Hey DJ.. To me the most important consideration is expansion and
contraction of that hardwood top. The center section will expand and
contract across the grain towards the chair and as it does so the mitered
joints between the top sections will expand and contract a bit also... much
like any other mitered joint if it is not securely connected to the
adjoining part in some manner. If you simple use a lap joint and do not
fasten the pieces together, I'm pretty sure the seam will open with change
in humidity and season. To me, it seems necessary to securely connect the
top pieces together so this won't happen. Draw bolts with biscuits for
alignment as you suggested sounds to me like a very good way to accomplish
that. Basically you then have one tabletop and not three pieces. Since its
solid wood you can't just screw base cabinets to the top and not allow it to
expand and contract naturally or you risk the stress causing the top to
crack. So you need to build a framework, like a web frame, into the top of
the cabinets, and possibly but not necessarily, between the cabinets, that
will support the top and allow you to connect the two in a way that won't
prevent the top from expansion and contraction. There's a variety of ways
to fasten the top... wooden buttons, metal fasteners, so on. The top
basically floats on the cabinets. I think if you keep these considerations
in mind you can figure this out for yourself..


"DJ Delorie" wrote in message
...

Still working on my new desk: http://www.delorie.com/wood/desk/

Today's question is about supporting the center section of the top.
The primary support will be along the seam, held together with draw
bolts (although there's an arch across the widest part to help reduce
sagging). I want something along the seam that will align the
sections vertically as well as support the center section. My
original idea was just biscuits, but now I'm thinking floating tenons
would be better. Comments? Ideas? Suggestions?