There are some of these safe cutting straightedges on the market but they cost as much as $60 for one very similar to the one we are going to make here. I have had these safety straightedges way before they went to market, as I have been doing this type of work for over 30 years.
You will be able to make one of these for under ten bucks with plenty of materials left over for more projects we will be making.
Materials you need:
An aluminum yard stick (you might look for one wider than the one in the demo here, but it works)
A piece of aluminum angle (1/2 X 1/2 X 1/16 thick)
Some heavy duty carpet tape
A piece of rubberized tool box liner
Tools you need:
Small miter box (or big one if you have it)
End view of finished safety straightedge: