Single Skill Subject: "Table Saw Dados and Rabbets"

I find that I take some things for granted, and I do until a reader asks a question, and then I go to the shop in search of the answer.    This week the question was "how do you cut clean dados in cheap plywood and white melamine particle board?"    This picture is of the new CMT dado set. My set is similar but has chippers with fewer teeth. But it will give me a chance to make some dados and see how good they are. I am sure I have some plywood and white melamine boards around.
	Joslyn and I start the test by cleaning the blades. We use them all the time and dirt and resin builds up without you really knowing. She uses a spray bottle of CMT Formula 2050 Blade and Bit Cleaner. It is great stuff. Jos just sprays it on and lets it sit for a minute or two.
The orange coating makes for a pretty blade, but it has a real useful function as well. It is a Teflon® coating which makes it better able to make clean cuts time after time. It also makes it easier to clean when that time comes.
	This is a close-up of the  teeth with some cleaner on. It shows resin on the edges of the tooth and dirt in between the cutter.
The cleaner does a great job loosening the dirt and burnt-on resin. Jos uses a small brass brush to cleanout the gullets and the sides of the teeth.
	Joslyn cleans the black chipper blades as well. The new CMT dado sets have improved chippers — with more teeth for even smoother dado bottoms.
The newly cleaned blades are now ready for use. We are going to make a number of dado cuts, Joslyn starts out by installing the two outer blades on the spindle. This will give her a dado that is 1/4" wide.
	We will take the time to make zero clearance plates for each of the combinations of blades and chipper sets.    Joslyn lowers a blank plate so that she can raise the spinning blades through the wood insert.
Joslyn has moved the fence so that it is just holding down the plate and raises the blade slowly keeping to the right of the fence so that if the plate came loose, she would not be in the line of fire.
	The arrow points to the fence that is overlapping the insert plate. You can see from this view that the "zero insert" should give great cuts.
Several blade combinations later and Joslyn makes the cut. She has carefully set the blade height to 3/8" — a typical depth for dados in 3/4" stock.    She is using the Grr-ripper to hold the workpiece down over the blade, and she uses her left hand to keep the piece against the fence. She keeps her body angled behind the fence so that she is not in harm's way.
	Here are the cuts she made with the full dado set with chippers to make a 3/4" cut.  Joslyn made two cuts in the piece of "cheap" birch plywood. There was no tearout or roughness in the bottoms of the dados. Same with the white melamine particle core board — beautiful clean cuts and a smooth groove. Just think of the beautiful, finished dados she would have when plowing cabinet grade plywood and real wood.    I thought we had been creating good dados — now I am sure of it.