We wanted a round table that would seat a full Monopoly game. To do this we needed about a 5' diameter tabletop. The base was made consistent with the plans.
A few tips on the base:
- Get your angles as close to 45° as you can. Otherwise, there will be much sanding and puttying in your future.
- If you want to hide your lag screw like I did, I used a spade bit to recess an area for the screw head. Then I glued in a plug made from dowel and sanded flush.
If you want to make a round tabletop, here is what I did (there may be better methods). Keep in mind this was for a ~60" diameter table, I was assuming that the perimeter arc pieces would be about 4.5" wide and that I would cut the inner circle at a 50" diameter.
- Picture 1 - I built two 5' slabs of (7) 2x4s pocket-holed together.
- Picture 2 - Then I cut two pieces from each slab that would later make up the 90° "pie slice" pieces. Make sure to remove the screws that will be in the way your saw blade. Also, you just have to concern yourself with the angle since the radius will be dealt with later. There is a lot of wood waste with this method, but I think it avoided headaches.
- Picture 3 - I assembled (screwed and glued) the "pie pieces"to the cross pieces. The length of the cross pieces don't matter much since they will also be to cut to a specified radius. Since I would be cutting a 50" diameter circle, the large cross piece had to be at least 50" and the two small pieces had to be at least 22.25" (subtracting the 2x6 width).
- Picture 3 - I mounted my router to a piece of MDF and drilled a hole at the necessary distance to cut a 50" diameter circle. This distance is 25" + half of the bit diameter. Since I used a 1/2" straight bit, my point was 25.25" from the center of the router bit. I screwed this jig to the center of the tabletop assembly so the router could pivot and cut a circle. As for logistics, I rested this assembly on some scrap wood and kneeled on the tabletop as I was cutting it. It took a large number of passes with the router since I was cutting through 1.5" of material.
- Picture 4 - The perimeter pieces required some time and geometry. I found that I would need (8) 23" 2x8 pieces (the 23" is approximate because I was a little off for some reason, though I can't recall why). From those pieces, I used the same router jig to cut the perimeter arc pieces. You will need to make two new radius holes in teh jig to accomplish what you need. To cut the inner arc you need a hole set at 25" - half of the bit diameter (24.75" for me). To cut the outer arc, I used a hole that was 29 5/8" from the center of the router bit. You may need to do some fine tuning to these pieces to get them to fit correctly, but for me it pretty minor. I trimmed a couple pieces with a miter saw but that was it.
- The rest is screws and glue.