Part Number
Round Self-Locking Nut · OEM / vendor part number · NSN 5310-01-187-7971
| Part number | SL 7155 |
|---|---|
| Specification family | OEM / vendor part number |
| Item name | Round Self-Locking Nut |
| Unit of issue | EA |
| Cross-referenced NSN | 5310-01-187-7971 |
| Federal Supply Class (FSC) | 5310 — Nuts and Washers |
| Unit price (USD) | $70.09 |
| 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 round self-locking nut. Confirm controlling dimensions against your drawing or standard sheet before ordering.
| Material | Steel Comp 4130 Overall |
|---|---|
| Surface Treatment | Oxide Overall |
| Thread Class | 3B |
| Thread Quantity Per Inch | 18 |
Internally threaded fasteners (hex nuts, lock nuts, castle nuts, wing nuts, self-locking nuts) and washers (flat, lock, spring, and special washers) used to distribute load and secure threaded assemblies.
Reading the part number. SL 7155 is a vendor part number for this round self-locking nut. If your documentation lists a different reference for the same item, include it on the quote and we will confirm the cross-reference.
Price in context. Across the 1,177 items we currently stock in FSC 5310 (Nuts and Washers), published unit prices run from $0.12 to $68,673.00. At $70.09, this item sits well above the class median of $8.76 — typical of assemblies and higher-value line items in this class.
Who orders SL 7155. Aircraft owners and MRO shops replacing standard hardware, machine shops and OEMs filling a bill of materials, and government contractors sourcing against NSN 5310-01-187-7971. 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 B18.2.2 / B18.16, B18.21 / B18.22, NASM/MS series; steel, stainless, and self-locking (nylon-insert and all-metal) designs.
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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