About Hex Head Screws and Bolts
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Mil. Spec. 18-8 Stainless Steel Hex Head Screws
Fully Threaded
Partially Threaded
Choose these screws for their adherence to strict military standards for material and construction. Made from 18-8 stainless steel, they have good chemical resistance and may be mildly magnetic. Dimensions meet Fed. Spec. FF-S-85 specifications. Length is measured from under the head.
Match the thread spacing of mating components. Coarse threads are the industry standard; choose these screws if you don’t know the threads per inch. Fine threads are closely spaced to prevent loosening from vibration.
For technical drawings and 3-D models, click on a part number.
Head | ||||||||||
|---|---|---|---|---|---|---|---|---|---|---|
| Lg. | Threading | Min. Thread Lg. | Thread Spacing  | Wd. | Ht. | Tensile Strength, psi | Specifications Met | Pkg. Qty. | Pkg. | |
1/4"-28 | ||||||||||
| 1/2" | Fully Threaded | __ | Fine | 7/16" | 5/32" | 70,000 | Fed. Spec. FF-S-85, MS35308-303 | 10 | 000000000 | 00000 |
| 9/16" | Fully Threaded | __ | Fine | 7/16" | 5/32" | 70,000 | Fed. Spec. FF-S-85, MS35308-304 | 10 | 000000000 | 0000 |
| 5/8" | Fully Threaded | __ | Fine | 7/16" | 5/32" | 70,000 | Fed. Spec. FF-S-85, MS35308-305 | 10 | 000000000 | 00000 |
| 3/4" | Fully Threaded | __ | Fine | 7/16" | 5/32" | 70,000 | Fed. Spec. FF-S-85, MS35308-306 | 10 | 000000000 | 0000 |
| 7/8" | Fully Threaded | __ | Fine | 7/16" | 5/32" | 70,000 | Fed. Spec. FF-S-85, MS35308-307 | 10 | 000000000 | 00000 |
| 1" | Partially Threaded | 3/4" | Fine | 7/16" | 5/32" | 70,000 | Fed. Spec. FF-S-85, MS35308-308 | 10 | 000000000 | 0000 |
| 1 1/8" | Partially Threaded | 3/4" | Fine | 7/16" | 5/32" | 70,000 | Fed. Spec. FF-S-85, MS35308-309 | 10 | 000000000 | 00000 |
| 1 1/4" | Partially Threaded | 3/4" | Fine | 7/16" | 5/32" | 70,000 | Fed. Spec. FF-S-85, MS35308-310 | 10 | 000000000 | 00000 |
| 1 3/8" | Partially Threaded | 3/4" | Fine | 7/16" | 5/32" | 70,000 | Fed. Spec. FF-S-85, MS35308-311 | 10 | 000000000 | 00000 |
| 1 1/2" | Partially Threaded | 3/4" | Fine | 7/16" | 5/32" | 70,000 | Fed. Spec. FF-S-85, MS35308-312 | 10 | 000000000 | 00000 |
| 1 3/4" | Partially Threaded | 3/4" | Fine | 7/16" | 5/32" | 70,000 | Fed. Spec. FF-S-85, MS35308-313 | 10 | 000000000 | 00000 |
| 2" | Partially Threaded | 3/4" | Fine | 7/16" | 5/32" | 70,000 | Fed. Spec. FF-S-85, MS35308-314 | 5 | 000000000 | 00000 |
