Make sure that both the top and bottom panel scarfs are tight and that the top panels line up with the ones below them. To help maintain the alignment while the planks are being nailed, clamp the two planks together at both ends.
When you are satisfied that the planks are lined up correctly, put a piece of waxed paper on top of the scarf joint in the top plank. Using 2" x 2" scrap plywood pads to spread out the clamping pressure, drive 1"
nails through these plywood pads, through the middle of this top panel scarf, through the bottom panel, and into
your table top to clamp the scarfs tightly.