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"-20 | ||||||||||
| 1/2" | Fully Threaded | __ | Coarse | 7/16" | 5/32" | 70,000 | Fed. Spec. FF-S-85, MS35307-303 | 10 | 000000000 | 00000 |
| 9/16" | Fully Threaded | __ | Coarse | 7/16" | 5/32" | 70,000 | Fed. Spec. FF-S-85, MS35307-304 | 10 | 000000000 | 00000 |
| 5/8" | Fully Threaded | __ | Coarse | 7/16" | 5/32" | 70,000 | Fed. Spec. FF-S-85, MS35307-305 | 10 | 000000000 | 00000 |
| 3/4" | Fully Threaded | __ | Coarse | 7/16" | 5/32" | 70,000 | Fed. Spec. FF-S-85, MS35307-306 | 10 | 000000000 | 0000 |
| 7/8" | Partially Threaded | 3/4" | Coarse | 7/16" | 5/32" | 70,000 | Fed. Spec. FF-S-85, MS35307-307 | 10 | 000000000 | 0000 |
| 1" | Partially Threaded | 3/4" | Coarse | 7/16" | 5/32" | 70,000 | Fed. Spec. FF-S-85, MS35307-308 | 10 | 000000000 | 00000 |
| 1 1/8" | Partially Threaded | 3/4" | Coarse | 7/16" | 5/32" | 70,000 | Fed. Spec. FF-S-85, MS35307-309 | 10 | 000000000 | 00000 |
| 1 1/4" | Partially Threaded | 3/4" | Coarse | 7/16" | 5/32" | 70,000 | Fed. Spec. FF-S-85, MS35307-310 | 10 | 000000000 | 00000 |
| 1 3/8" | Partially Threaded | 3/4" | Coarse | 7/16" | 5/32" | 70,000 | Fed. Spec. FF-S-85, MS35307-311 | 10 | 000000000 | 00000 |
| 1 1/2" | Partially Threaded | 3/4" | Coarse | 7/16" | 5/32" | 70,000 | Fed. Spec. FF-S-85, MS35307-312 | 5 | 000000000 | 0000 |
| 1 3/4" | Partially Threaded | 3/4" | Coarse | 7/16" | 5/32" | 70,000 | Fed. Spec. FF-S-85, MS35307-313 | 5 | 000000000 | 00000 |
| 2" | Partially Threaded | 3/4" | Coarse | 7/16" | 5/32" | 70,000 | Fed. Spec. FF-S-85, MS35307-314 | 5 | 000000000 | 00000 |
| 2 1/4" | Partially Threaded | 3/4" | Coarse | 7/16" | 5/32" | 70,000 | Fed. Spec. FF-S-85, MS35307-315 | 5 | 000000000 | 00000 |
| 2 1/2" | Partially Threaded | 3/4" | Coarse | 7/16" | 5/32" | 70,000 | Fed. Spec. FF-S-85, MS35307-316 | 5 | 000000000 | 00000 |
| 2 3/4" | Partially Threaded | 3/4" | Coarse | 7/16" | 5/32" | 70,000 | Fed. Spec. FF-S-85, MS35307-317 | 5 | 000000000 | 00000 |
| 3" | Partially Threaded | 3/4" | Coarse | 7/16" | 5/32" | 70,000 | Fed. Spec. FF-S-85, MS35307-318 | 5 | 000000000 | 00000 |
| 3 1/2" | Partially Threaded | 3/4" | Coarse | 7/16" | 5/32" | 70,000 | Fed. Spec. FF-S-85, MS35307-320 | 5 | 000000000 | 00000 |
| 3 3/4" | Partially Threaded | 3/4" | Coarse | 7/16" | 5/32" | 70,000 | Fed. Spec. FF-S-85, MS35307-321 | 1 | 000000000 | 0000 |
| 4" | Partially Threaded | 3/4" | Coarse | 7/16" | 5/32" | 70,000 | Fed. Spec. FF-S-85, MS35307-322 | 1 | 000000000 | 0000 |
5/16"-18 | ||||||||||
| 1/2" | Fully Threaded | __ | Coarse | 1/2" | 13/64" | 70,000 | Fed. Spec. FF-S-85, MS35307-329 | 10 | 000000000 | 00000 |