| 2 1/4" | Partially Threaded | 3/4" | Fine | 7/16" | 5/32" | 70,000 | Fed. Spec. FF-S-85, MS35308-315 | 5 | 000000000 | 00000 |
| 2 1/2" | Partially Threaded | 3/4" | Fine | 7/16" | 5/32" | 70,000 | Fed. Spec. FF-S-85, MS35308-316 | 5 | 000000000 | 00000 |
| 3" | Partially Threaded | 3/4" | Fine | 7/16" | 5/32" | 70,000 | Fed. Spec. FF-S-85, MS35308-318 | 5 | 000000000 | 00000 |
5/16"-24 | ||||||||||
| 5/8" | Fully Threaded | __ | Fine | 1/2" | 13/64" | 70,000 | Fed. Spec. FF-S-85, MS35308-331 | 10 | 000000000 | 00000 |
| 3/4" | Fully Threaded | __ | Fine | 1/2" | 13/64" | 70,000 | Fed. Spec. FF-S-85, MS35308-332 | 5 | 000000000 | 0000 |
| 7/8" | Fully Threaded | __ | Fine | 1/2" | 13/64" | 70,000 | Fed. Spec. FF-S-85, MS35308-333 | 5 | 000000000 | 00000 |
| 1" | Partially Threaded | 7/8" | Fine | 1/2" | 13/64" | 70,000 | Fed. Spec. FF-S-85, MS35308-334 | 5 | 000000000 | 00000 |
| 1 1/8" | Partially Threaded | 7/8" | Fine | 1/2" | 13/64" | 70,000 | Fed. Spec. FF-S-85, MS35308-335 | 5 | 000000000 | 00000 |
| 1 1/4" | Partially Threaded | 7/8" | Fine | 1/2" | 13/64" | 70,000 | Fed. Spec. FF-S-85, MS35308-336 | 5 | 000000000 | 00000 |
| 1 3/8" | Partially Threaded | 7/8" | Fine | 1/2" | 13/64" | 70,000 | Fed. Spec. FF-S-85, MS35308-337 | 5 | 000000000 | 00000 |
| 1 1/2" | Partially Threaded | 7/8" | Fine | 1/2" | 13/64" | 70,000 | Fed. Spec. FF-S-85, MS35308-338 | 5 | 000000000 | 00000 |
| 1 3/4" | Partially Threaded | 7/8" | Fine | 1/2" | 13/64" | 70,000 | Fed. Spec. FF-S-85, MS35308-339 | 5 | 000000000 | 00000 |
| 2" | Partially Threaded | 7/8" | Fine | 1/2" | 13/64" | 70,000 | Fed. Spec. FF-S-85, MS35308-340 | 1 | 000000000 | 0000 |
| 2 1/4" | Partially Threaded | 7/8" | Fine | 1/2" | 13/64" | 70,000 | Fed. Spec. FF-S-85, MS35308-341 | 1 | 000000000 | 0000 |
| 2 1/2" | Partially Threaded | 7/8" | Fine | 1/2" | 13/64" | 70,000 | Fed. Spec. FF-S-85, MS35308-342 | 1 | 000000000 | 0000 |
| 2 3/4" | Partially Threaded | 7/8" | Fine | 1/2" | 13/64" | 70,000 | Fed. Spec. FF-S-85, MS35308-343 | 1 | 000000000 | 0000 |
3/8"-24 | ||||||||||
| 5/8" | Fully Threaded | __ | Fine | 9/16" | 15/64" | 70,000 | Fed. Spec. FF-S-85, MS35308-357 | 5 | 000000000 | 0000 |
| 3/4" | Fully Threaded | __ | Fine | 9/16" | 15/64" | 70,000 | Fed. Spec. FF-S-85, MS35308-358 | 5 | 000000000 | 00000 |
| 7/8" | Fully Threaded | __ | Fine | 9/16" | 15/64" | 70,000 | Fed. Spec. FF-S-85, MS35308-359 | 5 | 000000000 | 00000 |
| 1" | Fully Threaded | __ | Fine | 9/16" | 15/64" | 70,000 | Fed. Spec. FF-S-85, MS35308-360 | 5 | 000000000 | 00000 |
