Dado Setup Jig

When making a series of matching dadoes, it's important that the two shoulder cuts align perfectly to the blade. Here's a simple jig you can build to keep your dadoes aligned and accurate.

he jig is a small adjustable hardboard stop attached to a clamping block with carriage bolts and nuts. By adjusting the nuts, you can move the stop in or out to register the cut for the inside shoulder without having to reset the fence between cuts.

Here's how to set up the jig.

First clamp the jig to your fence (Fig.1).

Then mark the dado locations on your workpiece (Detail a) and posi-tion it against your fence so that the dado blade aligns perfectly with the inside shoulder of the dado.

Now, before making any cuts, reposition the workpiece and adjust the hardboard stop so that it aligns perfectly with the outside shoulder of the dado.

Once the jig is set up, you're ready start cutting (Fig. 2). Make the first cut with the end of your board butted against the fence to define the inside shoulder of the dado.

To make the second cut, slide the board away from the blade and butt the same end against the hardboard stop. This defines the outside shoulder of the dado. To complete the dado, clear away the waste between the two shoulder cuts.