A simple crosscut sled is the key
A table saw crosscut sled jig is a simple solution to the problems associated with making medallions, parquet tiles and borders. The crosscut sled helps keep fingers away from the table saw blade and make very accurate repeatable cuts.
A crosscut sled is a table that slides across the top of your table saw. This table can actually be just a piece of plywood or MDF. It has two runners on the bottom which fit into the miter slot on the top of the table saw. A fence is a board that the pieces being cut rest against. This simple fence is attached to the sled and adjusted to the table saw blade for the angle desired.
My sled was made from a used piece of birch plywood and the cut off waste from a stair tread. The runners were cut from a piece of oak strip flooring. I applied a coat of polyurethane to the sled to help prevent it from distorting from moisture over time.
To make your sled, find a piece of thick plywood about the about the same size as the top the table saw. It is great if you can find a piece of nine ply Baltic birch which is very stable plywood. The sled requires two runners which align the plywood to the table saw blade.
The runners that I made were cut from a straight piece of plain sawn oak floor. The strip flooring boards are thick which fit great in the miter slots of the table saw Trim the runner material on the table saw to the correct thickness if need be. The thickness of the runner should be less than the depth of the miter slot. The _" thick oak flooring had grooves on the back of the board. The groove areas were not used. The runners were made from a plain sawn board but due to the way it was cut, it ended up being quarter sawn. This means the runner will not expand and contract very much with moisture changes. If the width of the runners did change, they would jam or be too loose as the humidity in work area changes.
I do appreciate beautiful jigs built by master craftsman but even better are simple jigs that build beautiful things. Our simple table saw sled is easy to manufacture but is capable of making floors worthy of a palace. Start, by protecting the top of the table saw with kitchen plastic wrap. Place your runners in the miter slots and shim them so their top surfaces are flush or slightly above the top of the table saw. Apply wood glue to the top of the runners and set the plywood on top. I use five minute epoxy. When the glue dries, get rid of the plastic wrap. Clean up any excess glue. The table saw sled runners should slide across the top easily. Waxing the runners will aid them in sliding. I like to counter sink a few screws into each runner to help hold them in place.
The sled requires some sort of fence to position the pieces of wood during cutting. A board attached to the front of the sled will act as a stiffener and a fence. A second board attached to the rear of the sled is used to keep the plywood base rigid. In other words it keeps the sled from splitting in half after being cut. Attach the rear stiffener board first. This stiffener only needs to be about a half as wide as the sled. Any longer, and the sled will be able to cut only short pieces but still would work for our project. Alignment is not critical. Attach it using wood glue and screws.
The alignment of the forward stiffener board is critical if it is used as a fence. Place the sled on the table saw and cut 2/3 the way across the length of the sleds plywood base. Turn off the table saw and lower the saw blade. Use your carpenter square to align a temporary board perpendicular to the blade cut. Lay the temporary board flat on the forward end of the sled. Leave enough room to attach the fence board. Then, screw down one end. Slowly, adjust the other end until it is perfectly square with the saw blade cut and finish fastening. Use the temporary board to align the fence. Attach the fence using wood glue and screws and remove the temporary board. After the front and back stiffeners are firmly attached, the table saw blade may cut the rest of the way through the sleds plywood base.
Many parquet patterns and medallions are composed of pieces of wood cut at 45 degrees and 90 degrees angles. Our sled is all set to cut our 90 degree cuts. Another board will have to be attached to the sled to cut the pieces at 45 degrees. Two common speed squares can be used to set the secondary fence to an angle of 45 degrees relative to the saw blade. A few screws are used to secure the secondary fence to the sled.
Remember, the crosscut sled will help keep fingers away from the table saw blade and is capable of making very accurate repeatable cuts. The sled can be made from scraps and the most critical point is to align the fences to the saw blade. Your sleds can become more sophisticated and grow with your skill level.