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Formulas For Metal Fabrication

Below are some common formulas and requirements for calculating various material needs for metal fabrication of:

Rolled Cylinders or Rings

Custom Angles

Custom Channels

Metal Cones

Rolled Cylinders

There are two formulas for determining the flat layout for material requirements of rolled cylinders.  The determining factor is whether you are using inside diameter measurements or outside diameter measurements.  This will provide examples of both.

EXAMPLE 1:  OUTSIDE DIAMETER

1/2" thick Carbon Steel X 24" OD (23" ID) X 96" Length

Formula: (Outsidie Diameter X pi)-3 Times Material Thickness

24 X 3.1416=75.40

75.40 Inches - 1.5 Inches = 73.9 Inches

Therefore your flat layout for material required to make a 24" OD X 96" Length cylinder would be a flat plate 73.9" X 96"

EXAMPLE 2:  INSIDE DIAMETER

If we use the same cylinder but using the inside diameter we get the following:

1/2" thick Carbon Steel X 23" ID (24" OD) X 96" Length

Formula:  (Inside Diameter X pi)+3 Times Material Thickness

23 X 3.1416=72.26

72.26 Inches + 1.5 Inches = 73.8 Inches

Therefore your flat layout for material required to make a 23" ID X 96" Length cylinder would be a flat plate 73.8" X 96"

As you can see we come up with two dimensions that are very close whether we use inside diameter or outside diameter dimensions. 

To convert from inside to outside diameter add 2 times the thickness of material.

To convert from outside to inside diameter subtract 2 times the thickness of material.

Custom Angles

Angles are almost always specified by their outside dimensions.  For example if you measure the outside dimension a 1" X 1" Angle, then it will measure 1" X 1".  Inside dimensions are determined by the thickness of the material.  For example, if the 1" X 1" angle is 1/4" thick, then the inside dimension would be 3/4" X 3/4".  If it were 1/8" thick material, then the inside dimension would be 7/8" X 7/8".  With this being said, we can figure our inside dimension of an angle leg by taking the outside dimension and subtracting the thickness of the metal.  This is important when determining the size of material needed to make custom angles. 

EXAMPLE: Flat Layout for Custom Formed Angles

L6" X 6" X 1/4" thick X 96" Length Carbon Steel Angle

Outside Dimension of Angle - Material Thickness = Inside Dimension

6" - 1/4" = 5 3/4". In this example, both legs are the same length.  So we add these two dimensions together to get our flat layout of material.

5 3/4" + 5 3/4" = 11 1/2"

Therefore, we would require a piece of material 1/4" thick X 11 1/2" W X 96" L to form a L6" X 6" X 1/4" X 96" L Angle.

When custom fabricating angles, it must be noted that minimum material required to form an angle is 8 times the thickness of material plus 1/8".  For example, to form 1/4" material, 2 1/8" minimum width is required.  This allows the material to reach the back of the brake die for forming.

All information is based on the assumption that angles are 90 degrees. 

 Custom Channels

The same principles apply to channels that apply to angles with one exception:  subtract 2 times the thickness of the material for the web of the channel. 

EXAMPLE:  Flat Layout for Custom Fabricated Channel

1/4" Thick Carbon Steel Channel X 3" OD Leg X 6" OD Web X 3" OD Leg X 48" L

Inside Dimensions are determined by the following:

3"-1/4" (material thickness) = 2 3/4" Inside Dimension X 2 legs = 5 1/2"

6"-1/2"(2Xmaterial thickness)= 5 1/2" Inside Dimension web

5 1/2" + 5 1/2" = 11" Flat Layout

Flat Layout would then be 11" X 48" to form a channel 1/4" thick X 3" OD Leg X 6" OD Web X 3" OD Leg X 48" L.

These principles also apply to metal fabrications that have multiple breaks.

All information is based on the assumption that angles are 90 degrees. 

Metal Cones

When determining material requirements for metal cones, Eldred uses the latest software to calculate and program material requirements.  However, certain elements are required to determine the flat layout of the material needed.  The following illustration demonstrates the minimum factors needed for calculating cone material layouts.

Small Diameter: Either Inside or Outside Dimensions

Large Diameter:  Either Inside or Outside Dimensions

 

These are the minimum factors needed to determine material layout for metal cones. 

 

 

 

 

 

 

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