How to build a sturdy picnic table
Step 9: Place the outside boards
Lay the very outside table boards and outside seat boards in place.
That is four boards altogether; the two very outside table boards and the outside board on each seat.
Using the plans as reference, ensure that the boards are placed correctly and with the right amount of overhang each end.
Step 10: Fix the outside boards
When positioned correctly, clamp and fix the four outside boards by drilling and nailing with ONE NAIL ONLY at each meeting. This enables the whole unit to be slightly twisted if need be. Using a big set-square, check that the unit is square (that the seat and table boards are at right angles to the end frames), make any necessary adjustments and then drill and add a second nail at each meeting.
Step 11: Fix the intermediate boards
Lay the intermediate boards in place evenly spaced. They can be temporary held in place with wedges (see photograph).
When positioned correctly, fix by drilling and nailing with two 90mm (3 1/2") flat-head galvanized nails at each meeting.
TIP: Do not nail in a straight line. Zigzag the nails a little, this will help prevent possible splitting along the support members, especially with straight grain wood.