False Beats

[Paul S. Larudee]

Jim,

That experiment might tell us something, but would leave a lot of questions
unanswered.  One is the absorbtion/expansion properties of different types of
woods, laminates vs. solids, under tension or not, and the extent to which all of
this is grain related.  Furthermore, the pattern of holes might make a difference
- i.e. how far the wood extends beyond one hole before encountering another hole
or the edge of the object, as in a pin block.  I think that may be what's
happening with action centers - i.e. that the surrounding wood may be freer to
expand than in a pin block or bridge.

In the case of the bushing cloth, the issue is not so much how it reacts to
humidity in isolation but rather in its functional setting - i.e. in a specific
type of enclosed space.  And finally, it is not the amount of expansion per se,
but the amount of force caused by the expansion on the center pin.  I can think
of ways to do all the necessary experiments, but I'd have to put in for a grant.
In the meantime, I'd be interested in the thoughts of anyone who would like to
speculate, or who might know of any work that has actually been done.

Paul

JIMRPT@AOL.COM wrote:

> Paul;
>  Don't "debate" it measure it yourself.  Cut a strip of bushing cloth to an
> accurately measured length say two inches long. Also cut a block of wood to
> any acurately measured dimension, say 1 inch square by  2inches long. In the
> block of wood drill a very precise hole all the way through the block (1 inch
> dimension)  ,
> the hole to be, say, 3/8ths.
>  Next soak both the wool and the wood in the same solution of your
> preference, say 50/50 alcohol and water let the wool and the wood stay in
> this solutuion for say 10 minutes. Take both objects out of the water and set
> them on a non absorbant surface. After both objects are dry enough not to get
> your hands wet when you pick them up measure them, the wool in length, and
> the wood in outside dimensions...also measure the hole you have drilled in
> the wood (you can use the drill bit you drilled the hole with).
>  Finally allow both objects to thoroughly dry, say 24 to 48 hours, and
> measure a second time.
>  Let us know what you find. :-)
> Jim Bryant (FL)