To make precise pie cuts bends I have provided a nice simple formula. This formula makes a bend that is 90 degrees.
CLR = Center Line Radius (radius of the bend measured through the center of the tubing)
D = Diameter of Tube _____
L = Length of long side of pie cut - the top of this pie cut -> \____/
Angle = angle to cut pie section which, this angle is measured perpendicular to the length of the tubing
N = number of pie sections to complete bend
* means multiply
L = [ ( 2 * CLR ) + D ] * [ sin ( Angle ) ]
Angle = 45 / N
Example:
Madmax May 27, 2007
You want to make a bend that uses 3" diameter tubing with a CLR of 4" and 5 pie sections.
L = [ ( 2 * 4" ) + 3" ] * [ sin ( 45 / 5 ) ]
L = [ 8" + 3" ] * [ sin ( 45 / 5 ) ]
L = [ 11" ] * [ sin ( 45 / 5 ) ]
L = [ 11" ] * [ sin ( 9 ) ]
L = [ 11" ] * [ 0.156 ]
L = 1.716"
Angle = 9 degrees
_____
Now you need to cut 5 of these -> \____/ with the top part measuring 1.716" in length.