Dimensional tolerances only: diameter, ovality, wall thickness, length and straightness for nickel, nickel alloy and cobalt alloy aircraft tubing ordered to inch-pound dimensions. It contains no chemistry, no mechanical properties and no heat treatment requirements. Those come from the alloy’s own AMS specification, which AMS2263 is referenced alongside.
SAE AMS 2263F Standard
Aerospace tubing lives or dies on dimensions. SAE AMS2263F, Tolerances for Nickel, Nickel Alloy, and Cobalt Alloy Aircraft Tubing, is the specification that sets how far a nickel alloy aircraft tube may deviate on diameter, wall thickness, ovality, length and straightness before it is rejected.
It carries no chemistry and no mechanical properties. Those come from the alloy’s own AMS sheet. AMS2263 does one job: it defines the inch-pound manufacturing tolerances that apply to thin-wall aircraft tubing in nickel, nickel alloys and cobalt alloys.
Revision F was published in December 2022, superseding AMS2263E. This guide covers the scope, how mean diameter and ovality are defined, the tolerance tables for seamless, brazed and welded tubing, wall thickness rules and their alloy-specific exceptions, length and straightness limits, how AMS2263 differs from ASTM tolerance standards, and FAQs.
SAE AMS 2263F Free Download
SAE AMS 2263F Free Download
What Is SAE AMS 2263F?
AMS2263F covers established inch-pound manufacturing tolerances applicable to seamless and welded thin-wall aircraft tubing of nickel, nickel alloys and cobalt alloys ordered to inch-pound dimensions. The tolerances apply to all conditions and are based on individual measurements unless otherwise noted.
The standard was first issued in November 1948, reaffirmed in December 2017 and revised in December 2022. Revision F is the result of a five-year review, and the change made was to the title, clarifying the document’s applicability. Terms used in AMS specifications are defined in SAE AS7766.
One drafting convention is worth noting before reading any table. The term “exclusive” applies only to the higher figure of a specified range. A range written “Over 0.400 to 0.625 inch, exclusive” includes 0.400 but stops short of 0.625.
Scope Limits Worth Knowing
Three boundaries define what AMS2263 does and does not control, and each one sends you to a different document.
- Inch-pound only: the tolerances apply to tubing ordered to inch-pound dimensions, not metric
- Aircraft tubing only: thin-wall aircraft tubing, not general industrial pipe or tube
- Dimensions only: chemistry, mechanical properties and heat treatment come from the alloy’s own AMS specification
How AMS 2263 Defines Mean Diameter and Ovality
Two definitions govern every diameter table in the standard, and misreading either one causes disputes at inspection.
Mean diameter is the average of two measurements taken at right angles to each other at the same section. It is a single section’s average, not an average along the tube length.
Ovality is the difference between the maximum and minimum diameters of any one section of a tube. It is a within-section figure, which is why it appears as its own column alongside the OD tolerances rather than being folded into them.
The tables split OD tolerance into two pairs of columns: one pair applying to OD directly, the other to mean OD. Which pair applies depends on wall thickness as a percentage of OD, and the dividing line throughout the standard is 3.0 % of OD.
Thin-wall tubing, with wall at or below 3.0 % of OD, is measured on mean OD with a separate ovality allowance. Heavier wall above 3.0 % is controlled on OD directly, with no separate ovality figure. For the largest sizes in Tables 1 and 2, the standard also lists a mean OD tolerance alongside the OD tolerance.
Diameter Tolerances for Seamless Cold Finished Tubing
The standard gives separate diameter tables for two alloy families in the seamless cold-finished condition. Nickel-copper alloy and nickel-chromium-iron alloy are treated differently because their cold-working behaviour differs.
Annealed Nickel-Copper Alloy (Table 1)
Diameter tolerances for annealed nickel-copper alloy seamless cold-finished tubing, by specified OD and wall thickness as a percentage of OD. All values in inches.
