Saw away and repeat for all four corners. Check again on both sides to make sure the level did not shift during clamping. Now you have a guide for a straight cut. Now go to the other side of the line and again place your saw at the line to be cut and adjust the other side of the level to lay against your saw. I then took the level and placed it against the edge of the saw as straight as possible to the other side of the line to be cut. First I placed my saw on the line I will be cutting. In order to make these cuts as straight as possible I used a level clamped down on the board as a guide for my saw. Place your board on a table or stand, I used some bar stools, and get your clamps, saw and straight edge or level. Take your straight edge and draw a line from one mark to another at each corner, see picture with note. At this point each edge should have two marks. Take this number and measure from one side of the board to the other on the edge and mark it, see picture with note. For a 50'x50' board the measurement is 35 3/8'. It doesn’t matter which corner since it is the same all around. Next measure the distance between the center of the board to one of the corners. This should create a 'X' on your board and where the 2 lines intersect in the middle is the center of your board. Start off by drawing a straight line from one corner to another corner. For the purpose of this how-to I will be using my measurements. The first thing we have to do is measure out our octagon. Since my car does not have a huge trunk I needed to cut it to fit it in. In my pictures you will see mine in two pieces. This will be smaller than the 52' poker table top and will create a nice looking lip in the end. For this you will need the 50'x50' MDF board.

Octagon folding poker table with legs