ASME B18.8.1 Clevis Pins (Inch Series)
ASME B18.8.1 clevis pins, inch series 3/16 – 1 in — the single-shear hinge pin with a low flat head, cotter hole and chamfered point, with the collected per-size tables: shank, head and hole geometry plus recommended lengths and cotter pin sizes.
Last updated: 2026-11
Specifications
The clevis pin is a hinge in a part: a low-profile flat head on one end, a cross-hole for a cotter pin near the other, and a chamfered point that finds the hole — made to pivot in a clevis, yoke or linkage where the pin is loaded in single shear and removed regularly for service. ASME B18.8.1 tabulates the inch-series pin in two collected tables. The first carries the geometry per size from 3/16 through 1 in: shank diameter A (max/min — the body runs slightly under basic, e.g. 0.496/0.491 at the 1/2 in pin, a running fit in a drilled hole), head diameter B and height C (the head is deliberately shallow — 0.63–0.61 in diameter by 0.16–0.14 in height at 1/2 in — so it sits over the clevis ear without adding pivot offset), head chamfer D, and cotter hole diameter E (max/min: 0.088–0.073 at 3/16 up to 0.182–0.167 at 1 in). The second table is the length-selection table: point diameter F, recommended pin length G (basic/max/min, from 0.58 at 3/16 to 2.41 at 1 in — intended for a standard clevis without spacers, with other lengths recommended to fall at 0.06-inch increments per the source's Note 1), the source's head-to-hole reference cells (carried verbatim — see the table footnote on the two-cells-under-three-columns source quirk), and the recommended cotter pin size per pin, which pairs directly with this catalog's ASME B18.8.1 cotter pin page (1/16 at the small sizes, 5/32 at 3/4 and up). Materials and finishes are not tabulated by the collected specification — per RFQ.
| Standard | ASME B18.8.1-1994 — clevis pins and cotter pins, inch series (clevis pin: low flat head, cotter cross-hole, chamfered point for single-shear pivot duty) |
|---|---|
| Size range | Nominal 3/16 – 1 in basic pin diameter, ten sizes; one geometry row per size in each table |
| Shank and head geometry | Shank dia. A slightly under basic (1/2 in: 0.496 max / 0.491 min — running fit); head dia. B (1/2 in: 0.63–0.61) and head height C (0.16–0.14); head chamfer D ± 0.01 |
| Cotter hole | Hole dia. E (max/min): 0.088–0.073 at 3/16 → 0.182–0.167 at 1 in; recommended cotter pin sizes 1/16 (3/16, 1/4) → 3/32 (5/16–7/16) → 1/8 (1/2, 5/8) → 5/32 (3/4 – 1) — pairs with the ASME B18.8.1 cotter pin page in this catalog |
| Length selection | Recommended length G basic 0.58 (3/16) → 2.41 (1 in), tabulated for a standard clevis without spacers; other lengths per source Note 1: limited where possible to nominal lengths in 0.06-inch increments; point dia. F runs 0.15 → 0.93 |
| Materials / finishes | Not tabulated by the collected specification — per RFQ (state material, shear load and environment at quotation) |
| Nominal Size | Basic Pin Dia. | A — Shank Dia. (max) | A (min) | B — Head Dia. (max) | B (min) | C — Head Height (max) | C (min) | D — Head Chamfer (± 0.01) | E — Hole Dia. (max) | E (min) |
|---|---|---|---|---|---|---|---|---|---|---|
| Max. | Min. | Max. | Min. | Max. | Min. | ± 0.01 | Max. | Min. | ||
| 3/16 | 0.188 | 0.186 | 0.181 | 0.32 | 0.30 | 0.07 | 0.05 | 0.02 | 0.088 | 0.073 |
| 1/4 | 0.250 | 0.248 | 0.243 | 0.38 | 0.36 | 0.10 | 0.08 | 0.03 | 0.088 | 0.073 |
| 5/16 | 0.312 | 0.311 | 0.306 | 0.44 | 0.42 | 0.10 | 0.08 | 0.03 | 0.119 | 0.104 |
| 3/8 | 0.375 | 0.373 | 0.368 | 0.51 | 0.49 | 0.13 | 0.11 | 0.03 | 0.119 | 0.104 |
| 7/16 | 0.438 | 0.436 | 0.431 | 0.57 | 0.55 | 0.16 | 0.14 | 0.04 | 0.119 | 0.104 |
| 1/2 | 0.500 | 0.496 | 0.491 | 0.63 | 0.61 | 0.16 | 0.14 | 0.04 | 0.151 | 0.136 |
| 5/8 | 0.625 | 0.621 | 0.616 | 0.82 | 0.80 | 0.21 | 0.19 | 0.06 | 0.151 | 0.136 |
| 3/4 | 0.750 | 0.746 | 0.741 | 0.94 | 0.92 | 0.26 | 0.24 | 0.07 | 0.182 | 0.167 |
| 7/8 | 0.875 | 0.871 | 0.866 | 1.04 | 1.02 | 0.32 | 0.30 | 0.09 | 0.182 | 0.167 |
| 1 | 1.000 | 0.996 | 0.991 | 1.19 | 1.17 | 0.35 | 0.33 | 0.10 | 0.182 | 0.167 |
| Nominal Size | Basic Pin Dia. | F — Point Dia. (max) | F (min) | G — Pin Length (basic) | G (max) | G (min) | H/J/M — source prints two cells under this three-column span | (second cell) | Recom. Cotter Pin Size |
|---|---|---|---|---|---|---|---|---|---|
| 3/16 | 0.188 | 0.15 | 0.14 | 0.58 | 0.504 | 0.484 | 0.09 | 0.440 | 1/16 |
| 1/4 | 0.250 | 0.21 | 0.20 | 0.77 | 0.692 | 0.672 | 0.09 | 0.628 | 1/16 |
| 5/16 | 0.312 | 0.26 | 0.25 | 0.94 | 0.832 | 0.812 | 0.12 | 0.752 | 3/32 |
| 3/8 | 0.375 | 0.33 | 0.32 | 1.06 | 0.958 | 0.938 | 0.12 | 0.878 | 3/32 |
| 7/16 | 0.438 | 0.39 | 0.38 | 1.19 | 1.082 | 1.062 | 0.12 | 1.002 | 3/32 |
| 1/2 | 0.500 | 0.44 | 0.43 | 1.36 | 1.223 | 1.203 | 0.15 | 1.127 | 1/8 |
| 5/8 | 0.625 | 0.56 | 0.55 | 1.61 | 1.473 | 1.453 | 0.15 | 1.377 | 1/8 |
| 3/4 | 0.750 | 0.68 | 0.67 | 1.91 | 1.739 | 1.719 | 0.18 | 1.628 | 5/32 |
| 7/8 | 0.875 | 0.80 | 0.79 | 2.16 | 1.989 | 1.969 | 0.18 | 1.878 | 5/32 |
| 1 | 1.000 | 0.93 | 0.92 | 2.41 | 2.239 | 2.219 | 0.18 | 2.128 | 5/32 |
- Row 1 (3/16): The source header declares four columns here — H (basic/min), J and M — but prints only two cells per row across that span; both cells are carried verbatim in the two unlabeled columns without assigning them to H, J or M.
