Popular Woodworking 2006-12 № 159, страница 41

The housed dovetail is strong and forgiving

A half-blind dovetail is much stronger mechanically than the dado

A dado alone offers little strength and no long-grain-to-long-grain gluing surface

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With the housed joint, even if the tenon is miscut, the gap is easy to hide and the joint is still strong

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With a half-blind dovetail, ifthetenonismiscut, the gapis obvious and thejoint is weakened

Combining a dado joint with a half-blind dovetail yields a superior joint for casework. The weaknesses of both joints are eliminated.

The ³/4" outside-diameter guide bushing must be reduced to protrude less than V8". This allows the base of the router to lay flat on the workpiece.

The first step is to mill all of the dados to a depth of V8" with a ³/4"-diameter straight router bit.

Use the modified guide bushing and a ³/8" straight bit to prepare the socket for cutting the dovetail.

Use the same guide bushing and a ³/4" dovetail bit to finish the dovetailed part of the joint.

Searching for a Solution

As I tried out different methods, I built numerous sleds and edge guides, but my only success required the use of a sled and two matching routers - one fitted with a ³/4" O.D. straight bit, the other with a ³/4"-14° dovetail bit.

My search for a simple solution led me to milling all the dados prior to routing the dovetail sockets. But aligning the dovetail bit with the dado was not possible because a standard ³/4" guide bushing was too deep for the Vs"-deep dado, and the ³/4" dovetail bit interfered with or would shear the guide bushing. Then it occurred to me that what I really needed was a shorter guide bushing.

Get a standard ³/4" O.D. Porter-Cable router-guide bushing and reduce the protruding guide to

slightly less than Vs". You can cut the excess off with a hacksaw, and then file or grind the cut edge smooth.

Now you can set up your router with the modified guide bushing and a ³/4"-14° dovetail bit as seen in the photo at right. The bottom edge of the dovetail bit should protrude a bit less than V2" below the guide bushing, for a total depth of about ⁵/s". Be sure your stock is thick enough to prevent routing through your workpiece. I recommend using ¹³/l6" or %" stock for case sides. The drawing at the top of this page shows the proportions and appearance of the finished housed dovetail.

A Simple Formula

To successfully make the housed dovetail joint there are a few mill-

As you slide the router along the edge, the guide bushing and dovetail bit will enter the dado together.

ing, tooling and setup requirements. The dado must be a minimum width of ³/4" to allow a ³/4" guide bushing to ride into the dado to create the dovetail socket. The dados should be slightly more

than the depth of your modified guide bushing. The stock thickness for the drawer dividers or shelves should be the same as the width of your dados.

After milling all the dados with

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Popular Woodworking December 2006