| 5/8" | Fully Threaded | __ | Coarse | 1/2" | 13/64" | 70,000 | Fed. Spec. FF-S-85, MS35307-331 | 10 | 000000000 | 00000 |
| 3/4" | Fully Threaded | __ | Coarse | 1/2" | 13/64" | 70,000 | Fed. Spec. FF-S-85, MS35307-332 | 10 | 000000000 | 00000 |
| 7/8" | Fully Threaded | __ | Coarse | 1/2" | 13/64" | 70,000 | Fed. Spec. FF-S-85, MS35307-333 | 5 | 000000000 | 00000 |
| 1" | Partially Threaded | 7/8" | Coarse | 1/2" | 13/64" | 70,000 | Fed. Spec. FF-S-85, MS35307-334 | 5 | 000000000 | 0000 |
| 1 1/8" | Partially Threaded | 7/8" | Coarse | 1/2" | 13/64" | 70,000 | Fed. Spec. FF-S-85, MS35307-335 | 5 | 000000000 | 00000 |
| 1 1/4" | Partially Threaded | 7/8" | Coarse | 1/2" | 13/64" | 70,000 | Fed. Spec. FF-S-85, MS35307-336 | 5 | 000000000 | 0000 |
| 1 3/8" | Partially Threaded | 7/8" | Coarse | 1/2" | 13/64" | 70,000 | Fed. Spec. FF-S-85, MS35307-337 | 5 | 000000000 | 00000 |
| 1 1/2" | Partially Threaded | 7/8" | Coarse | 1/2" | 13/64" | 70,000 | Fed. Spec. FF-S-85, MS35307-338 | 5 | 000000000 | 00000 |
| 1 3/4" | Partially Threaded | 7/8" | Coarse | 1/2" | 13/64" | 70,000 | Fed. Spec. FF-S-85, MS35307-339 | 5 | 000000000 | 00000 |
| 2" | Partially Threaded | 7/8" | Coarse | 1/2" | 13/64" | 70,000 | Fed. Spec. FF-S-85, MS35307-340 | 1 | 000000000 | 0000 |
| 2 1/4" | Partially Threaded | 7/8" | Coarse | 1/2" | 13/64" | 70,000 | Fed. Spec. FF-S-85, MS35307-341 | 1 | 000000000 | 0000 |
| 2 1/2" | Partially Threaded | 7/8" | Coarse | 1/2" | 13/64" | 70,000 | Fed. Spec. FF-S-85, MS35307-342 | 1 | 000000000 | 0000 |
| 2 3/4" | Partially Threaded | 7/8" | Coarse | 1/2" | 13/64" | 70,000 | Fed. Spec. FF-S-85, MS35307-343 | 1 | 000000000 | 0000 |
| 3" | Partially Threaded | 7/8" | Coarse | 1/2" | 13/64" | 70,000 | Fed. Spec. FF-S-85, MS35307-344 | 1 | 000000000 | 0000 |
| 3 1/4" | Partially Threaded | 7/8" | Fine | 1/2" | 13/64" | 70,000 | Fed. Spec. FF-S-85, MS35307-345 | 1 | 000000000 | 0000 |
| 3 1/2" | Partially Threaded | 7/8" | Coarse | 1/2" | 13/64" | 70,000 | Fed. Spec. FF-S-85, MS35307-346 | 1 | 000000000 | 0000 |
3/8"-16 | ||||||||||
| 1/2" | Fully Threaded | __ | Coarse | 9/16" | 15/64" | 70,000 | Fed. Spec. FF-S-85, MS35307-355 | 5 | 000000000 | 00000 |
| 5/8" | Fully Threaded | __ | Coarse | 9/16" | 15/64" | 70,000 | Fed. Spec. FF-S-85, MS35307-357 | 5 | 000000000 | 00000 |
| 3/4" | Fully Threaded | __ | Coarse | 9/16" | 15/64" | 70,000 | Fed. Spec. FF-S-85, MS35307-358 | 5 | 000000000 | 00000 |
| 7/8" | Fully Threaded | __ | Coarse | 9/16" | 15/64" | 70,000 | Fed. Spec. FF-S-85, MS35307-359 | 5 | 000000000 | 00000 |
