Raise blade to full height, and place a piece of freshly jointed wood next to blade on on right side, contacting teeth both front and rear. Using dial indicator, check both front and rear measurements from left miter slot, and verify that they are the same. If you don't have a jointer, then use an aluminum level instead of wood. Blades are often made so as to have a dish at rest, but centrifical force pulls them straight. On higher quality blades, you can often see a tension ring that does the same thing. After you rip a piece (not forcing it against the fence,) check it over it's length and see if it's straight. The outer and inner arbor flanges should be dead flat with each other. Just some random thoughts, which you can, with sixty eight cents get a senior coffee at Mickey D's. Just make sure you have the sixty eight cents.