Old Craftsman Table Saw Additional Load as Blade is Raised
Is this one of the old Sears models where the motor hangs off the back on a hinge? The weight of the motor supplies the tension. It is possible that the hinge is frozen allowing the belt to over tension. Ideally the motor should be free to move as the blade is raised and lowered. The pivot bolt should be tight enough to prevent lateral movement (left to right). It should be loose enough that you can raise the motor by hand. The belt tension is determined by the weight of the motor. I have seen people even hang scrap metal (window weights were popular) on to the motor to increase tension as the belt ages and begins to slip under load.