I'm not too sure about the moisture absorbing qualities of wood but I think
the main reasons wood was used to package precision tools in the olden times
is that it was very much available cheaply and is a softer material that
won't mar the tools, rather than for its moisture absorbing qualities. Wood
is still being employed today for its traditional and aesthetic appearance
but plastics are also becoming very common.

"LowEnergyParticle" wrote in message
ups.com...
| Measuring tools and instruments often come in wooden cases. I've seen
| mahogany, birch, poplar, pine, and several other woods used. The idea
| is that the case will absorb moisture from the tool and thereby keep
| it from rusting. Usually, these boxes are finished with a varnish on
| the outside, and less often, on the inside. When the inside is not
| varnished, it is usually left bare. I'm reasonably sure the original
| finish is a varnish, because I've tested for shellac with denatured
| alcohol, and these boxes generally predate polyurethane.
|
| When I buy a used instrument the box is often in rough condition, and
| I like to put them back in good shape by regluing, sanding, etc. I've
| been leaving the inside sanded but unfinished (no coating of any kind)
| and spraying polyurethane on the outside.
|
| 1) to maximize the water absorbtion, should the inside of the boxes
| be left unfinished?
| 2) to maximize the water absorbtion, should the outside of the boxes
| be left unfinished?
| 3) Is clear gloss sprayed polyurethane a good choice for finishing,
| given that the water absorbtion issue is much more important than
| protecting the finish of the box?
| 4) For making a new box from scratch, what wood choice would maximize
| the water absorbtion?
| 5) I've seen some pretty old tools with ground cast iron faces arrive
| inside intact boxes without rust, so I'm kind of tempted to believe
| the whole water absorbtion idea. If anyone can substantiate this
| theory, or offer an alternative hypothesis, I'd be very grateful.
|
| I've cross-posted to our brethern over in rec.woodworking since they
| have specialized knowledge of woods, as well as a shared deeply-held
| hatred of rust on tools!
|
| Thanks very much!
| Dave
|