---------------------- multipart/alternative attachment I think what Dan is trying to describe to you is simply that if the "hole" wasnt there... then what would happen to the same area of wood around that hole ? Why should that react differently, or why shouldnt it ? Think about that as well when you drill your test piece tommorrow. :) In returning a bit to the starting point for this thread, it seems we have reached a consensus that this problem about keybeds and lost motion is probably more related to felt being affected by humidity changes then to wood related concerns ?? Farrell wrote: > Your position is consistent with many others. It is likely I > who is hard/thick headed. I just may go out to the shop > tomorrow morning and drill me a hole in some maple and see what > happens. Just does not make sense to me. :-) I'll report > back! Terry Farrell > Piano Tuning & Service > Tampa, Florida > mfarrel2@tampabay.rr.com > > ----- Original Message ----- > From: Donald Mannino > To: pianotech@ptg.org > Sent: Monday, January 01, 2001 10:56 PM > Subject: Re: moisture in wool or wood. > Terry Farrell wrote: > > > I have heard/read this many times, so I suppose it > > is true. But, intuitively, it makes no sense to me. > > If you drill a hole in a piece of wood and expose > > it to high humidity, the wood will swell - and > > swell much more across the grain (perpendicular to > > the grain direction) than with the grain. So why > > doesn't the hole tend to close a bit - on the two > > sides of the whole where the tangents are parallel > > to the wood grain. > > > Because the whole piece of wood swells, and the hole > becomes larger along with the piece of wood. As I > wrote in my last post, imagine the plug of wood which > used to be in the hole. The hole behaves the same as > the plug of wood that was taken out. > > Do the hole and rod test. Just pick a small piece > of maple or something, soak it in water for a while, > then drill a hole in it with a spare drill. After > drilling, put the drill back in the hole, then dry > the wood in the oven! That drill will be really > nasty tight in the hole! You'll have to soak the > wood again to get it out. > > There are some exceptions to this behavior: > 1. In some situations the surface fiber swelling in > the hole exceeds the change in shape of the wood. > Key balance holes are examples of this, where high > humidity sometimes tightens the fit. The wood > thickness is small, and the wood fibers are large and > sometimes made of more reactive wood. > 2. Cross-laminated wood is more dimensionally stable, > and the surface fibers will again have more affect on > the hole size than the dimensional changes of the > wood. This is what happens in pinblocks. > 3. If the hole was made by compression of the fibers > instead of by drilling and removing wood (like with a > nail) then the grip on the nail is tighter during > humid times. All surface fiber effect, no hole to > swell. > > Don Mannino RPT > > -- Richard Brekne RPT, N.P.T.F. Bergen, Norway mailto:Richard.Brekne@grieg.uib.no ---------------------- multipart/alternative attachment An HTML attachment was scrubbed... URL: https://www.moypiano.com/ptg/pianotech.php/attachments/73/63/3e/d0/attachment.htm ---------------------- multipart/alternative attachment--
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