>Ron & the list, > >as anyone measured this bridge pin "heave" with a height micrometer? I >suppose it would do as well to measure the change in the height of the >bridge from the soundboard and the change in the crown. I'm going to run a >few of these measurements myself but it may take me a while to come up with >some good empirical answers. I have another question on mensuration but >I'll stick tat in a separate post. > >Allan Did that and posted it. I recently ran a test on a sample bridge section to see what happens to bridge pin height during humidity swings. Cooked in a fishing rod case with a DC heater rod for three days, the average pin height above the bridge cap measured 0.126". After three days in a plastic container with an open bowl of water, average pin height was 0.117". At the same time the pin height went from 0.126" > 0.117", the bridge height went from 1.091"< 1.119". But the pin doesn't come out of the bridge. It's still tight at the bottom and doesn't move relative to the wood there. Crown changes don't figure in. I think tapping pins down "works" better than tapping strings because, like Roger said, the string is dragged down onto the bridge edge. if the pin groove isn't buried in the bridge by the process, it helps hold the string down. It probably helps to crush the cap more with the next wet cycle too. If the groove is buried in the bridge, the bin is left resting on new pin surface, which also seems to help. Playing with a rebuild job before teardown one afternoon, I tried a few things on false beaters and found that just turning the pins a few degrees without driving them in or tapping strings at all cleared up about as many false beats as tapping strings did. Our current bridge pinning system is obviously not the ideal way to couple a string to a bridge. Ron N
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