| 1" | Fully Threaded | __ | Coarse | 9/16" | 15/64" | 70,000 | Fed. Spec. FF-S-85, MS35307-360 | 5 | 000000000 | 00000 |
| 1 1/8" | Fully Threaded | __ | Coarse | 9/16" | 15/64" | 70,000 | Fed. Spec. FF-S-85, MS35307-361 | 5 | 000000000 | 00000 |
| 1 1/4" | Partially Threaded | 1" | Coarse | 9/16" | 15/64" | 70,000 | Fed. Spec. FF-S-85, MS35307-362 | 1 | 000000000 | 0000 |
| 1 3/8" | Partially Threaded | 1" | Coarse | 9/16" | 15/64" | 70,000 | Fed. Spec. FF-S-85, MS35307-363 | 1 | 000000000 | 0000 |
| 1 1/2" | Partially Threaded | 1" | Coarse | 9/16" | 15/64" | 70,000 | Fed. Spec. FF-S-85, MS35307-364 | 1 | 000000000 | 0000 |
| 1 3/4" | Partially Threaded | 1" | Coarse | 9/16" | 15/64" | 70,000 | Fed. Spec. FF-S-85, MS35307-365 | 1 | 000000000 | 0000 |
| 2" | Partially Threaded | 1" | Coarse | 9/16" | 15/64" | 70,000 | Fed. Spec. FF-S-85, MS35307-366 | 1 | 000000000 | 0000 |
| 2 1/4" | Partially Threaded | 1" | Coarse | 9/16" | 15/64" | 70,000 | Fed. Spec. FF-S-85, MS35307-367 | 1 | 000000000 | 0000 |
| 2 1/2" | Partially Threaded | 1" | Coarse | 9/16" | 15/64" | 70,000 | Fed. Spec. FF-S-85, MS35307-368 | 1 | 000000000 | 0000 |
| 2 3/4" | Partially Threaded | 1" | Coarse | 9/16" | 15/64" | 70,000 | Fed. Spec. FF-S-85, MS35307-369 | 1 | 000000000 | 0000 |
| 3" | Partially Threaded | 1" | Coarse | 9/16" | 15/64" | 70,000 | Fed. Spec. FF-S-85, MS35307-370 | 1 | 000000000 | 0000 |
| 3 1/2" | Partially Threaded | 1" | Coarse | 9/16" | 15/64" | 70,000 | Fed. Spec. FF-S-85, MS35307-372 | 1 | 000000000 | 0000 |
| 3 3/4" | Partially Threaded | 1" | Coarse | 9/16" | 15/64" | 70,000 | Fed. Spec. FF-S-85, MS35307-373 | 1 | 000000000 | 0000 |
1/2"-13 | ||||||||||
| 3/4" | Fully Threaded | __ | Coarse | 3/4" | 5/16" | 70,000 | Fed. Spec. FF-S-85, MS35307-407 | 1 | 000000000 | 0000 |
| 1" | Fully Threaded | __ | Coarse | 3/4" | 5/16" | 70,000 | Fed. Spec. FF-S-85, MS35307-409 | 1 | 000000000 | 0000 |
| 1 1/8" | Fully Threaded | __ | Coarse | 3/4" | 5/16" | 70,000 | Fed. Spec. FF-S-85, MS35307-410 | 1 | 000000000 | 0000 |
| 1 1/4" | Fully Threaded | __ | Coarse | 3/4" | 5/16" | 70,000 | Fed. Spec. FF-S-85, MS35307-411 | 1 | 000000000 | 0000 |
| 1 3/8" | Fully Threaded | __ | Coarse | 3/4" | 5/16" | 70,000 | Fed. Spec. FF-S-85, MS35307-412 | 1 | 000000000 | 0000 |
| 1 1/2" | Partially Threaded | 1 1/4" | Coarse | 3/4" | 5/16" | 70,000 | Fed. Spec. FF-S-85, MS35307-413 | 1 | 000000000 | 0000 |
| 1 3/4" | Partially Threaded | 1 1/4" | Coarse | 3/4" | 5/16" | 70,000 | Fed. Spec. FF-S-85, MS35307-414 | 1 | 000000000 | 0000 |
| 2" | Partially Threaded | 1 1/4" | Coarse | 3/4" | 5/16" | 70,000 | Fed. Spec. FF-S-85, MS35307-415 | 1 | 000000000 | 0000 |
