Part Number
Machine Bolt · Military specification (MIL series) · NSN 5306-01-507-7162
| Part number | MIL-B-857 |
|---|---|
| Specification family | Military specification (MIL series) |
| Item name | Machine Bolt |
| Unit of issue | EA |
| Cross-referenced NSN | 5306-01-507-7162 |
| Federal Supply Class (FSC) | 5306 — Bolts |
| 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 machine bolt. Confirm controlling dimensions against your drawing or standard sheet before ordering.
| Fastener Length | 1.250 Inches Nominal |
|---|---|
| Hardness Rating | 80.0 Rockwell B Minimum Overall |
| Head Style | Hexagon |
| Material | Nickel Alloy 400 Overall |
| Nominal Thread Diameter | 0.500 Inches |
| Thread Series Designator | Unc |
| Thread Quantity Per Inch | 13 |
| Thread Class | 2A |
Externally threaded fasteners designed to be paired with a nut and used to hold two or more parts together, including hex bolts, structural bolts, eye bolts, U-bolts, plow bolts, and close-tolerance bolts.
Reading the part number. MIL-B-857 cites military specification MIL-B-857. A spec citation covers every item made to that document, so the NSN — not the spec number — is what uniquely identifies this machine bolt; the cross-referenced stock number below is the exact item.
Price in context. Across the 1,133 items we currently stock in FSC 5306 (Bolts), published unit prices run from $0.15 to $15,770.70. At $31.55, this item sits above the class median of $21.03.
Who orders MIL-B-857. Aircraft owners and MRO shops replacing standard hardware, machine shops and OEMs filling a bill of materials, and government contractors sourcing against NSN 5306-01-507-7162. 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 B18.2.1, SAE J429 grades, ASTM A325/A490, MS/AN/NAS series; carbon, alloy, and corrosion-resistant steels with a range of plating and coating options.
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) — a DFARS qualifying country. Türkiye is a NATO ally with a reciprocal defense procurement agreement with the U.S. Department of Defense, making it a qualifying country under DFARS 225.003. On DoD and DLA solicitations, qualifying-country end products are evaluated without Buy American price penalties — they compete on par with domestic product — and DoD trade-agreements clauses (DFARS 252.225-7021) expressly accept qualifying-country end products.
Dollar thresholds. The Trade Agreements Act only applies to supply contracts at or above $174,000 (the WTO GPA threshold effective March 2026); below that — where the vast majority of hardware buys fall — the TAA does not apply at all. The main exclusion is civilian-agency solicitations at or above that threshold that restrict award to TAA designated-country products (Türkiye is not TAA-designated). 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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