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AN525-416R18
Aeronautical Standard Machine Screw
Description
Washer Head Machine Screw
Specifications
| Country of Origin | USA |
|---|---|
| Extended Washer Diameter | 0.490 inches minimum and 0.510 inches maximum |
| Extended Washer Thickness | 0.028 inches minimum and 0.033 inches maximum |
| Fastener Length | 1.094 inches minimum and 1.156 inches maximum |
| Head Diameter | 0.427 inches minimum and 0.447 inches maximum |
| Head Height | 0.096 inches minimum and 0.106 inches maximum |
| Head Style | Round extended washer |
| Internal Drive Style | Cross recess type 1 |
| Length | 1 5/32 |
| Material | Steel |
| Min. Tensile Strength (psi) | 125000 pounds per square inch |
| NIIN | 00-282-0138 |
| NSN | 5305-00-282-0138 |
| Screw Material | Steel comp 8630 or steel comp 4037 |
| Screw Material Specification | Mil-s-6050 mil spec 1st material response or ams 6300 assn std 2nd material response |
| Screw Surface Treatment | Cadmium or zinc |
| Screw Surface Treatment Specification | Qq-p-416 fed spec 1st treatment response or qq-z-325 fed spec 2nd treatment response |
| Sold In | Per Package |
| Thread Class | 3a |
| Thread Diameter | 0.250 |
| Thread Direction | Right-hand |
| Thread Length | 0.299 inches minimum and 0.453 inches maximum |
| Thread Qty | 28 |
| Thread Qty Per Inch (tpi) | 28 |
| Thread Series Designator | UNF |
| Thread Size | 1/4 |
| Weight | 0.02 lb |
Other sizes
Parts that share this base number, ordered by size. Always verify the full specification before substituting.
Cross-reference
Similar parts
Parts with matching key dimensions — often from a different standards family. Candidates for comparison only; verify the full specification before substituting.
- AN525-416R24 AN 1/4-28 · 0.073 in · Round extended washer · Steel
- AN525-416R28 AN 1/4-28 · 0.073 in · Round extended washer · Steel
- AN525-416R32 AN 1/4-28 · 0.073 in · Round extended washer · Steel
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Catalog data updated 2026-07-05. Report a data error