When humidity has been high, things swell up and become tighter, lost motion decreases When things dry out, they shrink, lost motion increases. I work in the Ottawa valley, Canada. Here the change can be dramatic. We can get up to100 degree heat and 100% humidity come July. We can have 50 below zero in January, and temp. may not exceed 20 below zero for over a week at a time. Furnaces work overtime, pianos become dry & increasingly flat through the tenor area. I remember one of my earlier regulations, at the end of a long winter. The lost motion was perfect. I was called back in the summer and all the hammers were riding compleatly off the hammer rail. Allot. Parts had absorbed some moisture and expanded. So in the middle of summer I do lost motion as tight as possible, but allowing so the jack will still return properly. In the driest months of winter here, I allow a little bit of lost motion to creep in. Not much, and keep it even. This depends in part on how often I will see the client, and how much I trust the piano to be stable. Some pianos seem more stable. I assume due to the quality/density of the felt & cloth. Is that so? Is the reason some instruments fair better then others due to the density/quality of the felt & cloth. Perhaps it's just geometry. Perhaps humidity changes in smaller parts have a more profound accumulative effect? Anybody? David Renaud RPT Canada Clyde Hollinger wrote: > Friends, > What happens to lost motion, particularly in spinets and consoles, when > the humidity changes? When does it increase or decrease, and why? > Regards, > Clyde
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