The Screw,close Tolerance, cataloged under National Stock Number 5305-01-337-0357, is classified within Federal Supply Class 5305 (Screws) of the Hardware and Abrasives group. The manufacturer of record is Hi-Shear Corporation. Government technical data includes 21 specifications, cited from the U.S. Government catalog. The record lists 4 manufacturer part numbers for this item, enabling identification through both NSN and commercial part number lookups. 6 additional reference documents (drawings, advisory and superseded references) are recorded in the U.S. Government catalog. Current acquisition status: Active.
| Parameter | Value |
|---|---|
| NSN | 5305-01-337-0357 |
| Primary Part Number | BACB30MS7R21 |
| Item Name | Screw,close Tolerance |
| FSC / FSG | 5305 / 53 — Screws |
| Manufacturer | Hi-Shear Corporation |
| Status | ACTIVE |
| Surface Finish | 32.0 MICROINCHES THREADS |
| Surface Finish | 32.0 MICROINCHES GRIP |
| Surface Finish | 63.0 MICROINCHES BEARING SURFACE OF HEAD |
| Fastener Length | 1.991 INCHES MINIMUM AND 2.021 INCHES MAXIMUM IN |
| Surface Treatment Document and Classification | BAC 5861,CAGE81205 MFR REF SINGLE TREATMENT RESPONSE OVERALL |
| Thread Length | 0.694 INCHES NOMINAL IN |
| Material Document and Classification | AMS 4928 ASSN STD SINGLE MATERIAL RESPONSE OR AMS 4967 ASSN STD SINGLE MATERIAL RESPONSE OVERALL |
| Nominal Thread Diameter | 0.438 INCHES IN |
| Features Provided | CETYL ALCOHOL LUBRICANT |
| Head Style | FLAT COUNTERSUNK |
| Thread Direction | RIGHT-HAND |
| Grip Length | 1.302 INCHES MINIMUM AND 1.322 INCHES MAXIMUM IN |
| Grip Diameter | 0.4360 INCHES MINIMUM AND 0.4370 INCHES MAXIMUM IN |
| Surface Treatment | PHOSPHATE OVERALL |
| Internal Drive Style | HIGH-TORQUE |
| Countersink Angle | 99.0 DEGREES MINIMUM AND 101.0 DEGREES MAXIMUM |
| Thread Class | 3A A |
| Thread Quantity Per Inch | 20 |
| Material | TITANIUM ALLOY UNS R56400 OVERALL |
| Thread Series Designator | UNIFIED NATIONAL JOINT FINE (UNJF) |
| Head Diameter | 0.829 INCHES MINIMUM AND 0.892 INCHES MAXIMUM IN |
| Acquisition Status | ACTIVE |
| DEMIL Code | DEMIL A — No Demilitarization Required |
| Hazard | No hazard code in the DLA record (HMIC N) |
| Criticality Code | X |
| Part Number | Manufacturer |
|---|---|
| BACB30MS7R21 | Hi-Shear Corporation (USA) |
| BACB30MS7R21 | Howmet Global Fastening Systems Inc (USA) |
| BACB30MS7R21 | Lisi Aerospace Canada Corp Div Hi Shear Holdings Inc (CAN) |
| BACB30MS7R21 | Sps Technologies, Llc Dba PB Fasteners (USA) |
| Reference | Meaning |
|---|---|
| BACB30MS7R21 | 5/9 Secondary reference U.S. Government activity |
| BACB30MS7R21 | 5/9 Secondary reference Sps Technologies Inc |
| BACB30MS7R21 | C/1 Advisory reference — outside the item-of-supply concept Huck International, Inc |
| BACB30MS7R21 | 5/9 Secondary reference U.S. Government activity |
| BACB30MS7R21 | 5/2 Secondary reference U.S. Government activity |
| BACB30MS7R21 | 3/2 Design control — primary reference U.S. Government activity |
NSN 5305-01-337-0357 is a Screw,close Tolerance, manufactured by Hi-Shear Corporation, classified under FSC 5305, Screws. Status: active.
NSN 5305-01-337-0357 has 4 manufacturer part numbers on file: BACB30MS7R21 (Hi-Shear Corporation), BACB30MS7R21 (Howmet Global Fastening Systems Inc), BACB30MS7R21 (Lisi Aerospace Canada Corp Div Hi Shear Holdings Inc), BACB30MS7R21 (Sps Technologies, Llc Dba PB Fasteners).
Key specifications for BACB30MS7R21: Surface Finish: 32.0 MICROINCHES THREADS; Surface Finish: 32.0 MICROINCHES GRIP; Surface Finish: 63.0 MICROINCHES BEARING SURFACE OF HEAD; Fastener Length: 1.991 INCHES MINIMUM AND 2.021 INCHES MAXIMUM IN. 21 specifications are documented in the U.S. Government catalog.
No hazard code in the DLA record (HMIC N). Hazard information on this page is shown exactly as it appears in the DLA record.
U.S. Government catalog: edition PUBLOGDVD v12.0.0 (OCT 2026), edition date 2026-10-01, retrieved 2026-10-16.
U.S. Government catalog: edition PUBLOGDVD v12.0.0 (OCT 2026), edition date 2026-10-01, retrieved 2026-10-18.