PROCUREMENT SPECIFICATION: MIL-B-８８３１
TITLE: BOLT,STEEL,EXTERNAL WRENCHING 180,000PSI FTU, 450°F, 12 POINT
CLASSIFICATION: STANDARD PART MS 21250
| Dash No. | Thread MIL-S-8879 |
A Diam |
B Diam |
Nom Size W |
D Diam |
E Diam |
H | J +.010 -.030 |
M | N Diam ±.005 |
P Max |
Q | R | S Max |
T Min |
U ±.016 |
| 02 | .1640- UNJC-3A |
.300 .290 |
.1635 .1625 |
0.2188 | .219 .204 |
0.076 | 0.25 | 0.10 | .062 | .037 | – | 0.05 | .041 .031 |
– | 0.385 | .031 |
| 03 | .1900-32 UNJF-3A |
.350 .340 |
.1895 .1885 |
0.25 | .250 .235 |
0.092 | 0.265 | 0.125 | 0.055 | 0.42 | ||||||
| 04 | .2500-28 UNJF-3A |
.438 .428 | .2495 .2485 | 0.3125 | .312 .297 | 0.135 | 0.30 | 0.18 | 0.069 | 0.492 | ||||||
| 05 | .3125-24 UNJF-3A |
.531 .521 | .3120 .3110 | 0.375 | .375 .360 | 0.162 | 0.348 | 0.215 | .070 | .055 | 0.082 | 0.579 | .047 | |||
| 06 | .3750-24 UNJF-3A |
.649 .639 | .3745 .3735 | 0.4375 | .437 .422 | 0.197 | 0.388 | 0.26 | 0.091 | .057 .047 | 0.625 | |||||
| 07 | 4375-20 UNJF-3A |
.750 .740 |
.4370 .4360 |
0.50 | .500 .485 |
0.228 | 0.435 | 0.32 | 0.099 | 0.721 | ||||||
| 08 | .5000-20 UNJF-3A |
.828 .818 | .4995 .4985 | 0.5625 | .562 .547 | 0.254 | 0.504 | 0.38 | .094 | 0.123 | 0.768 | |||||
| 09 | .5625-18 UNJF-3A |
.938 .928 |
.5615 .5605 |
0.625 | .625 .610 |
0.287 | 0.557 | 0.44 | 0.133 | 0.825 | .062 | |||||
| 10 | .6250-18 UNJF-3A |
1.050 1.040 |
.6240 .6230 |
0.6875 | .687 .672 |
0.327 | 0.618 | 0.50 | 0.15 | 0.899 | ||||||
| 12 | .7500-16 UNJF-3A |
1.230 1.220 |
.7490 .7480 |
0.8125 | .812 .797 |
0.38 | 0.711 | 0.57 | .200 | 0.178 | .073 .063 |
.187 | 1.036 | |||
| 14 | .8750-14 UNJF-3A |
1.438 1.428 |
.8740 .8730 |
0.9375 | .937 .922 |
0.438 | 0.808 | 0.65 | .125 | .260 | 0.198 | 1.244 | .078 | |||
| 16 | 1.000-12 UNJF-3A |
1.625 1.615 |
.9990 .9980 |
1.0625 | 1.062 1.047 |
0.493 | 0.923 | 0.74 | 0.222 | .250 | 1.479 |
| GRIP | MS 21250, LENGTH: ±.015 DIAMETER DASH NUMBER |
||||||||||||
| DASH No. |
GRIP ±.010 |
2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 12 | 14 | 15 |
| 4 | .25 | 0.655 | 0.69 | 0.762 | 0.849 | 0.895 | 0.991 | 1.038 | |||||
| 6 | .375 | 0.78 | 0.815 | 0.887 | 0.974 | 1.02 | 1.116 | 1.163 | 1.247 | 1.294 | 1.431 | ||
| 8 | .50 | 0.905 | 0.94 | 1.012 | 1.099 | 1.145 | 1.241 | 1.288 | 1.372 | 1.419 | 1.556 | 1.764 | 1.999 |
| 10 | .625 | 1.03 | 1.065 | 1.137 | 1.224 | 1.27 | 1.366 | 1.413 | 1.497 | 1.544 | 1.681 | 1.889 | 2.124 |
| 12 | .75 | 1.155 | 1.19 | 1.262 | 1.349 | 1.395 | 1.491 | 1.538 | 1.622 | 1.669 | 1.806 | 2.014 | 2.249 |
