Replies

1. 
   JoeWood | May 14, 2004 09:34pm | #1

   This should help you.

   http://www.josephfusco.org/Calculators/Advanced_Box_Cutter.html

2. 
   Elcoholic | May 14, 2004 11:44pm | #2

   Look at half of each triangle making up the octagon as a right triangle where the angle opposite the side you want = 22.5* and the hypotenuse = 8'. 

   Solve (8)*Sine 22.5 = X

   (8) 0.382499 = 3.01

   2 * 3.01 = 6.11'

   If your 8' is measured from the surface of the tree then you

   ll have to add the radius of the tree to the 8', so if the tree is 36" dia then solve

   (2)(8+1.5)(0.382499) = 7.3'

   John O'Connell - JKO Handcrafted Woodworking

   Life is tough.  It's tougher if you're stupid - John Wayne

3. 
   robkelly | May 15, 2004 02:48am | #3

   Lay it out on the ground and measure with a tape measure. If you don't already have the wood for the radial supports, take the tape and some chalk to a parking lot. Church parking lots are empty most of the week so there's lots of space to work. Once you have chalked the figure on the pavement, resist the temptation to inscribe satanic signs around the edges, as this is a poor use of consecrated ground.

1. 
   UncleDunc | May 15, 2004 01:27pm | #4

   Besides, the demons you can summon with an octagon are pretty small beer.

1. 
   robkelly | May 16, 2004 03:38am | #8

   Not even that, if it's a Methodist parking lot.

4. 
   notDusty | May 15, 2004 04:47pm | #5

                        Dave ,

          Just for fun and some design ideas do a Google on "Out and About Tree Houses" located in S.W. Oregon . This guy is the guru on tree houses .

5. 
   datachanel | May 15, 2004 04:47pm | #6

   I've got a wonderful little book called The Backstage Handbook.  One of the tricks it has under geometric shapes is how to draw regular geometric shapes (all sides equal in length) using chords (a chord is a line segment that touches the circumference of the circle twice).  It includes a table of constants to help determine the length of the side of the polygon.  Simply multiply your radius by the constant for the number of sides you want and that will give you the length of your side. Note, this is for a polygon inscribes inside a circle. I'll include some common ones for any body else who is interested.

   No. of Side      Constant

   3......................1.732

   4......................1.414

   5......................1.175

   6......................1.000

   7......................0.8677

   8......................0.7653

   9......................0.6840

   10....................0.6180

   12....................0.5176

   36....................0.1743

   So if the radius you  want is 8 ft, multiply 8*0.7653=6.1224ft.

   Hope this helps and have fun with your tree house.

   Datachanel

   Doing things the hard way

1. 
   Dave11ut | May 15, 2004 08:54pm | #7

   Thanks for everyones input.

   As soon as I have it (treehouse) finished I will post some pics. 

   Everyone should do a project like this with their kids.  It has been a ton of fun so far and we haven't even started building yet!