I have made dadoes on a table saw and a radial arm saw for a long time. In the last year or two I started making dadoes with a router but unless you have a bit which is the EXACT thickness of the wood this can get a little tricky. That is what this jig simplifies. I'll be able to easily and quickly make dadoes anywhere from 3/8 of an inch wide all the way up to over and inch and a half.