ASME B18.2.2 Hex Slotted (Castle) Nuts (Inch Series)
ASME B18.2.2 hex slotted (castle) nuts, inch series 1/4 – 1 1/2 in — the slotted hex nut that locks against a cotter pin through a drilled shank, with the collected per-size table: width across flats and corners, thickness, unslotted thickness and slot width limits.
Last updated: 2026-11
Specifications
The hex slotted nut — the inch-series castle nut of ASME B18.2.2 — is the mechanical answer to nut loosening on a rotating or vibrating shaft: hex nut geometry with slots cut across the top face, mated with a bolt or shaft whose shank is drilled for a cotter pin. Tighten, align the nearest slot with the cross-hole, run the cotter pin through, bend its prongs, and the nut can rotate only as far as the slots allow before the pin stops it — positive, inspectable, reusable retainment that no thread-locking compound matches for high-vibration inch-system machinery. The collected table runs 1/4 through 1 1/2 in and prints the two thickness dimensions that make this nut work: full thickness H (the slotted height) and unslotted thickness T (the solid hex body below the slots) — the H − T band is the slot depth the cotter pin and its prongs live in — plus width across flats F (basic/min/max), across corners G (min/max) and slot width S (min/max, e.g. 0.07–0.10 in at 1/4, 0.37–0.46 at 1 1/2), which sizes the cotter pin (see this catalog's ASME B18.8.1 cotter pin page). The source repeats a partial header fragment after the last data row — noted in the table footer, not data. Property classes, drill sizes for the mating shank and finishes are not tabulated by the collected specification — per RFQ.
| Standard | ASME B18.2.2-2010 — square and hex nuts, inch series (hex slotted nut: slotted hex nut for cotter-pin locking against a drilled shank; "castle nut" usage per the source) |
|---|---|
| Size range | Nominal 1/4 – 1 1/2 in, fourteen sizes (1/4, 5/16, 3/8 … 1 1/2); one geometry row per size |
| Tabulated geometry | Per size: basic major dia. of thread, width across flats F (basic/min/max), width across corners G (min/max), thickness H (basic/min/max), unslotted thickness T (min/max), slot width S (min/max, e.g. 1/4 in: 0.07–0.10; 1 1/2 in: 0.37–0.46) |
| Locking engagement | Slots in the H − T band index with the nearest cross-hole in the drilled shank; cotter pin sized to the S slot-width range (pairs with the ASME B18.8.1 cotter pin page in this catalog) |
| Property classes / finishes | Not tabulated by the collected specification — per RFQ (state grade, shank drill size and finish at quotation) |
| Nominal Size | Basic Major Dia. of Thread | F — Width Across Flats (basic) | F — Min. | F — Max. | G — Width Across Corners Min. | G — Max. | H — Thickness (basic) | H — Min. | H — Max. | T — Unslotted Thickness Min. | T — Max. | S — Width of Slot Min. | S — Max. |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 1/4 | 0.2500 | 7/16 | 0.428 | 0.438 | 0.488 | 0.505 | 7/32 | 0.212 | 0.226 | 0.12 | 0.14 | 0.07 | 0.10 |
| 5/16 | 0.3125 | 1/2 | 0.489 | 0.500 | 0.557 | 0.577 | 17/64 | 0.258 | 0.273 | 0.16 | 0.18 | 0.09 | 0.12 |
| 3/8 | 0.3750 | 9/16 | 0.551 | 0.562 | 0.628 | 0.650 | 21/64 | 0.320 | 0.337 | 0.19 | 0.21 | 0.12 | 0.15 |
| 7/16 | 0.4375 | 11/16 | 0.675 | 0.688 | 0.768 | 0.794 | 3/8 | 0.365 | 0.385 | 0.21 | 0.23 | 0.12 | 0.15 |
