I would like to make a table with an octagon top, about 48 inches, and I kind of forgot how to lay it out. I know it was covered in high school math but that was many brain cells ago. Any help?
Thanks,
Greg
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Replies
Square 48 inches on each side; Circle 48 inches diameter inscribed inside square; 45-degree angles tangent to circle. Is this what you need to know?
Cadiddlehopper
GW52,
Not sure about HS...but, they are all 45 degree angles from the center. (8 times 45 = 360) then just connect the lines at 24" from the center...I thnk?
GW52
I'm no geometric wiz-But I do have AutoCad!
Roughly 19.88 length for the sides. Oppposite sides being 48" apart.
Alan
Alan,
Thanks for the reply, I seem to recall some type of math formula where you take the diameter and multiply it by some number... to get the dimension of 1 side and this is where the brain cells died!
Thanks,
Greg
Edited 8/25/2006 2:42 pm ET by GW52
Greg -
Construct a 48 x 48 square
Find the center of the square by drawing diagonals.
Measure distance "d" from a corner of the square to the center. A large compass is best for this.
Put the point of the compass on a corner, and mark off the distance "d" on both adjacent sides. Do this with all four corners.
At each corner, draw a line through adjacent marks.
There's your octagon.
Ed
To add to what Ed gave as a method, if a calculator is handy (in case you don't have a large compass or trammel), take the measure of the side of your square (48" in this example), and divide it in half (eg., 48/2=24"). Then take this value (24") and multiply it by √2 (which is 1.4142...): 24" * √2 = 33.941", or 33-15/16". Finally, take this measure (which happens to be the same measure as the radius of the circle Ed mentioned in his method), and lay off this distance from each corner along each side of the square adjoining the corner. Each corner generates 2 marks, or 8 marks in total. On each side of the square, then, these marks will denote the corners of the octagon. Connect the marks and you're done.I hope that made sense. I can upload a diagram if that's of help to anyone.
Thanks,
Greg
Why all the mathematics??? Just put the lines on the panel. All that's needed is a piece of cardboard with holes 24 inches apart (or a trammel compass), a pin, a pencil, & a sliding square with a 45-degree angle on it. A yardstick may be handy since it is large. Find panel center, draw circle from center, draw lines tangent to circle 45 degrees from edges. That's it. No calculator needed.Cadiddlehopper
Tucked this site it my calculators folder in my bookmarks because sooner or later I would need it. Looks like youll benifit from it before I do.
http://www.members.cox.net/ultimate_poker_table_top/Octagon%20Layout%20Calculator.html
An easy way to do it is to make a 48"square. Then make diagonal lines from corner to corner. Then use a scrap piece of wood that is the length of one corner to centre. Then go from one corner to adjacent corner. Go all the way around then just connect all the marks and start cutting.
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