Popular Woodworking 2002-08 № 129, страница 38
Drawboring is an easy way to make a heavy-duty joint. Begin by drilling a 3/sM-diameter hole through the mortise as shown above. Now clamp the tenon into the mortise and mark the center point of the hole using a drill bit and a mallet (right). Now drill a hole in the tenon that's V32" in toward the shoulder from the mark you just made. Drawboring the tenons on the end rails Drawboring Explained Before glues were as reliable as they are today, 18th-century craftsmen would "drawbore" a mortise-and-tenon joint to get a more mechanical fit. It's not at all difficult to do and reduces the chance of having a gap in your joint, too. The key to a drawbored joint is a wooden peg or dowel that pulls the tenon into the mortise. Begin by drilling a 3/s"-diameter hole for the peg through the mortise only, as shown in the photo above. The hole should be located 1/2" from the edge of the leg and go just a little deeper than the wall of the mortise. Now assemble the joint without glue and clamp it up. Take a 3/s"-diameter brad-point bit and place it in the hole you just drilled. Use a mallet to lightly strike the bit to mark the center of the hole on the tenon's cheek. Remove the tenon and make a mark for a hole through the tenon that's in the same location as the mark you just made but 1/32" closer to the tenon's shoulder as shown in the illustration at right. Drill a 3/s" -diameter hole Once you've drilled the counterbore and the through-hole for the bench bolt, mark its location on the end of the tenon using a brad-point bit. 11/8" counterbore — J/2" x 6" clearance hole for bench bolt 3V2"- -1" - diameter hole for brass nut Rail 3/4" x 3/4" x 63/8" tenon Bench bolt 1/2% Leg 37 |
