Yes the 6" Rafter Square locks and loads every day but it's always needed for my big dicks I was planning to to build a porch with a 12 inch screen, so the opportunity presented itself. I was late with my order but was happy to see my square arrived at the same time as the wood was delivered to work. So the work went smoothly and all corners were without problems. Most of the time I cut with a circular saw and a square as a guide. And it allows you to get the job done quickly, whether it's docking knots, cutting decking, or cutting roofing.