Simple to build and use, but very capable. Click image to enlarge

Auto-Width Dado Jig - NWW011

An easy way to route accurate dados

Difficulty: New Woodworker & Up
Text and photos by Tom Hintz

   This jig evolved from one a woodworking neighbor of mine was trying to develop 15 years ago. I moved away before and never heard if he perfected the idea, but the concept stayed with me. Over the years, I made several variations of that first jig, eventually settling on the one described here.

   This version of the Auto-Width Dado Jig is easy to use, handles a wide range of wood sizes and has additional capabilities that make it even more valuable in the average shop. What makes this jig especially useful to so many woodworkers is it needs only a standard hand-held router equipped with a straight ½", flat-bottomed bit. No bushings, edge guides, special baseplates or other fixtures.

Simplicity Is the Answer

Straight dados, non-parallel or angled, this jig does them all, without measuring stock width. Click images to enlarge

   While the basic design of this jig has not changed drastically, a series of small improvements made it more effective, and easier to use.

   Dados from ½" to 7 ¾" in width (and bigger by moving the jig) with a side-to-side limitation of nearly 25" means most dado jobs can be handled with this one jig. This capacity makes it possible to cut angled dados and even half-lap joints in steeply angled X-braces.

   When routing dados in large stock, the jig can be clamped directly to that material. If the stock being dado'd is small, the jig can be clamped to a table (with spacers under each end to make room for the clamps) and the work piece clamped directly to the jig.

No Measuring

   The moveable bar assembly eliminates the need for measuring the wood and specially sized bits. Mark a line where the dado should start, align the fixed bar

Even half-lapping an X-brace is easy with this jig! Click image to enlarge

with that line, hold a sample of the stock that will fit into the dado against the fixed bar, snug the moveable bar against it and tighten the locking knobs. That's it, set your router bit depth and route a perfect dado. If there are several dados of the same size to be made, simply move the jig to the new location, align it with the layout line, clamp and route.

   This jig also can cut dados with non-parallel edges. I understand these are very rare, but consider how this capability allows you to dress up a project with a tapered brace or sidepiece cleanly dado'd into the legs or uprights.

   The Auto-Width Dado Jig can be built to use virtually any size router bit, but that bit must always be used with that jig to retain the accuracy. This is a very cheap jig to build, so if you need more than one size bit, build another jig! The plans require no other adjustments after the sizing described in Step 1.

   Included in the NewWoodworker.com Plan Set are complete step-by-step instructions for building and using the Auto-Width Dado Jig, and a link to a special page on NewWoodworker.com with photos to further support the instructions.

Order your Auto-Width Dado Jig Plan Set for only $2.95!

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