| 1/2 | 0.5000 | 3/4 | 0.736 | 0.750 | 0.840 | 0.866 | 7/16 | 0.427 | 0.448 | 0.27 | 0.29 | 0.15 | 0.18 |
| 9/16 | 0.5625 | 7/8 | 0.861 | 0.875 | 0.982 | 1.010 | 31/64 | 0.473 | 0.496 | 0.29 | 0.31 | 0.15 | 0.18 |
| 5/8 | 0.6250 | 15/16 | 0.922 | 0.938 | 1.051 | 1.083 | 35/64 | 0.535 | 0.559 | 0.32 | 0.34 | 0.18 | 0.24 |
| 3/4 | 0.7500 | 1 1/8 | 1.088 | 1.125 | 1.240 | 1.299 | 41/64 | 0.617 | 0.665 | 0.38 | 0.40 | 0.18 | 0.24 |
| 7/8 | 0.8750 | 1 5/16 | 1.269 | 1.312 | 1.447 | 1.516 | 3/4 | 0.724 | 0.776 | 0.49 | 0.52 | 0.18 | 0.24 |
| 1 | 1.0000 | 1 1/2 | 1.450 | 1.500 | 1.653 | 1.732 | 55/64 | 0.831 | 0.887 | 0.56 | 0.59 | 0.24 | 0.30 |
| 1 1/8 | 1.1250 | 1 11/16 | 1.631 | 1.688 | 1.859 | 1.949 | 31/32 | 0.939 | 0.999 | 0.61 | 0.64 | 0.24 | 0.33 |
| 1 1/4 | 1.2500 | 1 7/8 | 1.812 | 1.875 | 2.066 | 2.165 | 1 1/16 | 1.030 | 1.094 | 0.67 | 0.70 | 0.31 | 0.40 |
| 1 3/8 | 1.3750 | 2 1/16 | 1.994 | 2.062 | 2.273 | 2.382 | 1 11/64 | 1.138 | 1.206 | 0.78 | 0.82 | 0.31 | 0.40 |
| 1 1/2 | 1.5000 | 2 1/4 | 2.175 | 2.250 | 2.480 | 2.598 | 1 9/32 | 1.245 | 1.317 | 0.82 | 0.86 | 0.37 | 0.46 |
Materials
- Material, property class and finish specified per RFQ — state the mating bolt (drilled shank required) and cotter pin material 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 B18.2.2 Hex Slotted (Castle) Nuts (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 quantity is 10,000 pieces. Stock items run 3–7 days. Quantities or variants outside the standard range are confirmed at 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 the cotter pin and the shank hole for a slotted nut?
Three columns on the collected table work together, plus one dimension the nut table cannot print. The slot width S range (min/max) per nut size tells you the cotter pin's cross-section window: a 3/8 in slotted nut takes a pin with a 0.12–0.15 in slot fit, which lands in the ASME B18.8.1 cotter pin size ladder — the gage-hole column on that table then gives the matching cross-hole diameter (the 3/8 cotter pin's gage is 0.375 in). The unslotted thickness T matters for the second check: the shank's cross-hole must sit inside the slot band — above the T plane, below the H top — so when the nut is torqued to spec the nearest slot aligns with a hole drilled at that height. Practical sequence: drill the shank at the hole diameter the cotter pin's gage column prints; assemble and torque the nut to its running specification; check which slot aligns — slotted nuts are designed so some slot always lands within a light additional turn of the hole; insert the cotter pin, bend the prongs over the nut face, and the lock is positive and visually inspectable. What the tables deliberately leave out: property class of the nut, the torque value itself and the cotter pin material — all RFQ lines, since they depend on the joint's load and environment, not the geometry.
What is the MOQ and lead time for this nut type?
The minimum order quantity is 10,000 pieces. Stock items ship in 3–7 days; non-stock items are confirmed at quotation. Common sizes in this nut type are widely stocked; confirm the exact schedule against quantity and size mix at quotation.
Request a Quote
Get factory-direct pricing from the manufacturer.
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