| Specified OD, in. | Wall % of OD | OD Plus | OD Minus | Mean OD Plus | Mean OD Minus | Ovality |
| Up to 0.400, incl | Up to 3.0, incl | N/A | N/A | 0.004 | 0 | 0.004 |
| Up to 0.400, incl | Over 3.0 | 0.004 | 0 | N/A | N/A | N/A |
| Over 0.400 to 0.625, excl | Up to 3.0, incl | N/A | N/A | 0.005 | 0 | 0.005 |
| Over 0.400 to 0.625, excl | Over 3.0 | 0.005 | 0 | N/A | N/A | N/A |
| 0.625 to 1.500, incl | Up to 3.0, incl | N/A | N/A | 0.005 | 0.005 | 0.01 × OD |
| 0.625 to 1.500, incl | Over 3.0 | 0.005 | 0.005 | N/A | N/A | N/A |
| Over 1.500 to 4.500, incl | Up to 3.0, incl | N/A | N/A | 0.010 | 0.010 | 0.01 × OD |
| Over 1.500 to 4.500, incl | Over 3.0 | 0.010 | 0.010 | N/A | N/A | N/A |
| Over 4.500 to 6.000, incl | Up to 3.0, incl | N/A | N/A | 0.015 | 0.015 | 0.01 × OD |
| Over 4.500 to 6.000, incl | Over 3.0 | 0.030 | 0.030 | 0.015 | 0.015 | N/A |
| Over 6.000 to 7.500, incl | Up to 3.0, incl | N/A | N/A | 0.020 | 0.020 | 0.01 × OD |
| Over 6.000 to 7.500, incl | Over 3.0 | 0.040 | 0.040 | 0.020 | 0.020 | N/A |
| Over 7.500 to 8.625, incl | Up to 3.0, incl | N/A | N/A | 0.025 | 0.025 | 0.01 × OD |
| Over 7.500 to 8.625, incl | Over 3.0 | 0.050 | 0.050 | 0.025 | 0.025 | N/A |
Two patterns run through the table. Below 0.625 in. OD the minus tolerance on mean OD is zero, so small-bore tubing may run oversize but never undersize. From 0.625 in. upward the tolerance becomes symmetrical and ovality switches from a fixed figure to the proportional 0.01 × OD.
Monel 400 seamless tube is a typical nickel-copper alloy tube that falls under this table. The table is titled for annealed nickel-copper alloy, while the standard’s scope states that the tolerances apply to all conditions.
Annealed Nickel-Chromium-Iron Alloy (Table 2)
Diameter tolerances for annealed nickel-chromium-iron alloy seamless cold-finished tubing. The size bands differ from Table 1, and so do several of the values.
| Specified OD, in. | Wall % of OD | OD Plus | OD Minus | Mean OD Plus | Mean OD Minus | Ovality |
| Up to 0.400, incl | Up to 3.0, incl | N/A | N/A | 0.004 | 0 | 0.004 |
| Up to 0.400, incl | Over 3.0 | 0.004 | 0 | N/A | N/A | N/A |
| Over 0.400 to 0.625, excl | Up to 3.0, incl | N/A | N/A | 0.005 | 0.005 | 0.005 |
| Over 0.400 to 0.625, excl | Over 3.0 | 0.005 | 0.005 | N/A | N/A | N/A |
| 0.625 to 1.500, incl | Up to 3.0, incl | N/A | N/A | 0.0075 | 0.0075 | 0.01 × OD |
| 0.625 to 1.500, incl | Over 3.0 | 0.0075 | 0.0075 | N/A | N/A | N/A |
| Over 1.500 to 3.500, incl | Up to 3.0, incl | N/A | N/A | 0.010 | 0.010 | 0.01 × OD |
| Over 1.500 to 3.500, incl | Over 3.0 | 0.010 | 0.010 | N/A | N/A | N/A |
| Over 3.500 to 4.500, incl | Up to 3.0, incl | N/A | N/A | 0.015 | 0.015 | 0.01 × OD |
| Over 3.500 to 4.500, incl | Over 3.0 | 0.015 | 0.015 | N/A | N/A | N/A |
| Over 4.500 to 6.000, incl | Up to 3.0, incl | N/A | N/A | 0.020 | 0.020 | 0.01 × OD |
| Over 4.500 to 6.000, incl | Over 3.0 | 0.040 | 0.040 | 0.020 | 0.020 | N/A |
| Over 6.000 to 6.625, incl | Up to 3.0, incl | N/A | N/A | 0.025 | 0.025 | 0.01 × OD |
| Over 6.000 to 6.625, incl | Over 3.0 | 0.050 | 0.050 | 0.025 | 0.025 | N/A |
The nickel-chromium-iron table is looser than the nickel-copper table in the 0.400 to 1.500 in. range and coarser at the top. At 0.625 to 1.500 in. it allows 0.0075 in. against the nickel-copper table’s 0.005 in., and it breaks 1.500 to 4.500 in. into two bands rather than one, holding 0.010 in. only up to 3.500 in.
