Size chart
Anchor Shackle Size Chart: RR-C-271H Type IVA Dimensions
Source: RR-C-271H w/ Amendment 1 (2022-01-03). Dimensions from Table IX (page 20); working load limit from Table VIII. Classes 2 and 3, Grade A.
Type IVA as the specification defines it, with each dimension column it publishes. Each column keeps the meaning the specification gives it, so D, P, E, W, L, B, R are not interchangeable.
At a glance
For nominal size 1/2 in: minimum body dimension D 0.48 in, minimum pin diameter P 0.61 in, inside length L 1.88 in, and a Grade A working load limit of 4,000 lbf (2 short ton).
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Dimension table, Type IVA
One row per nominal size, in the order the specification lists them. Inch values are the specification's; millimetre columns are conversions at 1 in = 25.4 mm and are marked as such. W and L show the nominal tolerance the specification states for them; D, P, E, B and R are minimum or reference values without a tolerance band. The working load limit column is the specification's Grade A value for that nominal size and is the same figure on the anchor and chain pages, because one mechanical-property table covers both.
| Nominal size (in) | D min (in) | P min (in) | E ref (in) | W ±tol (in) | L ±tol (in) | B min (in) | R max (in) | D min (mm) | P min (mm) | E ref (mm) | W ±tol (mm) | L ±tol (mm) | B min (mm) | R max (mm) | WLL Grade A (lbf) | WLL Grade A (short ton) |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 3/16 | 0.18 | 0.24 | 0.31 | 0.38 ±0.13 | 0.88 ±0.06 | 0.56 | 0.63 | 4.6 | 6.1 | 7.9 | 9.7 | 22.4 | 14.2 | 16.0 | 650 | 0.325 |
| 1/4 | 0.24 | 0.3 | 0.4 | 0.47 ±0.13 | 1.13 ±0.06 | 0.75 | 0.88 | 6.1 | 7.6 | 10.2 | 11.9 | 28.7 | 19.0 | 22.4 | 1,000 | 0.5 |
| 5/16 | 0.3 | 0.37 | 0.47 | 0.53 ±0.13 | 1.25 ±0.06 | 0.81 | 1 | 7.6 | 9.4 | 11.9 | 13.5 | 31.8 | 20.6 | 25.4 | 1,500 | 0.75 |
| 3/8 | 0.36 | 0.43 | 0.53 | 0.66 ±0.13 | 1.44 ±0.13 | 0.93 | 1.13 | 9.1 | 10.9 | 13.5 | 16.8 | 36.6 | 23.6 | 28.7 | 2,000 | 1 |
| 7/16 | 0.42 | 0.49 | 0.59 | 0.75 ±0.13 | 1.69 ±0.13 | 1.06 | 1.25 | 10.7 | 12.4 | 15.0 | 19.0 | 42.9 | 26.9 | 31.8 | 3,000 | 1.5 |
| 1/2 | 0.48 | 0.61 | 0.72 | 0.81 ±0.13 | 1.88 ±0.13 | 1.18 | 1.38 | 12.2 | 15.5 | 18.3 | 20.6 | 47.8 | 30.0 | 35.1 | 4,000 | 2 |
