:::RHMT::: Real Home Made Turbo

General Category => Fabrication => Topic started by: 5thgenlx on March 09, 2009, 01:17:00 AM

Title: Precise Pie Cut Bend Formula
Post by: 5thgenlx on March 09, 2009, 01:17:00 AM
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.