Inconel 600 seamless tube is the classic nickel-chromium-iron alloy governed here, with 72 % minimum nickel, 14–17 % chromium and 6–10 % iron putting it squarely inside the family this table names.
AMS2263F names alloy families rather than trade names, so for alloys such as Incoloy 800 the purchaser should confirm with the governing alloy AMS specification whether the nickel-chromium-iron tolerances in Table 2 apply.
Diameter Tolerances for Copper Furnace Brazed Tubing
Copper furnace brazed cold-finished nickel-copper alloy tubing gets its own short table, covering eight discrete size and wall combinations rather than size ranges. All values in inches.
| Specified OD | Specified Wall | OD Plus | OD Minus |
| 0.125 | 0.028 | 0.001 | 0.001 |
| 0.188 | 0.028 | 0.001 | 0.001 |
| 0.250 | 0.028 | 0.003 | 0 |
| 0.312 | 0.028 | 0.003 | 0 |
| 0.375 | 0.028 | 0.003 | 0 |
| 0.500 | 0.028 | 0.005 | 0 |
| 0.625 | 0.028 | 0.005 | 0 |
| 0.625 | 0.035 | 0.005 | 0 |
Note the break at 0.250 in. The two smallest sizes carry a symmetrical 0.001 in. tolerance; from 0.250 in. upward the minus tolerance drops to zero. Brazed tubing above 0.250 in. OD may run oversize but never undersize.
Diameter Tolerances for Welded Tubing, All Alloys
Welded tubing is handled in one table covering all alloys, and it introduces an ID column the seamless tables do not have. Values in inches, plus and minus.
| Specified OD, in. | Wall % of OD | OD ± | ID ± | Ovality |
| Up to 0.094, incl | Up to 3.0, incl | 0.001 | 0.001 | 0.001 |
| Up to 0.094, incl | Over 3.0 | 0.001 | 0.001 | N/A |
| Over 0.094 to 0.1875, excl | Up to 3.0, incl | 0.0015 | 0.0015 | 0.002 |
| Over 0.094 to 0.1875, excl | Over 3.0 | 0.0015 | 0.0015 | N/A |
| 0.1875 to 0.500, excl | Up to 3.0, incl | 0.003 | 0.005 | 0.004 |
| 0.1875 to 0.500, excl | Over 3.0 | 0.003 | 0.005 | N/A |
| 0.500 to 1.000, excl | Up to 3.0, incl | 0.004 | 0.006 | 0.01 × OD |
| 1.000 to 1.500, excl | Up to 3.0, incl | 0.005 | 0.007 | 0.01 × OD |
| 1.500 to 2.000, excl | Up to 3.0, incl | 0.006 | 0.008 | 0.01 × OD |
| 2.000 to 2.500, excl | Up to 3.0, incl | 0.007 | 0.010 | 0.01 × OD |
| 2.500 to 3.500, excl | Up to 3.0, incl | 0.010 | 0.014 | 0.01 × OD |
| 3.500 to 5.000, excl | Up to 3.0, incl | 0.015 | 0.020 | 0.01 × OD |
Two rules sit above this table and both change how it is used. OD tolerances apply to mean OD for tubing with specified wall of 3 % or less of specified OD. And critically, OD and ID tolerances shall not both apply to the same lot of tubing.
That second rule is a purchasing decision, not a manufacturing detail. The buyer picks which dimension is controlled. Specify OD control for tubing that must fit into a fitting, and specify ID control where flow area or an inserted component governs, but you cannot have both held to the table simultaneously.
The ID tolerance is consistently looser than the OD tolerance across the range, widening from parity at the smallest sizes to 0.020 in. against 0.015 in. at the top. That gap is the wall thickness variation showing through.
Wall Thickness Tolerances and Their Alloy Exceptions
The baseline for seamless cold-finished tubing is ±10 %. Wall thickness of all tubes except those alloys and sizes specifically excepted shall not vary more than that. Three sets of exceptions then widen it.
| Condition | Wall Tolerance | Applies To |
| Seamless, cold finished (baseline) | ±10 % | All alloys and sizes except those below |
| Nickel-copper alloy, seamless | ±12.5 % | OD over 0.400 to 0.625 in. excl with wall 0.040 in. and over; wall more than 25 % of OD; tubes over 4.500 in. OD |
| Nickel-chromium-iron alloy, seamless | ±15 % | OD over 0.400 to 0.625 in. excl with wall 0.042 in. and over; wall more than 25 % of OD |
| Nickel-chromium-iron alloy, seamless | ±12.5 % | Tubes over 4.500 in. OD |
| Copper furnace brazed, cold finished | ±0.002 in. | Nickel-copper alloy tubes (an absolute figure, not a percentage) |
| Welded, OD 0.625 in. and under | Seamless tolerances apply | All alloys |
| Redrawn welded tubing | ±10 % | All alloys |
The copper furnace brazed row is the outlier. ±0.002 in. is an absolute tolerance, not a percentage, so on a 0.028 in. wall it works out at roughly ±7 %, which is tighter than any percentage-based row in the standard.
