On Thu, 2 Jun 2005 15:55:09 +0000 (UTC), Dave Chamberlain
wrote:

My son has been getting more and more interested in wood working. He's
in 9th grade and has been getting pretty good at using the scroll saw

Some years ago, I had a pile of thick ivy (4" diameter) and a friend had
a new scrollsaw. So we made lots of things from the pair, including
"Slide-apart ring" on this page
http://www.jarkman.co.uk/catalog/jewel/index.htm

The same idea works for all sorts of puzzle boxes - you just saw out
progressively larger "keyholes" from the piece, starting with the
smallest and first to open, then turning it round 90° between them - I
think one puzzle had seven parts.