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Understanding Aluminum Extrusion Tolerances Video Series

This video series is an illustrative guide to the publication Understanding Aluminum Extrusion Tolerances and an explanation for the extrusion tolerance tables found in American National Standards Institute Standard H35.2 Standards Dimensional Tolerances for Mill Products and Aluminum Standards and Data.

These videos focus on common tolerances that need to be measured and explain proper procedures to calculate and measure them correctly.

Twist

Twist describes the rotation of an extrusion around an axis running through its length. Like if you were twisting two ends of a piece of pasta.

Tables to Reference in ASD:
10.14, 11.7, 12.7, 12.26 and 12.46

Straightness

Straightness tolerances limit the amount of curvature or bow in the extrusion. A simple way to visualize a deviation in straightness is to picture elbow macaroni. 

Tables to Reference in ASD:
10.15, 10.16, 11.6, 12.8, 12.25, 12.38, 12.45, 12.53

Flatness

Flatness is the absence of curvature in a surface when measured side to side. Flatness tolerances apply across the width of the extrusion only. Different flatness tolerances apply to solid profiles versus hollow profiles.

Tables to Reference in ASD:
11.8, 11.9, 12.9

Metal and Space Dimensions for Solid Profiles

Metal dimensions are just as the name implies, a dimension that applies to solid metal dimensions, such as a rod or bar’s thickness or where 75% percent or more of the dimension is metal.  Space dimensions apply to dimensions where more than 25% of the dimension is space such as the opening at the end of the legs on a channel.

Table to Reference in ASD:
11.2

Metal and Space Dimensions for Extruded Tube and Hollow Profiles

Metal dimensions are just as the name implies, a dimension that applies to solid metal dimensions, such as a rod or bar’s thickness or where 75% percent or more of the dimension is metal.  Space dimensions apply to dimensions where more than 25% of the dimension is space such as the opening at the end of the legs on a channel. 

Tables to Reference in ASD:
11.2, 12. 2, 12.3, 12.4

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