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Seamless Tubing Tolerances and Specifications


Permissible Variations in Outside Diameter, Wall Thickness, and Cut-Length Variations
(Hot-Finished Round Tubing)
Specified Size, Outside Diameter, In. Ratio of Wall Thickness to Outside Diameter Outside Diameter, In. 0.109 In and Under 0.109 to 0.172 In. Incl. Over 0.172 to 0.203 In. Incl. Over 0.203 In. Permissible Variations In Cut Length In.
    Over Under Over Under Over Under Over Under Over Under Over Under
Under 3 All Wall Thicknesses 0.023 0.023 16.5 16.5 15 15 14 14 12.5 12.5 3/16 0
3 to 5 1/2 Excl. All Wall Thicknesses 0.031 0.031 16.5 16.5 15 15 14 14 12.5 12.5 3/16 0
5 1/2 to 8 All Wall Thicknesses 0.047 0.047         14 14 12.5 12.5 3/16 0
8 to 10 3/4 Excl. 5% and Over 0.047 0.047             12.5 12.5 3/16 0
10 3/4 to
12 3/4 Excl.		 Under 5% 0.063 0.063             12.5 12.5 3/16 0
These tolerances apply to cut lengths up to an including 24 Ft. (7.3M). For lengths over 24Ft. an additional over tolerance of 1/8in (3.1mm) for each 10ft. (3m) or fraction thereof shall be permissible up to a maximum tolerance of 1/2 in. (12.7mm)

Permissible Variations in Outside Diameter, Ovality, Wall thickness, and Cut-Length Variations (Cold Finished Round Tubing)
Outside Diameter, In. Outside Diameter Tolerance, In. Over and Under Ovality Double Outside Diameter Tolerance when wall is: Wall Thickness in % Permissible Variations in Cut Length, in.
Over Under Over Under
Under 1/2 0.005 Less than 0.015 In. 15 15 1/8 0
1/2 to 1-1/2 Excl. 0.005 Less than 0.065 In. 10 10 1/8 0
1 1/2 to 3 1/2, Excl 0.010 Less Than 0.095 In. 10 10 3/16 0
3 1/2 to 5 1/2 Excl 0.015 Less than 0.150 In. 10 10 3/16 0
5 1/2 to 8 Excl. 0.030 Less than 0.240 In. 10 10 3/16 0
8 to 8 5/8 Excl 0.045 Less than 0.300 In. 10 10 3/16 0
8 5/8 to
12 3/4		 0.062 Less than 0.350 In. 10 10 3/16 0
  1. Tolerances of tubes produced by the rod or bar mandrel process and which have an inside diameter under 1/2 in (12.7mm) (or an inside diameter under 5/8 in.  When the wall thickness is more then 20% of the outside diameter.) Are as shown in this table except that wall thickness tolerances are 10% over and under the specified wall thickness.
  2. For Ovality values, the tolerance for average outside diameter at any one cross section does not exceed the outside diameter tolerance value for the applicable outside diameter.
  3. Many tubes with wall thicknesses more then 25% of outside diameter or with wall thicknesses over 1 1/4 in.  Or weighing more then 90lb/ft. are difficult to draw over a mandrel.  Therefore the wall thickness can vary 12 1/2% over and under that specified.
  4. For those tubes with inside diameter under 1/2 in (or under 5/8 in when the wall thickness is more then 20% of the outside diameter) which are not commonly drawn over a mandrel, A is not applicable. Therefore the wall thickness can vary 15% over and under that specified, and the inside diameter is governed by both the outside diameter and wall thickness tolerances.
  5. These tolerances apply to cut lengths up to an including 24 ft.  For lengths over 24ft, an additional over tolerance of 1/8 in. for each 10ft. or fraction thereof shall be permissible, up to a maximum tolerance of 1/2 in.
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