Sharpening a non-piloted router bit
Use a benchstone to hone the inside faces of the cutting edges of a high-speed steel bit, like the one shown above. Holding the inside face of one cutting edge flat against the abrasive surface, rub it back and forth. Repeat with the other edge. Hone both faces equally to maintain the balance of the bit.
Sharpening a piloted bit
Remove the pilot bearing (page 26), then sharpen the bit as you would a non-piloted bit (page 32). For a carbide-tipped cutter like the one shown above, use a diamond sharpening file. Reinstall the bearing. If it does not rotate smoothly, spray a little bearing lubricant on it. If the bearing is worn out or damaged, replace it.
The cutting edges of router bits, particularly those made of carbide, can be nicked if they are thrown together in storage. Protect your bits with a simple shop-made rack. Make the rack with your table saw, cutting four stepped rabbets along the edges of a 4-inch-thick and 8-inch-wide board that is long enough to accommodate all your bits. Outline the two outside rabbets on one end of the board so the width of each rabbet is about one-fifth the board width. The rabbet depth should be about two-thirds the stock thickness. Cut the rabbet shoulders with the stock face-down on the saw table and the edge riding along the rip fence. Use a feather – board to support the stock as you cut the rabbet cheeks. Shim the feather – board with a board set on edge and brace it with a support board so that it will press against the middle of the workpiece and minimize wobbling. Once you have cut the two outside rabbets, outline the two inside ones, making them the same width as the first two, but only one-half as deep. Saw the rabbet shoulders first, then cut the cheeks, feeding the bottom face of the stock along the fence, with the edge flat on the table (right, above). Then drill a series of holes the size of the bit shanks on the rabbeted face of the rack to hold the cutters (right, below).