Making a diagonal cut using a crosscut sled

How do you safely cut diagonals on the table saw?

I'm making a 12"-wide shelf 6' long. I want to make shelf supports out of 12" x 12" pieces of 3/4" plywood. How can I safely cut the 12" x 12" from corner to corner to get two right angle supports?

Chris Marshall: A diagonal cut like that would be easy to do on a crosscut sled at your table saw. If you don't have a crosscut sled, this might be a great opportunity to get or make one — you'll use it again and again. In terms of the squares you want to cut, I'd just apply a few pieces of double-sided tape to the bed of my crosscut sled, stick the squares down to them with the diagonal corners of the plywood (along the cutting line) aligned with the blade opening on the sled, and make the cuts. It will be simple and safe. The tape will hold the workpieces securely, but make sure the bed of your sled is clean and dust-free before sticking down the tape for best adhesion. If you don't have much experience with double-sided tape, the stuff holds tenaciously well.

Tim Inman: There are any number of ways to do this safely. I really like using a sled on my table saw top for cuts like this. My father would scoff at this question and just get out his trusty miter gauge and run 'em through. Then he'd grin at you and say, "Like that." Sometimes his practices make me go outside for a "walk" ... Fastening a sacrificial extension board to your miter gauge would make for better support and a safer cut.