1 Building the jig
 |
Easy to assemble, the fence-straddling jig shown at right works well for cutting two-shouldered open mortise-and-tenon joints. Refer to the dimensions suggested in the illustration, making sure the thickness of the spacer and width of the brace allow the jig to slide smoothly along your rip fence without wobbling. Cut the body and brace from Winch plywood and the guide and spacer from solid wood. Saw an oval hole for a handle in one corner of the jig body and attach the guide to the body directly in front of the handle hole, making sure that the guide is perfectly vertical. (The blade may notch the bottom of the guide the first time you use the jig.) Screw a small wood block to the body below the handle and attach a toggle clamp to the block. Finally, fasten the spacer and brace in place.
 |
 |
 |
 |
|
1 |
Assembling the jig
The jig shown above can be used on the table saw to cut both parts of an open mortise-and-tenon joint. Refer to the illustration for suggested dimensions. Cut the jig fence and back from three pieces of %-inch plywood and saw a 45° bevel at one end of each board; the pieces should be wider than the height of your saw’s rip fence. Fasten two pieces together face-to-face to fashion the back, then use countersunk screws to attach the fence and back together in an L shape; make sure the fasteners will not be in the blade’s path when you use the jig (inset). Next, cut the brace from solid stock, bevel its ends and attach it along the top edges of the fence and back, forming a triangle. Cut the runner from solid wood and attach it to the fence so that the jig runs smoothly across the table without wobbling. (The runner in this illustration has been notched to fit the particular design of the saw’s rip fence.) Finally, cut a piece of clear plastic as a blade guard and screw it to the jig back flush with its front face.
ШШШ11Ш11ІІ
SHOP TIP
|
3 |
Cutting a tenon
Set the jig on the saw table in front of the blade with the runner and fence straddling the rip fence. Secure the workpiece in the jig by turning the eccentric clamp, and position the rip fence so that the blade is in line with a tenon cheek cutting mark on the workpiece. Feed the jig into the blade. (Your first use of the jig will produce a kerf in the back.) Flip the workpiece in the jig and repeat to cut the other cheek (above). Remove the jig from the table, lower the cutting height to the level of the shoulders, and shift the rip fence to cut the tenon shoulders.
|
|
|