| 14 | .875 | 1.28 | 1.315 | 1.387 | 1.474 | 1.52 | 1.616 | 1.663 | 1.747 | 1.794 | 1.931 | 2.139 | 2.374 |
| 16 | 1.00 | 1.405 | 1.44 | 1.512 | 1.599 | 1.645 | 1.741 | 1.788 | 1.872 | 1.919 | 2.056 | 2.264 | 2.499 |
| 18 | 1.125 | 1.53 | 1.565 | 1.637 | 1.724 | 1.77 | 1.866 | 1.913 | 1.997 | 2.044 | 2.181 | 2.389 | 2.624 |
| 20 | 1.25 | 1.655 | 1.69 | 1.762 | 1.849 | 1.895 | 1.991 | 2.038 | 2.122 | 2.169 | 2.306 | 2.514 | 2.749 |
| 22 | 1.375 | 1.78 | 1.815 | 1.887 | 1.974 | 2.02 | 2.116 | 2.163 | 2.247 | 2.294 | 2.431 | 2.639 | 2.874 |
| 24 | 1.50 | 1.905 | 1.94 | 2.012 | 2.099 | 2.145 | 2.241 | 2.288 | 2.372 | 2.419 | 2.556 | 2.764 | 2.999 |
| 26 | 1.625 | 2.03 | 2.065 | 2.137 | 2.224 | 2.27 | 2.366 | 2.413 | 2.497 | 2.544 | 2.681 | 2.889 | 3.124 |
| 28 | 1.75 | 2.155 | 2.19 | 2.262 | 2.349 | 2.395 | 2.491 | 2.538 | 2.622 | 2.669 | 2.806 | 3.014 | 3.249 |
| 30 | 1.875 | 2.28 | 2.315 | 2.387 | 2.474 | 2.52 | 2.616 | 2.663 | 2.747 | 2.794 | 2.931 | 3.139 | 3.374 |
| 32 | 2.00 | 2.405 | 2.44 | 2.512 | 2.599 | 2.645 | 2.741 | 2.788 | 2.872 | 2.919 | 3.056 | 3.264 | 3.499 |
| 34 | 2.125 | 2.53 | 2.565 | 2.637 | 2.724 | 2.77 | 2.866 | 2.913 | 2.997 | 3.044 | 3.181 | 3.389 | 3.624 |
| 35 | 2.188 | 2.833 | |||||||||||
| 36 | 2.25 | 2.655 | 2.69 | 2.762 | 2.849 | 2.895 | 2.991 | 3.038 | 3.122 | 3.169 | 3.306 | 3.514 | 3.749 |
| 38 | 2.375 | 2.78 | 2.815 | 2.887 | 2.974 | 3.02 | 3.116 | 3.163 | 3.247 | 3.294 | 3.431 | 3.639 | 3.874 |
| 39 | 2.438 | 3.225 | |||||||||||
| 40 | 2.50 | 2.905 | 2.94 | 3.012 | 3.099 | 3.145 | 3.241 | 3.288 | 3.372 | 3.419 | 3.556 | 3.764 | 3.999 |
| 42 | 2.625 | 3.03 | 3.065 | 3.137 | 3.224 | 3.27 | 3.366 | 3.413 | 3.497 | 3.544 | 3.681 | 3.889 | 4.124 |
| 44 | 2.75 | 3.155 | 3.19 | 3.262 | 3.349 | 3.395 | 3.491 | 3.538 | 3.622 | 3.669 | 3.806 | 4.014 | 4.249 |
| 46 | 2.875 | 3.28 | 3.315 | 3.387 | 3.474 | 3.52 | 3.616 | 3.663 | 3.747 | 3.794 | 3.931 | 4.139 | 4.374 |
| 48 | 3.00 | 3.405 | 3.44 | 3.512 | 3.599 | 3.645 | 3.741 | 3.788 | 3.872 | 3.919 | 4.056 | 4.264 | 4.499 |
| 50 | 3.125 | 3.53 | 3.565 | 3.637 | 3.724 | 3.77 | 3.866 | 3.913 | 3.997 | 4.044 | 4.181 | 4.389 | 4.624 |
| 52 | 3.25 | 3.655 | 3.69 | 3.762 | 3.849 | 3.895 | 3.991 | 4.038 | 4.122 | 4.169 | 4.306 | 4.514 | 4.749 |
| 54 | 3.375 | 3.78 | 3.815 | 3.887 | 3.974 | 4.02 | 4.116 | 4.163 | 4.247 | 4.294 | 4.431 | 4.639 | 4.874 |
| 56 | 3.50 | 3.905 | 3.94 | 4.012 | 4.099 | 4.145 | 4.241 | 4.288 | 4.372 | 4.419 | 4.556 | 4.764 | 4.999 |
| 58 | 3.625 | 4.03 | 4.065 | 4.137 | 4.224 | 4.27 | 4.366 | 4.413 | 4.497 | 4.544 | 4.681 | 4.889 | 5.124 |
