What you basically have to do is construct an ovally shaped wooden frame (perhaps upholstered) that fits to an equally shaped tabletop. You will see, my description allows lots of alterations (length and width of the table etc.) Therefore, all measures are just guidelines. You just have to make sure the parts fit together.
I used an existing tablebase (wooden frame, 4 legs), removed the old paint, painted it black and fixed the tabletop to it. The tablebase has a medium-size drawer, perfectly shaped to house a chiprack with 500 pokerchips, cards, dealerbutton etc. My table has enough space for 7 people.
Here’s what you need for the tabletop:

Material

1. plywood, thickness 26 mm, length 185 cm, width 115 cm (alter length if you want to sit more people)
2. plywood, thickness 10 mm, length 185 cm, width 115 cm (alter length according to 1.)
3. approx. 25 wooden dowels (depending on table dimensions)
4. white glue (for wood)
5. rubber foam, 5mm thickness, same dimensions as plywood
6. adhesive tape, coated both sides
7. artificial leather (if you want to upholster the frame), according to frame dimensions
8. rubber foam, approx. 20 mm thickness, lenght and width according to frame dimensions (if you want to upholster the frame)
9. tablecloth (wool, billiard cloth etc.)

Tools

1. electrical miter saw (good quality, make sure it‘s got a brand new blade suitable for plywood)
2. minimum 4 clamps
3. electrical drilling machine
4. stapler („heavy duty“), suitable for wood
5. grinding tools (file, paper)
6. ear protection (cutting is awfully noisy)
7. selfmade wooden „compasses“ according to table dimensions (see description and drawing)

Construction:

1. Put both plywoods on top of each other. Fix them together with clamps on all four corners
2. Drill holes through both plywoods, exactly where the centre of curvature of the round part of the table must be, see drawing
3. Construct wooden compasses according to drawing 2. „compasses“. Must have 4 holes: Center, R1 = outer radius of table, R2 = inner radius of bottom plywood, R3 = inner radius of top plywood Radii should be chosen according to the frame dimensions you require
4. Draw two half circles R1. R1 equals half the width of the plywood (in my case R1 = 57.5cm).The outer shape of your table is now visible
5. Draw two half circles R3 on top plywood, connect both circles with pen. Now you will see the inner dimensions of the frame
6. Drill holes (diameter depending on dowel size, dowels should fit firmly, even without glue) near the outer lines of the table. Distance between holes approx. 20 cm
7. Put the wooden dowels in the holes, Do NOT glue yet. Now the upper and lower plywood are fixed together (although removable) and you can take away the clamps
8. Take the miter saw and cut the outer curved lines of both plywoods. Cut slowly, yet IN ONE CUT. It will take some time to cut 35 mm of plywood. You may have to exchange blades, they easily wear when cutting plywood (in that case ONE CUT is impossible). Maybe you wish to protect your ears (my recommendation: YOU SHOULD)
9. Remove the dowels. You can now separate both layers of plywood again
10. Draw the inner radius (R2) on the bottom plywood, connect both half circles with lines
11. Cut the inner line (R3) of the top plywood alone
12. Cut the inner line of the bottom plywood alone

You should now have four elements: inner piece top plywood, outer ring top plywood, inner piece bottom plywood, outer ring bottom plywood
13. Put together both „outer rings“ by putting in dowels again. This time carefully glue dowels and wooden rings. Clamp the parts firmly together and allow glue to dry. Carefully cut outstanding pieces of dowels

You will now have three parts: Inner piece bottom plywood „the pokertable top“, inner piece top plywood „the dinnertable top“, and the combined part, the „frame“
14. Remove any dust from inner piece bottom plywood. Apply parallel stripes of double-coated adhesive tape. Remove release paper. Take rubberfoam (5 mm), carefully press it to adhesive. Trim foam edges around wood
15. Now you need perhaps a friend‘s help: Cover foam-covered tabletop with chosen cloth. Begin to staple it on one side, your helpful friend should thoroughly stretch the cloth. Make sure there are no wrinkles. Staple enough, distance appr. 1 inch
16. Trim excessive cloth
17. Now your cloth-covered tabletop is almost ready. Check wether the frame fits on top of it. Perhaps some inside grinding is necessary. The top plywood piece should fit into frame (now your dinnertable looks ready)
18. Fix whole assembly to substructure
The rest is cosmetics depending on your taste. You might want to thoroughly grind, polish and paint or veneer the wooden surfaces. Depending on foam thickness on tabletop, your frame may need a second layer of wood to cover the endgrain of the table entirely. If you wish to upholster the frame, use thicker and stiffer rubberfoam and cover it with artificial leather. You may even incorporate drinkholders (available e.g. at Gamblers‘ General Store, Las Vegas) into the frame
Enjoy your joiners work. It took me about eight hours to complete my table. Always good hands!
Rainer
PS: I would appreciate some feedback. This was my first technical description in english since years. Was it difficult or easy to understand? Was it too detailed or did you miss things?