Using a diamond edge saw blade and this easily made sled you can easily cut PCB boards. I have a 10 inch saw, but this 7 1/4 blade works quite nicely.

Step 1: Build the Sled.

The first step is to cut the runner. Cut the width so that it fits just loose enough to slide smoothly. The height should be just short of the height of the groove in your table.
Determine the size of sled you want. I made mine just big enough to be used in either groove. Make it a little bigger than you want the finished size to be.
Glue and screw the runner to the bottom of the sled in approximately the center, At this point it doesn't even have to be exactly square with the sled
Using a wood blade, not the diamond blade. cut the sled to width using both grooves on your table. It is now square with the blade.
This step will determine how square your cuts will be. Glue and screw the sled fence, Be careful to get the fence square with the blade side of the sled.

Step 2: Add a Hold Down.

To make the hold down I used a carriage bolt and wing nut. The plastic piece is part of a pipe hanger I had in the junk box. Anything with a similar shape will do. Counter sink the bolt head into the bottom of the sled so nothing catches on the saw table.

Step 3: All Finished.

You can now cut really small pieces that are square with out danger of damage to yourself or the piece. Don't forget to wear safety goggles and a dust mask.