Formula for making precise PIE CUT BENDS............!!!!
05-27-2007, 04:47 AM
#1
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Thread Starter
Join Date: May 2005
Posts: 0
Formula for making precise PIE CUT BENDS............!!!!
To make precise pie cuts bends I have provided a nice simple formula.
This formula makes a bend that is whatever angle you desire.
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
Bend Angle = The angle of the bend
N = number of pie sections to complete bend
* means multiply
L = [ ( 2 * CLR ) + D ] * [ sin ( Angle ) ]
Angle = Bend Angle / ( 2 * N )
Example:
You want to make a bend that is 120 degrees, uses 3" diameter tubing with a CLR of 4", and 5 pie sections.
Angle = Bend Angle / ( 2 * N )
Angle = 120 / ( 2 * 5 )
Angle = 12
L = [ ( 2 * CLR ) + D ] * [ sin ( Angle ) ]
L = [ ( 2 * 4" ) + 3" ] * [ sin ( 12 ) ]
L = [ 8" + 3" ] * [ sin ( 12 ) ]
L = [ 11" ] * [ sin ( 12 ) ]
L = [ 11" ] * [ sin ( 12 ) ]
L = [ 11" ] * [ 0.208 ]
L = 2.288"
[size=16pt]L = 2.288"
Angle = 12 degrees
_____
Now you need to cut 5 of these -> \____/ with the top part measuring 2.288" in length.
Here is an Excel ------sheet that t_cel_t created that uses this formula for you mathematically challenged individuals. Pie Cut Excel Sheet
EDIT*
Here's the downpipe and mani I did for my car. It's 3", uses 5 pieces per 90*, and has a CLR of 3"[/size]
This formula makes a bend that is whatever angle you desire.
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
Bend Angle = The angle of the bend
N = number of pie sections to complete bend
* means multiply
L = [ ( 2 * CLR ) + D ] * [ sin ( Angle ) ]
Angle = Bend Angle / ( 2 * N )
Example:
You want to make a bend that is 120 degrees, uses 3" diameter tubing with a CLR of 4", and 5 pie sections.
Angle = Bend Angle / ( 2 * N )
Angle = 120 / ( 2 * 5 )
Angle = 12
L = [ ( 2 * CLR ) + D ] * [ sin ( Angle ) ]
L = [ ( 2 * 4" ) + 3" ] * [ sin ( 12 ) ]
L = [ 8" + 3" ] * [ sin ( 12 ) ]
L = [ 11" ] * [ sin ( 12 ) ]
L = [ 11" ] * [ sin ( 12 ) ]
L = [ 11" ] * [ 0.208 ]
L = 2.288"
[size=16pt]L = 2.288"
Angle = 12 degrees
_____
Now you need to cut 5 of these -> \____/ with the top part measuring 2.288" in length.
Here is an Excel ------sheet that t_cel_t created that uses this formula for you mathematically challenged individuals. Pie Cut Excel Sheet
EDIT*
Here's the downpipe and mani I did for my car. It's 3", uses 5 pieces per 90*, and has a CLR of 3"[/size]
05-27-2007, 11:58 AM
#5
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Join Date: Aug 2003
Location: NE-PA
Posts: 4,666
Re: Formula for making precise PIE CUT BENDS............!!!!
Originally Posted by CSaddict
My formula is eyeball x pipe / radius of the imaginary pipe in my mind= close enough.
