I’ve discoverd why my Powermatic 64A contractor saw has made such horrible cuts for the last five years. I thought ‘hey, it’s just a contractor saw its not supposed to do any better’. When I finally got a dial inidcator I found that the blade will not stay parallel to the miter slots. Normal use will slowly vibrate it out of true and tilting the blade immediately takes it way out of whack and it stays out of whack when the blade is set back to vertical. With a dial indicator the blade can be tweaked back to parallel by pulling or pushing on the splitter bar (which is attached to the carriage) after a few tries. Unfortunately this needs to be done often to keep the blade running true.
At first I thought the issue was due to inadequtely tightened bolts that hold the carriage assembly to the underside of the tabel. I tightened to the point of nearly stripping or breaking them but the problem still occurred. I communicated via e-mail with Powermatic tech support and they sent an adjustment procedure that shows how to set the two main rails of the carraige assembly to be parallel and lock them down. This pointed out the real problem. The round rails that connect the front and rear trunnion pieces can rotate and twist under torque. With the blade vertical the motor puts only slight torque on the assembly but at 45deg the weight of the motor twists the carriage rails considerably. Trouble is, regardless of how tight the lock nuts are made the rails still rotate in their holes and take the carriage out of true. When I informed Powermatic of this they suggested I take it to a service center. The service center obviously will not be able to fix this because it is just a poor design. Powermatic does not have a redesigned carriage for this saw. They also would not honor any knid of workmanship guarentee.
I’m wondering if there are other 64A owners out there with similar experience. I’ve designed a fix for this and am testing it. I’d be glad to share it with other dissatisfied 64A owners once I know it works.