| 5/8 | 0.59 | 0.73 | 0.84 | 1.06 ±0.13 | 2.38 ±0.13 | 1.5 | 1.88 | 15.0 | 18.5 | 21.3 | 26.9 | 60.5 | 38.1 | 47.8 | 6,500 | 3.25 |
| 3/4 | 0.71 | 0.85 | 0.97 | 1.25 ±0.13 | 2.81 ±0.25 | 1.75 | 2.13 | 18.0 | 21.6 | 24.6 | 31.8 | 71.4 | 44.4 | 54.1 | 9,500 | 4.75 |
| 7/8 | 0.83 | 0.98 | 1.09 | 1.44 ±0.13 | 3.31 ±0.25 | 2 | 2.38 | 21.1 | 24.9 | 27.7 | 36.6 | 84.1 | 50.8 | 60.5 | 13,000 | 6.5 |
| 1 | 0.95 | 1.1 | 1.22 | 1.69 ±0.13 | 3.75 ±0.25 | 2.31 | 2.63 | 24.1 | 27.9 | 31.0 | 42.9 | 95.3 | 58.7 | 66.8 | 17,000 | 8.5 |
| 1-1/8 | 1.07 | 1.22 | 1.34 | 1.81 ±0.13 | 4.25 ±0.25 | 2.62 | 2.88 | 27.2 | 31.0 | 34.0 | 46.0 | 107.9 | 66.5 | 73.2 | 19,000 | 9.5 |
| 1-1/4 | 1.19 | 1.34 | 1.47 | 2.03 ±0.13 | 4.69 ±0.25 | 2.87 | 3.25 | 30.2 | 34.0 | 37.3 | 51.6 | 119.1 | 72.9 | 82.5 | 24,000 | 12 |
| 1-3/8 | 1.31 | 1.46 | 1.62 | 2.25 ±0.19 | 5.25 ±0.25 | 3.25 | 3.5 | 33.3 | 37.1 | 41.1 | 57.1 | 133.3 | 82.5 | 88.9 | 27,000 | 13.5 |
| 1-1/2 | 1.42 | 1.58 | 1.75 | 2.38 ±0.19 | 5.75 ±0.25 | 3.37 | 3.75 | 36.1 | 40.1 | 44.4 | 60.5 | 146.0 | 85.6 | 95.3 | 34,000 | 17 |
| 1-5/8 | 1.54 | 1.71 | 1.87 | 2.62 ±0.19 | 6.25 ±0.25 | 4 | 4.13 | 39.1 | 43.4 | 47.5 | 66.5 | 158.8 | 101.6 | 104.9 | 40,000 | 20 |
| 1-3/4 | 1.66 | 1.95 | 2.15 | 2.88 ±0.19 | 7 ±0.25 | 4.5 | 4.5 | 42.2 | 49.5 | 54.6 | 73.2 | 177.8 | 114.3 | 114.3 | 50,000 | 25 |
| 2 | 1.9 | 2.19 | 2.4 | 3.25 ±0.19 | 7.75 ±0.5 | 5.25 | 5.25 | 48.3 | 55.6 | 61.0 | 82.5 | 196.8 | 133.3 | 133.3 | 70,000 | 35 |
| 2-1/4 | 2.14 | 2.44 | 2.65 | 3.88 ±0.19 | 9.25 ±0.5 | 5.5 | 5.75 | 54.4 | 62.0 | 67.3 | 98.6 | 234.9 | 139.7 | 146.0 | 80,000 | 40 |
| 2-1/2 | 2.38 | 2.68 | 2.9 | 4.12 ±0.25 | 10.5 ±0.5 | 6.75 | 6.25 | 60.5 | 68.1 | 73.7 | 104.6 | 266.7 | 171.4 | 158.8 | 110,000 | 55 |
| 2-3/4 | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 120,000 | 60 |
| 3 | 2.85 | 3.17 | 3.4 | 5 ±0.25 | 13 ±0.75 | 7.37 | 6.75 | 72.4 | 80.5 | 86.4 | 127.0 | 330.2 | 187.2 | 171.4 | 170,000 | 85 |
| 3-1/2 | 3.32 | 3.66 | 3.9 | 5.25 ±0.25 | 15 ±0.75 | 9 | 8.5 | 84.3 | 93.0 | 99.1 | 133.3 | 381.0 | 228.6 | 215.9 | 240,000 | 120 |
| 4 | 3.8 | 4.14 | 4.4 | 5.5 ±0.25 | 14.5 ±0.75 | 10.5 | 9.5 | 96.5 | 105.2 | 111.8 | 139.7 | 368.3 | 266.7 | 241.3 | 300,000 | 150 |
Nominal size 2-3/4 in has a working load limit row in Table VIII but no row in Table IX. The dimension cells are left empty; nothing is interpolated from the neighbouring sizes.
