Popular Woodworking 2007-08 № 163, страница 52
Guided by the kerf. One precise cut establishes the size of the tenon. This L-shaped jig attached to the miter gauge is simple and safe. Form and function. The first template generates the shape of the ends and the through mortises. The oak blank below it is cut 1/16" oversize, and the holes minimize the work for the router bit. it yourself. Before cutting the outer shape, lay out and make the mortises. There are many possible ways to make the mortises. I used a 5/8"-diameter straight bit in a plunge router, guided by the router's fence. With the pattern blank firmly clamped to my bench I plunged the router within my layout lines to make the cut. Make the Templates The advantage of the router is that it removes a lot of material quickly, making smooth mortises with parallel sides. The disadvantage is that it can't make a mortise with square ends. But two hand tools - the chisel and the rasp - solve this problem quickly. First on the template and then on the real parts. Because I had to square the rounded ends of the mortise slots by hand, I didn't bother setting any stops for the ends of the mortises. I did it by eye, starting and stopping about 1//16" inside the lines. After chopping away most of the waste in the corners with the chisel, finish the mortises with a rasp. With those done, cut the outer shape ofthe pattern with the band saw or jigsaw, and smooth the perimeter with the rasp before adding the stops as seen in the photo above. A dab of glue and a couple 23-gauge pins hold the stops in place. The shelftemplate is made from the template for the ends. Line up one edge of the shelf pattern blank to the end of one of the mortises in the other template and transfer mortise locations. The 3/8" offset in the shelf pattern allows space for the edge that will be added to the back of the shelf after the bookrack is assembled. Make the cuts that define the edges of the tenons on the table saw, as seen in the photo Nothing to chance. The saw kerf in the horizontal part of the jig shows exactly where the blade will cut. With the layout line at the kerf line, clamp the piece to the jig. above. To do this, screw a couple pieces of scrap together in an "L" shape and attach that to the miter gauge of the table saw. This provides a reference for where the blade will be during the cut. Clamp the shelf pattern to the miter gauge attachment to hold it in position and to keep your hands a safe distance from the blade during the cut. To remove the waste between the tenons, make a rough cut on the waste side of the layout lines at the band saw then clamp a straight piece of plywood directly on the line. Then, with a flush-cutting bit in a router, trim the pattern back to the line and clean up the corners with a chisel. The goal at this point is to get the tenons on the shelf pattern to fit in width in the mortises of the end pattern, as seen at right. When pattern-trimming mortises in solid wood parts like this, I always use the smallest diameter router bit available. This minimizes the curved waste left in the inside corners. I use the patterns to trace the shapes on the wood. I keep close to, butjust outside the lines to reduce the material the router will remove. Then I cut all the parts to rough sizes. Good Reason to Go Backward Hogging off a lot of solid wood is an invitation to chipping or tearing out the solid wood, particularly on the curves. Clamp the patterns and the parts securely to your bench and make the first pass moving the router counterclock- Get this right and success will follow. Take time to fit the tenons in the shelf template to the mortises in the end pattern. When the parts are routed to the templates, the joints will work. wise around the outside of the pattern. Climb cutting in this way helps to reduce chipping and tear-out. Drill two holes at the mortise locations to allow the bearing on the bit to reach the pattern below. After routing the mortises, the corners have to be squared. I use a chisel and put the back against the end-grain edge of the straight part of the mortise. Holding the chisel flush, swing the corner down to establish a straight line. Turn the chisel 90° to set the perpendicular line at the end of the mortise. Then, go back to popularwoodworking.com ■ 61 |