| 60 | 3.75 | 4.155 | 4.19 | 4.262 | 4.349 | 4.395 | 4.491 | 4.538 | 4.622 | 4.669 | 4.806 | 5.014 | 5.249 |
| 62 | 3.875 | 4.28 | 4.315 | 4.387 | 4.474 | 4.52 | 4.616 | 4.663 | 4.747 | 4.794 | 4.931 | 5.139 | 5.374 |
| 64 | 4.00 | 4.405 | 4.44 | 4.512 | 4.599 | 4.645 | 4.741 | 4.788 | 4.872 | 4.919 | 5.056 | 5.264 | 5.499 |
| 66 | 4.125 | 4.53 | 4.565 | 4.637 | 4.724 | 4.77 | 4.866 | 4.913 | 4.997 | 5.044 | 5.181 | 5.389 | 5.624 |
| 68 | 4.25 | 4.655 | 4.69 | 4.762 | 4.849 | 4.895 | 4.991 | 5.038 | 5.122 | 5.169 | 5.306 | 5.514 | 5.749 |
| 70 | 4.375 | 4.78 | 4.815 | 4.887 | 4.974 | 5.02 | 5.116 | 5.163 | 5.247 | 5.294 | 5.431 | 5.639 | 5.874 |
| 72 | 4.50 | 4.905 | 4.94 | 5.012 | 5.099 | 5.145 | 5.241 | 5.288 | 5.372 | 5.419 | 5.556 | 5.764 | 5.999 |
| 74 | 4.625 | 5.03 | 5.065 | 5.137 | 5.224 | 5.27 | 5.366 | 5.413 | 5.497 | 5.544 | 5.681 | 5.889 | 6.124 |
| 76 | 4.75 | 5.155 | 5.19 | 5.262 | 5.349 | 5.395 | 5.491 | 5.538 | 5.622 | 5.669 | 5.806 | 6.014 | 6.249 |
| 78 | 4.875 | 5.28 | 5.315 | 5.387 | 5.474 | 5.52 | 5.616 | 5.663 | 5.747 | 5.794 | 5.931 | 6.139 | 6.374 |
| 80 | 5.00 | 5.405 | 5.44 | 5.512 | 5.599 | 5.645 | 5.741 | 5.788 | 5.872 | 5.919 | 6.056 | 6.264 | 6.499 |
| 82 | 5.125 | 5.53 | 5.565 | 5.637 | 5.724 | 5.77 | 5.866 | 5.913 | 5.997 | 6.044 | 6.181 | 6.389 | 6.624 |
| 84 | 5.25 | 5.655 | 5.69 | 5.762 | 5.849 | 5.895 | 5.991 | 6.038 | 6.122 | 6.169 | 6.306 | 6.514 | 6.749 |
| 86 | 5.375 | 5.78 | 5.815 | 5.887 | 5.974 | 6.02 | 6.116 | 6.163 | 6.247 | 6.294 | 6.431 | 6.639 | 6.874 |
| 88 | 5.50 | 5.905 | 5.94 | 6.012 | 6.099 | 6.145 | 6.241 | 6.288 | 6.372 | 6.419 | 6.556 | 6.764 | 6.999 |
| 90 | 5.625 | 6.03 | 6.065 | 6.137 | 6.224 | 6.27 | 6.366 | 6.413 | 6.497 | 6.544 | 6.681 | 6.889 | 7.124 |
| 92 | 5.75 | 6.155 | 6.19 | 6.262 | 6.349 | 6.395 | 6.491 | 6.538 | 6.622 | 6.669 | 6.806 | 7.014 | 7.249 |
| 94 | 5.875 | 6.28 | 6.315 | 6.387 | 6.474 | 6.52 | 6.616 | 6.663 | 6.747 | 6.794 | 6.931 | 7.139 | 7.374 |
| 96 | 6.00 | 6.405 | 6.44 | 6.512 | 6.599 | 6.645 | 6.741 | 6.788 | 6.872 | 6.919 | 7.056 | 7.264 | 7.499 |
GRIP LENGTH OF BOLTS SHALL BE MEASURED FROM UNDERSIDE OF HEAD TO THE END OF FULL CYLINDRICAL PORTION OF THE SHANK.
DASH NO. INDICATED PREFERRED LENGTHS IN 0.125″ INCREMENTS. INTERMEDIATE OR LONGER LENGTHS IN 0.062″ INCREMENTS MAY BE
OBTAINED BY SPECIFIYING SIGNIFICANT DASH NUMBERS. LENGTH AND GRIP OF A BOLT WITH AN ODD DASH NUMBER WILL BE 0.061″
GREATER THAN SHOWN FOR THE BOLT WITH THE PRECEDING EVEN SECOND DASH NUMBER.