Popular Woodworking 2003-12 № 138, страница 33

Unlock the 'Keys'

A reinforcement I like for frame miters is the key, either a spline or a dovetail, to add a subtle embellishment to the joint.

Make sure you cut a slot for the key after the joint is glued. For a deep slot - one cut into a wide frame - you can make it on the table saw, while you can cut a shallow slot using your the router table.

The jig shown at right works on either the table saw or the router table. On the latter, you can use it by sliding it along the fence to cut with a bit or by sliding it across the tabletop to cut with a slot cutter.

This approach enables you to use a dovetail key, but the table saw can make a much-deeper cut, which is important for frames that have wide members.

Construction should be evident from the drawing. Miter the ends of the two frame supports, then glue and screw them to the plywood back. These supports must be at right angles to each other. In this form, it can be used flat on the tabletop. If you use the jig upright braced against the fence, add the fence hook (seen in the photo at right) to it.

However you orient the jig, the frame is set into it. You can hold it tight with a spring clamp or two. Position the jig and frame against the fence and make the cut.

When using splines, you should make the cuts on the table saw. Rip strips of stock - a contrasting wood is preferred - to the appropriate thickness. If necessary, plane them to fit. Crosscut the strips into little triangles and glue one into each slot. When the glue dries, trim them flush.

Dovetail keys are easiest to cut on a router table. After slotting the frame, cut the keys using the same bit and height setting. The only change in setup is to swing the fence over the bit, housing most of it. Start with an oversized pin and methodically trim it to fit the slot. When you've got a good fit, rip the pin from the board. Repeat the process until you have enough key stock. Then you can simply cut the stock into short keys and glue a key into each slot.

When the glue dries, the keys must be trimmed flush. Saw off the keys as close as possible, then trim the remaining stubs flush with a block plane (work from the corner in, so you don't tear out splinters of the keys) or sand the stubs flush. PW

You can cut slots for spline keys on the table saw.A shop-made jig that straddles the rip fence holds the assembled frame.

You can cut slots for dovetail keys on the router table using the same type of jig. The slot can be centered easily by turning the frame around in the jig after the initial cut, then making a second pass.

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