router bits

I have a dodo wiz to make dados and grooves, and I gnerally use a down spiral bit. Very clean cutting, and that jig does such exact width dados that I slip in a piece of paper when setting it up so there's room for glue. I far prefer using this setup with a straight edge. I think someone else bought out DadoWiz and sells it under a different name, the DadoMax. Far easier than all that fiddling with dado stacks. Just don't lift the bit free until it is completely stopped.

The picture shows the straight edge and how you set the exact width by setting a piece of your stock between two stops.