The value in the working load limit column is the specification's own. For 20 of the 23 sizes it was independently cross-checked against a vendor table stated to meet the same type, class and grade; those rows say so.
Grade B (high strength) is outside the covered range of this chart and is not dimensioned here. Its working load limit appears as a reference column on the index page.
What each column means
These are the column headings the specification uses, restated. They are not synonyms: a buyer who substitutes one for another will size the wrong part.
| Column | Meaning in the specification |
|---|---|
| D - Dimension (D), minimum | Dimension (D) (min) - nominal trade size dimension |
| P - Diameter pin (P), minimum | Diameter pin (P) (min) |
| E - Diameter unthreaded eye(s) (E), reference | Diameter unthreaded eye(s) (E) (ref) - reference dimension only |
| W - Width between eyes (W) ± nominal tolerance | Width between eyes (W) +/- nominal tolerance |
| L - Length inside (L) ± nominal tolerance | Length inside (L) +/- nominal tolerance |
| B - Width bow (B), minimum | Width bow (B) (min) - Type IVA only |
| R - Diameter outside eye (R), maximum | Diameter outside eye (R) (max) |
Screw pin, or bolt, nut and cotter
Both classes are inside the covered range and share the dimensions on this page. The difference is how the pin is retained, which is what decides the class to specify; the rated load in this standard does not change with it.
Class 2 - screw pin
A single threaded pin, assembled and removed by hand with no separate fastener to lose. Suits a shackle that is opened and closed repeatedly, and connections that are taken down between lifts.
Class 3 - bolt, nut and cotter
A bolt retained by a nut and a cotter pin, so the pin cannot back out under vibration and there is a locking device for an inspector to see. The usual choice for a semi-permanent connection and for repeated lifting service.
Class 1 (round pin and cotter) is outside this chart. The specification states that it is intended for general use except overhead lifting, which is why it is not charted alongside Class 2 and Class 3.
Worked example
Reading a row end to end, and checking it against a second source.
- Find the nominal size row. For 1/2 in, the working load limit is 4,000 lbf, which is 2 short ton at 2000 lbf to the short ton.
- Read the dimensions in the same row rather than converting the trade size: minimum D 0.48 in, minimum pin diameter P 0.61 in, width between eyes W 0.81 ±0.13 in, inside length L 1.88 ±0.13 in, outside eye diameter R 1.38 in, bow width B 1.18 in. Millimetre columns are given beside each inch column.
- Convert to millimetres only if the drawing is metric. Minimum pin diameter 0.61 in x 25.4 = 15.5 mm - this is a minimum, so the supplier has to meet it, not approximate it.
- Compare the load figure against a second source. For 1/2 in the same type, class and grade, the vendor tables used as a cross-check state the same 2 short ton working load limit, which is what the row above shows.
Covered range
- Type IVA (Anchor shackles), Class 2 and Class 3, Grade A.
- Nominal sizes 3/16 in through 4 in - the 23 sizes the specification lists for this type.
- Dimensions from Table IX, page 20 of the source document; working load limit from Table VIII.
- Class 1 and Grade B are outside the covered range.
- The dimension table in this revision covers Class 1, Class 2 and Class 3 together, so one row per nominal size is correct for both classes charted here.
- Nominal size 2-3/4 in carries no dimension row and is listed as not tabulated rather than estimated.
- The trade names bow and D (dee) are commercial aliases, not the specification's categories, and are not treated as equivalent here.
- The revision named above is the one shown as active when this chart was extracted. The source document instructs readers to verify the version before use.
Basis and sources
How the figures are read
- Dimensions are transcribed from Table IX of RR-C-271H w/ Amendment 1, page 20, exactly as printed: minimum values stay minimums, reference values stay reference values, and the tolerances on W and L are carried into the table rather than being dropped.
- Working load limit is joined from Table VIII on nominal size D. Proof load is 2.2 x the working load limit and minimum breaking strength is 5 x the working load limit, from the same table.
- The dimension table is not class-specific in this revision, so a single row serves Class 2 and Class 3.
- Millimetre columns are a straight conversion at 1 in = 25.4 mm and are not normative; where the specification is the authority, use the inch values.