Materials
- Material and finish specified per RFQ — clevis pins take single-shear pivot loads and frequent reassembly; state the working load, clevis width and environment with the order
Ordering & documentation
Documents
Shipments are backed by Mill Test Certificate (MTC), Dimensional Report, Salt Spray Test Report on request, with full batch traceability from raw material to finished product. Quality management follows the owner-confirmed compliance list: ISO 9001:2015, RoHS, REACH. Exact document sets are confirmed on the order.
Quotation
- The fastener family (ASME B18.8.1 Clevis Pins (Inch Series)) plus the standard designation from your drawing — DIN / ISO / JIS / ASTM / ANSI, or a drawing for custom parts.
- Size (diameter and length), thread type (metric or inch), property class or grade, and coating or finish.
- Quantity per size and your target delivery date.
- Destination country, and any required documents (for example a mill test certificate) so the quote includes them.
Sample & supply
Minimum order quantities and lead times for this family are confirmed at quotation — send your sizes, grades and quantities on the RFQ and the quote will carry a firm schedule. Sample availability is confirmed with the quotation.
Storage & shipping
Parts are packed for export and shipped factory-direct to buyers in Europe, Asia, the Americas and the Middle East. Store fasteners dry and protected until installation, and keep coated parts in their packaging until use; specific packing and preservation requirements can be stated on the order and confirmed at quotation.
Frequently asked questions
How do I size a clevis pin and its cotter pin for a clevis I already have?
Work the collected tables in three steps. First the shank: match the pin diameter to the clevis bores — the A column shows the pin runs a few thousandths under its basic size (a 1/2 in pin measures 0.496 max / 0.491 min), which is what gives the running fit a clevis hinge needs; drill or ream the clevis bores to the basic size, not to the pin's actual diameter. Second the length: the G column's recommended lengths assume a standard clevis without spacers — if your stack-up includes washers, spacers or a grease fitting, source Note 1's rule is the practical guide: keep the ordered length at a nominal in 0.06-inch increments, and confirm at assembly that the cotter hole sits fully outside the clevis ear so the pin cannot back out against the ear's edge. Third the lock: the last column pairs each pin with its cotter pin — a 3/8 in clevis pin takes a 3/32 cotter pin — and the cotter hole diameter E (0.119–0.104 at 3/8) is the hole the cotter's legs must pass through, which is where this catalog's ASME B18.8.1 cotter pin page picks up: match the cotter's nominal size to the recommended column and check its shank diameter against the E hole, then bend the legs over the pin end. Two RFQ lines the tables deliberately leave open: material and finish (plain carbon, stainless for washdown, hardened only where the shear load demands it — none of that is in the collected chart), and any shear-rating requirement, since ASME B18.8.1 governs geometry, not load.
What is the difference between this clevis pin page and the cotter pin page from the same standard?
ASME B18.8.1 covers both parts, and the two charts are the mating pair, not alternatives. The clevis pin page tabulates the pin: shank, head, point, recommended lengths and the hole that receives its retainment. The cotter pin page (in this catalog) tabulates the retainment: the split pin's own dimensions and the gage hole it is designed to pass through. They connect at exactly the numbers this page carries — the recommended cotter size column (1/16 through 5/32 across the 3/16 – 1 in pin ladder) and the cotter hole diameter E. For quoting, that means one RFQ can cover both: state the pin size, the recommended length (or the 0.06-inch increment custom length), material and finish for both parts, and the cotter comes sized to the pin per the standard. What the pairing does not change: both pages are geometry standards — shear capacity, wear life and material strength are RFQ lines regardless of which chart you are reading.
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What to include in your inquiry
- ✓ Standard and property class (e.g. DIN 912, ISO 4762, class 8.8) — or a drawing for custom parts.
- ✓ Sizes, lengths and thread type (metric or inch).
- ✓ Quantity per size and your target delivery date.
- ✓ Destination country, plus any coating or finish requirement.
- ✓ Any documents you need with the shipment (e.g. mill test certificate) so the quote includes them.
- ✓ Your inquiry goes straight to the factory team by email and gets a reply within 24 hours.
- ✓ Factory-direct pricing
- ✓ Standard and custom specifications
- ✓ Factory-direct export to buyers in Europe, Asia, the Americas and the Middle East
- ✓ Full fastener family support