After the notches are cut in the bridge tops to the height for proper bearing, the remaining wood must be planed and sanded. Since the board and bridges were dry fitted, I can remove them and do the final work on the bench. (Some rebuilders do all this after the bridges and board are glued into the piano. That requires you to be at some very awkward positions, which my body doesn't do any more!)
I start with a power planer. This requires a lot of care as the machine takes off a lot of material in a hurry. I follow that with a small power sander with 60 grit paper. Again care must be taken. It is very easy to end up with a rounded top, rather than the desired flat top on the bridge with this machine. I finally finish with hand sanding, doing 100, 120, 150 and finishing with 220 paper. Again, care must be taken to keep the bridge top flat. I check this with a straight edge while sanding.
When the sanding is completed, I use my indexing holes to locate the patterns that were made earlier, and mark with pencil all the pin locations. Then the bridge is again dry fitted to the board and piano, and the plate installed. Now I can check that I am satisfied with my bearing, and can also check the bridge pin locations.
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