Terry, I don't think you should dry the board before gluing to the rim. The assumption that the board will shrink is false. After the ribs are glued, the only thing that is going to change with hunidity is the amount of crown. To me, after the crowning process, the board should not be dried again. I think that high temperature MIGHT affect the glue hardness and cause crown collapse (a little at least). So, I would and will just clamp the board to the rim making sure that the humidity conditions are "normal" (if you deal with extremes, you might want to have more or less downbearing). With the Mason that I'm working with these days, the board was glued in using soundboard buttons (someone might tell me if this was original or not). But you could use this to tie the board down for bearing adjustments. Have fun and keep me in touch. We are learning my friend. Marcel Carey pianotech list info: https://www.moypiano.com/resources/#archives
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