Part Number
Setscrew · MS (Military Standard) · NSN 5305-00-877-8743
| Part number | MS51021-12 |
|---|---|
| Specification family | MS (Military Standard) |
| Item name | Setscrew |
| Alternate references | AN565AC4H5-MS51021-12; AN565AC4H5 |
| Unit of issue | EA |
| Cross-referenced NSN | 5305-00-877-8743 |
| Federal Supply Class (FSC) | 5305 — Screws |
| Unit price (USD) | $31.55 |
| Country of origin | Türkiye (Turkey) |
| Lead time | Within 90 days of order |
| Minimum order | May apply — confirm on quote |
| Documentation | Source documentation provided on all orders |
Characteristics decoded from the federal cataloging record for this setscrew. Confirm controlling dimensions against your drawing or standard sheet before ordering.
| Fastener Length | 0.312 Inches Nominal |
|---|---|
| Head Style | Headless (Setscrew) |
| Material | Steel Comp 302 Overall Or Steel Comp 303 Overall Or Steel Comp 304 Overall Or Steel Comp 316 Overall |
| Nominal Thread Diameter | 0.112 Inches |
| Surface Treatment | Passivate Overall |
| Thread Class | 3A |
| Thread Quantity Per Inch | 40 |
| Thread Series Designator | Unc |
Externally threaded fasteners designed to be turned to assemble or adjust parts, including machine screws, cap screws, socket-head cap screws, set screws, self-tapping and thread-forming screws. This is the largest single class in the U.S. supply system and covers a vast range of thread sizes, drive types, head styles, and materials.
Reading the part number. MS51021-12 breaks down as MS51021 — the Military Standard sheet that fixes the part's design — plus the dash/suffix code 12, which selects the exact size, material, or finish variant from the tables on that standard. Two parts sharing the MS51021 base are the same design in different variants.
Price in context. Across the 2,357 items we currently stock in FSC 5305 (Screws), published unit prices run from $0.03 to $14,752.17. At $31.55, this item sits well above the class median of $10.52 — typical of assemblies and higher-value line items in this class.
Who orders MS51021-12. Aircraft owners and MRO shops replacing standard hardware, machine shops and OEMs filling a bill of materials, and government contractors sourcing against NSN 5305-00-877-8743. You can order by part number or by stock number — it is the same item, the same published price, and the same quote form.
Applicable standards. ASME B18.3 / B18.6.3, MIL-DTL / NASM / MS and AN series, ISO metric threads; common materials include carbon and alloy steel, 300/400-series stainless, and A2/A4 stainless per ISO 3506.
Need this part modified, or a similar part made to your print? See our U.S.-based CNC machining services and aerospace machining capability.
Country of origin: Türkiye (Turkey). Turkey is a NATO ally and a normal-trade-relations partner of the United States, and Turkish-origin end items are eligible for a wide range of U.S. federal and DLA procurements.
TAA note: Turkey is not a Trade Agreements Act (TAA) designated country, so these items are generally not eligible for TAA-covered solicitations. They are offerable under the Buy American Act and many non-TAA DLA buys. Buyers are responsible for confirming the origin requirements of their specific solicitation.
Full country-of-origin and source documentation is provided with every order. Fulfillment within 90 days of order. Minimum order may apply.
Items are supplied as stock mil-spec / commercial hardware with source documentation and country-of-origin paperwork on every order. Parts are not supplied with an FAA Form 8130-3 airworthiness tag unless expressly stated on the quote. Buyers installing hardware on certificated aircraft are responsible for acceptance under their own maintenance program, repair station procedures, or owner/operator authority.
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