A speed square is an extremely useful carpenter’s tool that is used to make basic measurements and mark lines on lumber. It may be called a square but it’s really more of a triangle. Regardless, this tool can also act as a saw guide to make short 45 and 90 degree cuts. The 1st video will show you everything that you need to know to get around your speed square.
2nd video will show you some tips and tricks that have been picked up through experience and experimentation.