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BACS21Y2FR — STUD ASSEMBLY,TURNLOCK FASTENER

✓ Government record, cited
— · BOLT SCREW
PRODUCT OVERVIEW

BACS21Y2FR: STUD ASSEMBLY,TURNLOCK FASTENER.

STUD ASSEMBLY,TURNLOCK FASTENER. Key specifications include diameter: 0.251 INCHES MINIMUM AND 0.256 INCHES MAXIMUM IN, material: STEEL EJECTOR SPRING, drive_type: CROSS RECESS, eyelet_length: 0.328 INCHES NOMINAL IN, stud_head_height: 0.069 INCHES MINIMUM AND 0.076 INCHES MAXIMUM IN, surface_treatment: CADMIUM AND CHROMATE OVERALL. This part is cataloged in the U.S.

Government catalog under NSN 5325-00-701-9678, indicating validated use in U.S. government and defense logistics supply chains. Available through authorized enterprise resellers and TPM (Third Party Maintenance) channels.

Verify compatibility with your specific system configuration before ordering.

WHERE IT FITS
BACS21Y2FR
NSN: 5325-00-701-9678
FSC: 5325 — Fastening Devices
CAGE: 81205 — THE BOEING COMPANY DIV DEFENSE (USA)
SPECIFICATIONS
diameter0.251 INCHES MINIMUM AND 0.256 INCHES MAXIMUM IN
materialSTEEL EJECTOR SPRING
drive_typeCROSS RECESS
eyelet_length0.328 INCHES NOMINAL IN
stud_head_height0.069 INCHES MINIMUM AND 0.076 INCHES MAXIMUM IN
surface_treatmentCADMIUM AND CHROMATE OVERALL
stud_assembly_styleSTUD ASSEMBLY
eyelet_outside_diameter0.244 INCHES MINIMUM AND 0.250 INCHES MAXIMUM IN
turnlock_stud_head_styleSTUD HEAD
material_accommodated_thickness0.060 INCHES MINIMUM AND 0.089 INCHES MAXIMUM IN
surface_treatment_document_and_classificationQQ-P-416,TY2,CL 2 FED SPEC SINGLE TREATMENT RESPONSE OVERALL
distance_from_engaging_member_to_largest_bearing_surface_of_head0.491 INCHES MINIMUM AND 0.501 INCHES MAXIMUM IN
NSN5325-00-701-9678
COMPONENT DIAGRAM
BOLT / SCREW — THREAD VERIFICATION REQUIRED Hex HEAD LENGTH: — THREAD: — × — MATERIAL: — PN: BACS21Y2FR · OEM ⚠ VERIFY BEFORE ORDERING Verify thread pitch before ordering — metric (M8×1.25) ≠ imperial (5/16-18). Wrong thread = wrong part. Grade/class stamped on bolt head determines tensile strength ✓ BROKER TIP Grade/class stamped on head determines tensile strength. Grade 8 > Grade 5 > Grade 2. Always confirm head marking matches specification requirement PARTSTABLE TECHNICAL DRAWING — NOT TO SCALE
KEY FEATURES
•
SURFACE TREATMENT DOCUMENT AND CLASSIFICATION: QQ-P-416,TY2,CL 2 FED SPEC SINGLE TREATMENT RESPONSE OVERALL
•
EYELET OUTSIDE DIAMETER: 0.244 INCHES MINIMUM AND 0.250 INCHES MAXIMUM IN
•
DRIVE TYPE: CROSS RECESS
•
MATERIAL ACCOMMODATED THICKNESS: 0.060 INCHES MINIMUM AND 0.089 INCHES MAXIMUM IN
•
DIAMETER: 0.251 INCHES MINIMUM AND 0.256 INCHES MAXIMUM IN
•
STUD HEAD HEIGHT: 0.069 INCHES MINIMUM AND 0.076 INCHES MAXIMUM IN
•
DISTANCE FROM ENGAGING MEMBER TO LARGEST BEARING SURFACE OF HEAD: 0.491 INCHES MINIMUM AND 0.501 INCHES MAXIMUM IN
•
TURNLOCK STUD HEAD STYLE: STUD HEAD
TECHNICAL CHARACTERISTICS
SURFACE TREATMENT DOCUMENT AND CLASSIFICATIONQQ-P-416,TY2,CL 2 FED SPEC SINGLE TREATMENT RESPONSE OVERALL
EYELET OUTSIDE DIAMETER0.244 INCHES MINIMUM AND 0.250 INCHES MAXIMUM IN
DRIVE TYPECROSS RECESS
MATERIAL ACCOMMODATED THICKNESS0.060 INCHES MINIMUM AND 0.089 INCHES MAXIMUM IN
DIAMETER0.251 INCHES MINIMUM AND 0.256 INCHES MAXIMUM IN
STUD HEAD HEIGHT0.069 INCHES MINIMUM AND 0.076 INCHES MAXIMUM IN
DISTANCE FROM ENGAGING MEMBER TO LARGEST BEARING SURFACE OF HEAD0.491 INCHES MINIMUM AND 0.501 INCHES MAXIMUM IN
TURNLOCK STUD HEAD STYLESTUD HEAD
SURFACE TREATMENTCADMIUM AND CHROMATE OVERALL
MATERIALSTEEL COMP 4037 STUD
OTHER ITEMS IN FSC 5325 — Fastening Devices
Items in the same Federal Supply class. No interchangeability or substitution relationship is implied.
5325-00-000-1884 5325-00-000-9988 5325-00-001-1567 5325-00-001-2043 5325-00-001-3842 5325-00-001-3858 5325-00-001-3871 5325-00-001-4317
SUBSTITUTES & CROSS-REFERENCES 5
1127004-2Same NSN cross-reference
Same NSN cross-reference
Also cataloged under this NSN
27S3-2Same NSN cross-reference
Same NSN cross-reference
Also cataloged under this NSN
27S3-02Reference document
Same NSN cross-reference
Reference document — Advisory reference — outside the item-of-supply concept
18509573-3Same NSN cross-reference
Same NSN cross-reference
Also cataloged under this NSN
BACS21EE2FRReference document
Same NSN cross-reference
Reference document — Vendor item drawing reference
LIFECYCLE
NSN statusActive· U.S. Government catalog
Acquisition advice: Insurance item — stocked against contingency demandNo demilitarization required
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FREQUENTLY ASKED QUESTIONS
What is BACS21Y2FR?
BACS21Y2FR is a STUD ASSEMBLY,TURNLOCK FASTENER.
What parts can replace BACS21Y2FR?
There are 5 known substitutes for BACS21Y2FR: 1127004-2, 27S3-2, 27S3-02 and 2 more. Substitute compatibility should be verified for your specific system.
What is the NSN for BACS21Y2FR?
BACS21Y2FR is cataloged in the U.S. Government catalog under NSN 5325-00-701-9678. This indicates validated use in U.S. government and defense supply chains.
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PartsTable Design LLC · partstable.com
U.S. Government catalog: edition PUBLOGDVD v12.0.0 (OCT 2026), edition date 2026-10-01, retrieved 2026-10-18.
PartsTable commercial catalog: edition Unified commercial catalog snapshot through 2026-09-28, edition date not on file, retrieved 2026-09-28.