About 10 Years ago I bought the above planer. Aside from the two sets of blades that came with the machine, I purchased two more sets. Well after many years and many sharpenings, I find that the JACK screw will no longer reach the bottom of the blade. Question?? Are there longer JACK screws or do blades have a sharpening limit. There is still plenty of HSS showing on the blade. I measured the width 0.762 down from the original !.0". If they are used up, does any one know of a good source. JET's price has nearly doubled from the original price. THANK YOU! insteadof.