hello I bought a used dewalt planer and have had nothing but problems. I needed to turn the blades and the screws were so tight but the first blade worked but once I got to the second there was one screw that stripped so I went to the second and yet again another screw got stripped. how on earth do I fix this? please help I have an order for a large custom built rustic table made from 2 x 8 and I cannot get the top flat with the boards I am using as I only build from reclaimed wood. perhaps another solution to a flat top would help. thanks