Clamp curved caul edges inwards so they align tabletop boards in the middle, then torque up the main clamps to draw the boards together. If the width of boards you’re using allow it, pre-glue boards for your tabletop in sections that are just narrow enough to fit within your thickness planer. Run these through the planer to clean and level the glue joints, then move back to clamps for final glue up. Working in stages like this reduces the number of glue joints you need to sand smooth and level later.
Building a table is one of the most deceptively simple woodworking projects going. What could be easier than gluing up a few boards and applying a finish, right? But reality is often surprising, because building a top for that table can go wrong in ways you might not realize until it’s too late.  Here are my favourite tabletop construction tips, plus advice on how to avoid trouble.