Ideally, joints should be sawed in concrete slabs before drying or cooling causes random cracking. The 1988 introduction of the Soff-Cut early-entry saw made this possible. The electrically powered saw permitted joint cutting with a 5-inch-diameter blade as soon as the slab could support the weight of the operator and the machine without disturbing the finish. The contractor who invented it sought the help of some younger workers—hence it's not surprising that the design started as a saw mounted on a skate board with a stick affixed to the back. If you don't want to take your tux onto the concrete, you can use the extension handle (photo March 1988).