HI,
I make tables from almost exclusively reclaimed timber and some of it can be pretty wet.
The thing to bear in mind is that timber expands when it gets wet and contracts when it dries in all directions but mainly 'across the field' i.e. across the grain. So, if you make a simple top by gluing together lengths of wood it will become narrower when it dries. Is this a problem? Depends... If you add end sections to the top whose grain runs at 90 degrees to the rest of the table you will end up with a 'step' when the main part of the top has dried. One solution I've found is to revisit the table a few months after completion and sand the ends flush. Of course, the table owner may like this effect as it reflects the rustic nature of the table.
A more important consideration is how to prevent the table splitting when it shrinks as the more resilient ends will, unless assembled in such a manner to prevent it, hang onto the main section causing splits. How you overcome this is to machine a tongue on the main section and a groove on the ends (I prefer to stop just short so the t&g are hidden) but only glue the central area of the tongue. The outer parts I secure with pegs passing through round holes in the ends and oval holes in the tongue so that the pegs 'slide' when the top shrinks.
To secure the top to the base I machine a groove around the inside of the base's rails to accept the tongues of some cleats that are screwed to the underside of the top. The screw holes through the cleats should be oversize to accommodate movement maybe even with washers under the screws.
Oh, a simpler solution is to not attach ends at all as it's only an aesthetic to hide the end grain but in making rustic furniture that isn't always important. For example... It took me three days recently to turn some wet and rotten wood extracted from a pile of firewood lying uncovered in a heap at the bottom of my garden into a coffee table for a local coffee shop. The top has warped and cupped dramatically but the shop owner and his customers love it! True a couple of ends would have gone some way to prevent the cupping but it would have lost so much character in the process and become just another coffee table instead of the dramatic conversation piece is become.
This probably took longer to type than it would to have actually made a table
If still unsure PM me and I'll send some drawings.
Cheers,
John
