We were to build a 42″ round, pedestal, dining table in cherry. Cost was an issue so we bought the column and legs and only had to make the table’s top, assemble the parts and finish it. No skirt. Just a single center ‘stretcher’, sitting underneath at 90 degrees to the table top’s planks.
We purchased extra thick cherry (1&1/2″) in rough form (from the mill), machined the board’s faces to make them dead straight and true (flat w/ square edges). We positioned the boards to one another to achieve a 42″ round without any sapwood before gluing together.
We used double stacked biscuits (makes the top stronger) every 10 inches or so, glued all edges completely, pipe clamped and (with a wet rag) removed all the glue that had seeped from all the seams (which could prevent stain from taking during finishing).
One of the ways to minimize any curvature to the top is to alternate the growth rings from one board to the next. In this picture of the glue-up, I used photoshop to highlight the boards rings on the end grain.
I cut the circle by making a number of passes, each 1/4″ deeper than the last, until the cutting bit (blade) made it all the way through. The speed at which I moved the router was important as too fast could create ‘tear out’ at the table top’s edges and too slow would leave the exposed edge with burn marks (which can be hard to remove by sanding). I cleaned the bit often and used a blade coating spray on the cutting bit to minimize burn. Here you can see the clean arc being created after the first of five passes with the router.
To attach the table top to the pedestal, we made a stretcher board which sits just beneath the top. This will help keep the table’s top flat and still allow for it’s inevitable movement through the seasons (expansion and contraction). Here you see my illustration of it and the actual piece attached to the base.