Cutting a perfect dado without measuring by using a "DOG" board.

This technique is best used when you are only making a few dados. When making many dados it will be quicker to set up your dado blade. This technique uses a standard table saw blade. The blade should have some or all flat teeth to ensure a flat bottom on the dado.

A dog board is a board that is ripped so that its width is equal to the desired width of the dado minus the width of the sawblade.

Making a dog board.
1. Rip a piece of hardwood that is about the length of you fence.
2. Without moving the fence, place a piece of the wood that will go into the dado right up against the fence with the edge of the wood down.
3. Rip the hardwood board again.
4. The cutoff is your Dog Board. Mark the “top” of the Dog Board.

Using the Dog Board.
1. Set your saw blade to the correct height for the dado.
2. Set your fence to cut the edge of the dado that is furtherest away from the fence.
3. Make the first cut.
4. Place your Dog Board between the fence and the piece to be dadoed.
5. Make the second cut.
6. Remove the Dog Board and then align your fence to remove the material between the two cuts.

You should now have a perfect dado.

I found this information quite a few years ago in some magazine. I don’t know which magazine.

-- "A goal without a plan is a wish."