| 1 1/8" | Fully Threaded | __ | Fine | 9/16" | 15/64" | 70,000 | Fed. Spec. FF-S-85, MS35308-361 | 1 | 000000000 | 0000 |
| 1 1/4" | Partially Threaded | 1" | Fine | 9/16" | 15/64" | 70,000 | Fed. Spec. FF-S-85, MS35308-362 | 1 | 000000000 | 0000 |
| 1 3/8" | Partially Threaded | 1" | Fine | 9/16" | 15/64" | 70,000 | Fed. Spec. FF-S-85, MS35308-363 | 1 | 000000000 | 0000 |
| 1 1/2" | Partially Threaded | 1" | Fine | 9/16" | 15/64" | 70,000 | Fed. Spec. FF-S-85, MS35308-364 | 1 | 000000000 | 0000 |
| 1 3/4" | Partially Threaded | 1" | Fine | 9/16" | 15/64" | 70,000 | Fed. Spec. FF-S-85, MS35308-365 | 1 | 000000000 | 0000 |
| 2" | Partially Threaded | 1" | Fine | 9/16" | 15/64" | 70,000 | Fed. Spec. FF-S-85, MS35308-366 | 1 | 000000000 | 0000 |
| 2 1/4" | Partially Threaded | 1" | Fine | 9/16" | 15/64" | 70,000 | Fed. Spec. FF-S-85, MS35308-367 | 1 | 000000000 | 0000 |
| 2 1/2" | Partially Threaded | 1" | Fine | 9/16" | 15/64" | 70,000 | Fed. Spec. FF-S-85, MS35308-368 | 1 | 000000000 | 0000 |
| 3" | Partially Threaded | 1" | Fine | 9/16" | 15/64" | 70,000 | Fed. Spec. FF-S-85, MS35308-370 | 1 | 000000000 | 0000 |
1/2"-20 | ||||||||||
| 3/4" | Fully Threaded | __ | Fine | 3/4" | 5/16" | 70,000 | Fed. Spec. FF-S-85, MS35308-407 | 1 | 000000000 | 0000 |
| 1" | Fully Threaded | __ | Fine | 3/4" | 5/16" | 70,000 | Fed. Spec. FF-S-85, MS35308-409 | 1 | 000000000 | 0000 |
| 1 1/8" | Fully Threaded | __ | Fine | 3/4" | 5/16" | 70,000 | Fed. Spec. FF-S-85, MS35308-410 | 1 | 000000000 | 0000 |
| 1 1/4" | Fully Threaded | __ | Fine | 3/4" | 5/16" | 70,000 | Fed. Spec. FF-S-85, MS35308-411 | 1 | 000000000 | 0000 |
| 1 1/2" | Partially Threaded | 1 1/4" | Fine | 3/4" | 5/16" | 70,000 | Fed. Spec. FF-S-85, MS35308-413 | 1 | 000000000 | 0000 |
| 1 3/4" | Partially Threaded | 1 1/4" | Fine | 3/4" | 5/16" | 70,000 | Fed. Spec. FF-S-85, MS35308-414 | 1 | 000000000 | 0000 |
| 2" | Partially Threaded | 1 1/4" | Fine | 3/4" | 5/16" | 70,000 | Fed. Spec. FF-S-85, MS35308-415 | 1 | 000000000 | 0000 |
| 2 1/4" | Partially Threaded | 1 1/4" | Fine | 3/4" | 5/16" | 70,000 | Fed. Spec. FF-S-85, MS35308-416 | 1 | 000000000 | 00000 |
| 2 1/2" | Partially Threaded | 1 1/4" | Fine | 3/4" | 5/16" | 70,000 | Fed. Spec. FF-S-85, MS35308-417 | 1 | 000000000 | 00000 |
| 2 3/4" | Partially Threaded | 1 1/4" | Coarse | 3/4" | 5/16" | 70,000 | Fed. Spec. FF-S-85, MS35308-418 | 1 | 000000000 | 00000 |
| 3" | Partially Threaded | 1 1/4" | Coarse | 3/4" | 5/16" | 70,000 | Fed. Spec. FF-S-85, MS35308-419 | 1 | 000000000 | 00000 |