Thick-wall tubing is treated as a special case twice over. Where wall exceeds 25 % of OD, the nickel-copper family moves to ±12.5 %, and the nickel-chromium-iron family moves to ±15 %.
Welded Tubing Wall Thickness (Table 5)
Welded tubing above 0.625 in. OD follows its own table, with the tolerance set by specified wall thickness and varying across four OD bands. Values in inches, plus and minus.
| Specified Wall, in. | OD Over 0.625 to 1.000 excl | OD 1.00 to 2.00 excl | OD 2.00 to 4.00 excl | OD 4.00 to 5.00 excl |
| Up to 0.025, incl | 0.002 | 0.003 | N/A | N/A |
| Over 0.025 to 0.028, incl | 0.003 | 0.003 | N/A | N/A |
| Over 0.028 to 0.032, incl | 0.003 | 0.004 | 0.004 | N/A |
| Over 0.032 to 0.049, incl | 0.003 | 0.004 | 0.005 | 0.005 |
| Over 0.049 to 0.058, incl | 0.004 | 0.005 | 0.005 | 0.006 |
| Over 0.058 to 0.065, incl | 0.005 | 0.005 | 0.005 | 0.006 |
| Over 0.065 to 0.095, incl | 0.005 | 0.005 | 0.006 | 0.007 |
| Over 0.095 to 0.120, incl | 0.005 | 0.006 | 0.007 | 0.007 |
| Over 0.120 to 0.134, incl | N/A | N/A | 0.007 | 0.007 |
| Over 0.134 to 0.165, incl | N/A | N/A | 0.008 | 0.008 |
The blank cells matter as much as the numbers. Thin walls are not available in large diameters and heavy walls are not available in small ones. The N/A cells mark combinations the standard does not give a tolerance for.
Length and Straightness Requirements
Definite lengths shall not vary more than plus 0.125 inch, minus 0. The minus-zero rule means a cut length is never short, so a tube ordered at 36 inches arrives between 36.000 and 36.125 inches.
Straightness applies to tubing 4 inches and under in specified OD. Maximum curvature, measured as depth of arc, shall be not greater than 0.060 inch in any 3 feet of length, or 0.020 inch × length in feet for shorter lengths.
The two formulations meet at 3 feet and they are not interchangeable above it. The 0.060 in. figure is a per-3-foot limit applied to any 3-foot portion, which is a stricter control on a long tube than a single end-to-end measurement would be.
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How AMS 2263 Differs From ASTM Tolerance Standards
Buyers moving between aerospace and industrial supply meet different tolerance regimes for the same alloys. The table sets AMS2263 against the ASTM general requirements specifications that govern industrial nickel alloy tube.
| Parameter | SAE AMS2263F | ASTM B829 / B751 |
| Product scope | Thin-wall aircraft tubing | General nickel alloy pipe and tube |
| Units | Inch-pound only | Inch-pound with SI conversions |
| Alloy grouping | By family: Ni-Cu, Ni-Cr-Fe, cobalt | By UNS number and product condition |
| Thin-wall threshold | 3.0 % of OD | 3 % of OD |
| Ovality treatment | Separate column, fixed or 0.01 × OD | Folded into OD tolerance with stated exceptions |
| OD vs ID control | Welded tubing: buyer picks one, not both | OD controlled throughout |
| Length tolerance | +0.125 in. / −0 for definite lengths | +1/8 to +3/16 in. / −0 by size |
| Straightness | 0.060 in. per 3 ft for OD 4 in. and under | Reasonably straight, free of bends and kinks |
The headline difference is the wall tolerance philosophy. AMS2263 uses a symmetrical ±10 % band; ASTM B829 uses an asymmetric +22 % / 0 on nominal wall. An aerospace tube may run thin by up to 10 %; an industrial nominal-wall tube never runs thin at all.
That reflects different failure concerns. Aerospace tubing is weight-critical and dimensionally controlled for fit; industrial pressure tubing is pressure-critical and controlled so that wall never falls below design. Neither regime is tighter overall, since they are tight in different places.
