting their success. They don’t keep their tools sharp. This is much the same as a person who thinks they take good care of their car and neglect maintenance of the constant wear items such as brakes, shocks, and exhaust system. Have you taken a good look at the cutting edges of your plane blades and chisels lately? In this Gadgets and Kinks, putting a sharp edge on those tools will be the subject.

To many, holding the tool to the spinning surface of a grinding wheel is sufficient to get a sharper edge. Actually, that would only be sufficient for damaging the tool. That method can cause overheating of the edge causing it to loose its temper, will cause an uneven edge and bevel to the tool, and will only shorten the life of a tool that could otherwise be made useful for years to come.

There are many fine articles printed and sources of  information on sharpening tools available for those who seek them out. This article will serve to get the wood-worker interested in a making sharp tool edge with a minimum of equipment and expense. From there, the sky is the limit for investing in equipment for methods to produce the keenest edge possible.

How do you know when a tool needs sharpening? Understand that the face of the tool must have a perfect constant bevel and the back of the tool must be perfectly flat to create a razor sharp edge. Take a close look at the front and back edge the blade of a plane, for instance, to see if the edge as a rounded appearance or if it is nicked. Does the tool allow almost effortless work. If not, it is time to read on and then go put a sharp edge on it.

Some very basic tools are required to put a sharp edge back on a cutting tool that will be satisfactory for the common woodworker/boat restorer. They are a holding jig to maintain a constant bevel angle on the tool being sharpened, a flat surface such as a piece of glass or a cast iron saw table, and wet/dry sandpaper. (Refer to picture #1.)

The holding jig is available at stores that cater to woodworkers. It is a necessary piece of equipment for holding the tool blade at a constant angle to produce correct results. Place the chisel or blade in the jig making sure that is secured squarely in place. Now adjust the angle of the blade so that the face of the bevel on the tool makes full contact with the flat surface. This will preserve the original bevel designed for the tool. Lay a piece of 320 grit wet/dry sandpaper on the flat surface. Proceed to draw the tool across the sandpaper with the edge in trail. Check the progress of the action after a number of passes. The surface of the bevel should have a consistent appearance to its surface as in the picture below. If not, continue to draw the tool across the sandpaper until a consistent surface exists. Then switch to 400 grit paper and continue to draw the tool to produce an even finer edge.

Once satisfied with the effort, it is time to remove the tool from the holding jig to clean up the back side of the tool. A very slight burr will exist from working the bevel side against the sandpaper. Lay the tool’s back side on the 400 grit sandpaper and work it in small circles to clean off the burr. Now, be careful how you handle the tool. It is sharp!

Alignment of the blade in the plane comes next to provide for a square cut. Place the plane on a piece of paper (to protect the blades edge) on a hard, flat surface and place the blade in its holder. The blade edge should rest squarely on the flat surface. Clamp the blade in place according to the devices of the plane. Adjust the depth of the blade for the slightest possible cut and do a trial run on the edge of a piece of wood. Now, can you say, “Wow, that is really something”? You should be able to remove wood shavings thin enough to see through.

This method is very simple, but effective. For the purist, oil stones of different grades, water cooled grinding stones, strops, etc, would be the essential equipment to create the
microscopically perfect edge with which one could do microsurgery. It would be nice to have such a privileged edge on a tool, but isn’t necessary to produce excellent results with our chisels and planes to get through the restoration project at hand.

Keeping a sharp edge takes some understanding of the process of planing. Most woodworkers make the mistake of drawing the plane back with the blade resting on the planed
surface after each cutting pass. As it is drawn back, the backside of the blade is being honed by the abrasive qualities of the wood and the perfect flat edge becomes rounded off. To make the plane sharp again, material must be removed past the rounded portion to bring the edge back. Also, be sure the material you are planing or chiseling has no screws or nails in the path of the cutting edge of the tool that will nick the edge. Pretty basic, but so often overlooked.

Go out into the shop and see what is dull and give this a try. I assure you once you properly sharpen one tool and find out what a difference a real sharp edge makes, you will be
sharpening every tool you have. Here again the phrase of “don’t destroy it; restore it” rings true. Many cutting tools are set aside because the edge is gone. Well, now you know how to take care of that. Enjoy!