# Geometry Flat Out Length Lecture by n09C7b

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```									     Geometry

Compute Flat-out Length
Flat-out Length
To end up with this part as dimensioned…
150 mm                 Stock Thickness = 2.5 mm

32 mm
145 mm

…how long must the original material be?
322 mm

Flat-out Length
Key Concept
Distinguish between Inside and Outside
dimensions.
inside

outside    inside

outside
Inside & Outside Dimensions
59 mm

Stock Thickness = 2 mm

68 mm
64 mm

85
83 mmmm
Procedure
Check the dimensions of the finished part.
– If there are any “outside” dimensions, convert
them to “inside” dimensions.

Flat-out Length = Sum of all the inside dimensions

Assumptions
1) The stock is relatively thin.
2) The bends are sharp & 90
Example
Determine the flat-out length.
120 mm
Stock Thickness =
3 mm

92 mm          42 mm

92mm + 39 mm + 117 mm = 248 mm
Circles
To compute the flat-out length of a circle
(or arc), reference off the centerline of the
material.
Example
Determine the flat-out length to needed to
make this circular object.
Thickness = 0.3”

O.D. = 8.5”

C=d
C = 3.14 x 8.2”
C = 25.748”
Example – Arcs
Compute the flat-out length needed to
make the arc (1/4 circle).
Thickness = 6 mm