For industrial nickel alloy supply, nickel alloy tube ordered to ASTM B163 with B829 general requirements is the normal route, and AMS2263 does not apply unless the purchase order calls for aircraft tubing to AMS dimensions.
What to State on an AMS 2263 Purchase Order
AMS2263 is a tolerance document referenced alongside an alloy specification, never on its own. A complete order needs both, plus several choices the standard leaves to the purchaser.
- Alloy AMS specification: the sheet carrying chemistry, mechanical properties and heat treatment
- AMS2263 reference: for the dimensional tolerances
- Manufacturing method: seamless cold finished, welded, redrawn welded, or copper furnace brazed; each has its own table
- Specified OD and wall thickness: in inches, since the standard is inch-pound only
- OD or ID control for welded tubing: the standard forbids both applying to one lot
- Definite or random lengths: the +0.125 in. / −0 tolerance applies to definite lengths
The wall-as-percentage-of-OD figure decides which columns of the diameter table apply, so it is worth calculating before the order goes out. A 1.000 in. OD tube with 0.030 in. wall sits at 3.0 % and falls on the mean OD side of the line; the same OD with 0.035 in. wall is 3.5 % and moves to direct OD control.
For an example of an alloy specification that calls up AMS2263 directly, see the SAE AMS 5589 standard page, which overrides it for one OD band and defers to it for every other size.
Summary
AMS2263F is a tolerance sheet, not a material specification. It fixes diameter, ovality, wall, length and straightness for nickel, nickel alloy and cobalt alloy aircraft tubing in inch-pound sizes, and it is always read alongside the alloy’s own AMS specification.
Three numbers carry most of the work. The 3.0 % of OD threshold decides whether mean OD or direct OD applies, ±10 % is the baseline wall tolerance before alloy exceptions, and definite lengths run plus 0.125 inch minus zero. Get those right on the order and the rest of the standard follows.
Frequently Asked Questions
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What Does AMS 2263 Actually Specify?
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What Is the Difference Between OD and Mean OD in AMS 2263?Mean diameter is the average of two measurements taken at right angles at the same section. OD tolerance applies to individual measurements. Which applies depends on wall thickness: at or below 3.0 % of OD the mean OD columns apply with a separate ovality allowance; above 3.0 %, the direct OD columns apply.
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What Is the Standard Wall Thickness Tolerance?±10 % for seamless cold-finished tubing, with exceptions widening it to ±12.5 % or ±15 % for certain alloys and sizes. Nickel-copper alloy moves to ±12.5 % in three defined cases; nickel-chromium-iron alloy moves to ±15 % in two cases and ±12.5 % above 4.500 in. OD. Copper furnace brazed nickel-copper tubing uses an absolute ±0.002 in.
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Can Both OD and ID Tolerances Apply to Welded Tubing?No. The standard states that OD and ID tolerances shall not both apply to the same lot of tubing. The purchaser chooses which dimension is controlled: OD where the tube must fit into a fitting, ID where flow area or an inserted component governs.
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How Straight Must AMS 2263 Tubing Be?For tubing 4 inches and under in specified OD, maximum curvature measured as depth of arc shall not exceed 0.060 inch in any 3 feet of length, or 0.020 inch × length in feet for shorter lengths. The per-3-foot basis means a long tube is checked in portions rather than end to end.
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What Changed in Revision F?AMS2263F is the result of a five-year review, and the revision updated the title to clarify the document’s applicability. It was published in December 2022 superseding AMS2263E. A change bar in the left margin of the standard marks areas where technical revisions were made.
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Does AMS 2263 Apply to Metric Tubing?No. The scope covers tubing ordered to inch-pound dimensions. Tubing ordered in metric sizes falls outside the scope of AMS2263F.
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Which Alloys Does AMS 2263 Cover?Nickel, nickel alloys and cobalt alloys. The diameter tables name two families specifically, nickel-copper alloy and nickel-chromium-iron alloy, in the seamless cold-finished condition. The welded tubing table covers all alloys in one set of values, and the copper furnace brazed table covers nickel-copper alloy only.
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How Does AMS 2263 Compare With ASTM B829?AMS2263 governs thin-wall aircraft tubing in inch-pound sizes with a symmetrical ±10 % wall tolerance. ASTM B829 governs general nickel alloy pipe and tube and sets wall tolerances in its own size-dependent tables, typically an asymmetric +22 % / 0 on nominal wall. The two standards control different things for different reasons, so check each against the purchase requirement.