| 2 1/4" | Partially Threaded | 1 1/4" | Coarse | 3/4" | 5/16" | 70,000 | Fed. Spec. FF-S-85, MS35307-416 | 1 | 000000000 | 00000 |
| 2 1/2" | Partially Threaded | 1 1/4" | Coarse | 3/4" | 5/16" | 70,000 | Fed. Spec. FF-S-85, MS35307-417 | 1 | 000000000 | 0000 |
| 2 3/4" | Partially Threaded | 1 1/4" | Coarse | 3/4" | 5/16" | 70,000 | Fed. Spec. FF-S-85, MS35307-418 | 1 | 000000000 | 0000 |
| 3" | Partially Threaded | 1 1/4" | Coarse | 3/4" | 5/16" | 70,000 | Fed. Spec. FF-S-85, MS35307-419 | 1 | 000000000 | 0000 |
5/8"-11 | ||||||||||
| 1" | Fully Threaded | __ | Coarse | 15/16" | 25/64" | 70,000 | Fed. Spec. FF-S-85, MS35307-458 | 1 | 000000000 | 00000 |
| 1 1/4" | Fully Threaded | __ | Coarse | 15/16" | 25/64" | 70,000 | Fed. Spec. FF-S-85, MS35307-460 | 1 | 000000000 | 00000 |
| 1 1/2" | Fully Threaded | __ | Coarse | 15/16" | 25/64" | 70,000 | Fed. Spec. FF-S-85, MS35307-462 | 1 | 000000000 | 00000 |
| 1 3/4" | Partially Threaded | 1 1/2" | Coarse | 15/16" | 25/64" | 70,000 | Fed. Spec. FF-S-85, MS35307-463 | 1 | 000000000 | 00000 |
| 2" | Partially Threaded | 1 1/2" | Coarse | 15/16" | 25/64" | 70,000 | Fed. Spec. FF-S-85, MS35307-464 | 1 | 000000000 | 00000 |
| 2 1/4" | Partially Threaded | 1 1/2" | Coarse | 15/16" | 25/64" | 70,000 | Fed. Spec. FF-S-85, MS35307-465 | 1 | 000000000 | 00000 |
| 2 1/2" | Partially Threaded | 1 1/2" | Coarse | 15/16" | 25/64" | 70,000 | Fed. Spec. FF-S-85, MS35307-466 | 1 | 000000000 | 00000 |
| 2 3/4" | Partially Threaded | 1 1/2" | Coarse | 15/16" | 25/64" | 70,000 | Fed. Spec. FF-S-85, MS35307-467 | 1 | 000000000 | 00000 |
| 3" | Partially Threaded | 1 1/2" | Coarse | 15/16" | 25/64" | 70,000 | Fed. Spec. FF-S-85, MS35307-468 | 1 | 000000000 | 00000 |
| 3 1/2" | Partially Threaded | 1 1/2" | Coarse | 15/16" | 25/64" | 70,000 | Fed. Spec. FF-S-85, MS35307-470 | 1 | 000000000 | 00000 |
| 4" | Partially Threaded | 1 1/2" | Coarse | 15/16" | 25/64" | 70,000 | Fed. Spec. FF-S-85, MS35307-472 | 1 | 000000000 | 00000 |
3/4"-10 | ||||||||||
| 1 1/2" | Fully Threaded | __ | Coarse | 1 1/8" | 15/32" | 70,000 | Fed. Spec. FF-S-85, MS35307-485 | 1 | 000000000 | 00000 |
| 2" | Fully Threaded | __ | Coarse | 1 1/8" | 15/32" | 70,000 | Fed. Spec. FF-S-85, MS35307-487 | 1 | 000000000 | 00000 |
| 2 1/4" | Partially Threaded | 1 3/4" | Coarse | 1 1/8" | 15/32" | 70,000 | Fed. Spec. FF-S-85, MS35307-488 | 1 | 000000000 | 00000 |
| 2 1/2" | Partially Threaded | 1 3/4" | Coarse | 1 1/8" | 15/32" | 70,000 | Fed. Spec. FF-S-85, MS35307-489 | 1 | 000000000 | 00000 |
| 3" | Partially Threaded | 1 3/4" | Coarse | 1 1/8" | 15/32" | 70,000 | Fed. Spec. FF-S-85, MS35307-491 | 1 | 000000000 | 00000 |