Cross reference · ESNA · Plate self-locking nut
F18421 cross referenceSPS F18421L, Howmet F49249E, NAS1791C, Boeing ST3M
F18421 is a ESNA plate self-locking nut series on 7 government stock numbers. Its closest equivalents are SPS F18421L, Howmet F49249E, NAS1791C, Boeing ST3M. Each one is labeled with how strong the evidence is.
- Issued by ESNA
- Item Plate self-locking nut
- Stock numbers 7
- Equivalents 8
- DLA paid $1.01 to $9.40
Equivalents in the government catalog
Catalog-only listings need engineering approval before you substitute.
Manufacturers
- F18421LSPS TechnologiesCatalog only, needs approvalon 7 of 7 stock numbers, 7 sizes
- F49249EHowmet Fastening SystemsCatalog only, needs approvalon 7 of 7 stock numbers, 8 sizes
- NS202041SPS TechnologiesCatalog only, needs approvalon 7 of 7 stock numbers, 7 sizes
- F49249Howmet Fastening SystemsCatalog only, needs approvalon 4 of 7 stock numbers, 4 sizes
1 more on one stock number each: LACR53M
- LACR53MHowmet Fastening SystemsCatalog only, needs approvalon 1 of 7 stock numbers
Standards
- NAS1791CNASCatalog only, needs approvalon 7 of 7 stock numbers, 7 sizes
Airframer and OEM drawings
Plus 3 reference numbers whose issuer SpecLok does not identify (distributors and catalog agencies are not named).
Get quotes for F18421
Cited equivalents go on the request as acceptable alternates. Catalog-only listings do not.
Install tooling
SpecLok has no catalog family for F18421. Tooling for the equivalents:
None of the equivalents is in the SpecLok catalog yet.
What the government paid
DLA awards on 4 of 7 stock numbers, 33 awards from 2023-01-13 to 2026-06-22.
Latest award per stock number: $1.01 to $9.40 each.
DLA production lead time: 155 days.
Per size in the table below.
DLA prices at DLA quantities, not a quote.Source
DLA award prices at DLA quantities and terms, not a commercial quote. Each award may bundle packaging, delivery and inspection terms that a commercial buy does not. Vendors are shown by CAGE code only.
Source: DLA FOIA Electronic Reading Room ↗, public FOIA releases. Files: 2023ContHist.zip/2023ContractHistory.txt, 2024ContHist.zip/2024ContractHistory.txt, contracthist2025.zip/contracthist2025.txt, 2026-09-16-1038_contracthist.zip/2026-09-16-1038_contracthist.txt.
Sizes by maker
| NSN | F18421 | F18421L | F49249E | NAS1791C | ST3M | 3929AS | Last DLA price |
|---|---|---|---|---|---|---|---|
| 5310-00-379-4633 | F18421-1-3 | F18421L1-3 | F49249E3-1 | NAS1791C3-1 | ST3M443-3A1 | 3929AS1225-3A1 | |
| 5310-00-283-4618 | F18421-1-4 | F18421L1-4 | F49249E4-4-1 | NAS1791C4-1 | ST3M443-4A1 | 3929AS1225-4A1 | $2.07 2024-12 |
| 5310-00-143-0358 | F18421-2-3 | F18421L2-3 | F49249E3-2 | NAS1791C3-2 | ST3M443-3A2 | 3929AS1225-3A2 | $1.01 2025-10 |
| 5310-00-283-4619 | F18421-2-4 | F18421L2-4 | F49249E4-2 | NAS1791C4-2 | ST3M443-4A2 | ||
| 5310-01-090-6367 | F18421-4-4 | F18421L4-4 | F49249E4-4 | NAS1791C4-4 | ST3M443-4A-4 | $2.45 2026-06 | |
| 5310-00-283-4635 | F18421-4-5 | F18421L4-5 | F49249E5-4 | NAS1791C5-4 | ST3M443-5A4 | $9.40 2023-11 | |
| 5310-00-283-7522 | F18421-6-4 | F18421L6-4 | F49249E4-6 | NAS1791C4-6 | ST3M443-4A6 |
Each row is one National Stock Number and the part numbers DLA FLIS lists on it, as written there. A blank means FLIS lists no part in that series on the stock number, not that the size does not exist.
Sources and how to read this page.Details
Reference numbers the Federal Logistics Information System records against the same National Stock Number. A supply-catalog cross-reference, not an engineering-approved interchangeability: confirm against the controlling drawing or spec before substituting. Only equivalents marked cited have a manufacturer or government document, linked with each.
Source: DLA Federal Logistics Information System, via DLA PUB LOG ↗ (FLIS Data Electronic Reading Room ↗), data as of 2025-03-18 (March 2025 snapshot). Federal supply class 5310 Nuts and washers. Issuer names are SpecLok's reading of the filing CAGE code; distributors are not named. Compiled 2026-10-02.
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