barrel sauna

[Unregistered-rylwrx]

Does anyone know what degree I’d have to cut 2x8s to make an 8 ft diameter barrel?

[doug seibert]

Using trigonometry you can compute the angle using the Law of Cosines…….

Or “By Construction”…..
Take a piece of your 2×8 and using a square draw Two lines across the board exactly 48″ apart……..Then draw a straight line from the Mid-point of one line to the Outside-edge of the second line…….the angle between these two lines is the bevel you need to cut on each edge of your staves…….

[bink]

Check my arithmetic.

D = diameter.
C = Circumference.
pi = 3.14159 ……..

D = 8 ft
C = pi X 8 ft = 25.13274

Width of finished 2X8 = 7.25 in

Number of boards = (25.1324 X 12) / 7.25
= 41.6
~ 42 boards
Sum of interior angles (regular polygon) = (180(n-2) = 180(42-2) = 180(40) = 7200 degrees.

Interior angle = 7200/42 = 171.428….

Cut angle is 1/2 of that = 85.714 ~ 86 degrees.

I think, that is correct.

Let us know how it works out.

[Author]

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