References
- RR-C-271H w/ Amendment 1, Chains and Attachments, Carbon and Alloy Steel, 3 January 2022 - Table IX, page 20
- RR-C-271H w/ Amendment 1 - Table VIII, mechanical properties, page 17
- RR-C-271H w/ Amendment 1, section 6.1.3 - intended use of Class 1 against Class 2 and Class 3 shackles, page 40
- Vendor tables for the same type, class and grade, used as independent second-source instances only; the figures published here are the specification's
Cite this chart
YAXIIO. Anchor Shackle Size Chart: RR-C-271H Type IVA Dimensions. https://www.yaxiio.com/en/tools/shackle-size-chart/anchor (accessed 2026-10-29).
Free to cite and embed — attribution required: “YAXIIO” + a link to this page.
Frequently asked questions
What is the difference between the D, P, E, W, L, B, R columns?
Each is a different measurement of the same shackle. D is the nominal body dimension tied to the trade size, P is the pin diameter, E is the unthreaded eye diameter and is given for reference only, W is the width between the eyes, L is the inside length, R is the outside eye diameter, and B is the bow width, which the Type IVA table publishes and the Type IVB table does not. Substituting one for another is how a shackle ends up undersized: a pin chosen by trade size rather than by P, for instance, will not fit the eye it has to pass through.
Why is there no B column on the chain shackle page?
Because the specification does not publish one for Type IVB. The bow-width column belongs to the anchor type, whose wider body is the point of the shape. The chain page therefore runs D, P, E, W, L and R, and the absent column is a property of the standard rather than a gap in this chart.
Can I use E as a clearance dimension?
Only with care. E is marked reference in the specification, which means it is given for information rather than as a requirement, and it is not the dimension a pin or a wire rope passes through in normal use. Size the connection from P, W and L, and treat E as a shape indicator.
Which columns carry a tolerance and which are limits?
W and L are nominal values with a stated tolerance, so a part can be above or below the printed figure within that band. D, P, B and R are minimums or maximums and have no band: the printed value is the limit a supplier has to respect. In this chart the tolerance is printed inside the cell for W and L, and the column heading says min, max or ref for the rest.
Why is 2-3/4 in listed as not tabulated?
The specification gives that nominal size a working load limit row but no dimension row for this type. Rather than interpolating between the neighbouring sizes, or copying a figure from another type, the cells are left empty and the row is labelled. An empty cell here means the standard does not publish the figure, not that the size is unrated.
Is the working load limit on this page the same as the one marked on a shackle I buy?
It should be, if the product is made to this type, class and grade, but the marking on the product governs. A vendor may also certify to a different standard altogether, in which case the figures will differ for reasons that have nothing to do with transcription. This page publishes the specification's values and names them as such; confirm a specific product against its own documentation.
Related charts
The two types have different dimension tables, so each is published on its own page. The working load limit table is shared and lives on the index page.
Need shackles to this specification?
Send the nominal size, class and grade and we will quote against RR-C-271H: state the type (anchor or chain), the class (screw pin, or bolt, nut and cotter), the nominal size, the quantity and any finish or test-certificate requirement.
Request a quoteRelated References
Shackle Size Chart
Working load limit by nominal size for both types, with the vendor cross-check recorded row by row.
Chain Shackle Size Chart
Type IVB dimensions, for the shape built to take a straight pull.
Bolt Size Chart
Metric and inch bolt sizes with head dimensions, for the fasteners a bolted lifting assembly is built from.
Figures are transcribed from RR-C-271H w/ Amendment 1 as published on ASSIST and are given for reference and comparison. The working load limit of a specific product is set by that product's own documentation and markings, which govern in use. This page is not a substitute for the standard, for a lift plan, or for a competent person's assessment.
Type {rrType}, Grade A, Class 2 and Class 3, nominal sizes {sizeMin} in to {sizeMax} in. Dimensions from {geomTable} (page {geomPage}); working load limit from Table VIII. Millimetre columns are conversions, not normative values.