• Design Data for Threaded Fasteners

    Information about important design data for threaded fasteners is given in this article. Information is given on diameter / pitch combinations for metric threaded fasteners as per ISO; minimum ultimate tensile loads & proof loads for metric threaded fasteners as per ISO 898; nominal diameter, thread per inch (TPI) &  tensile stress area of imperial (inch) fasteners as per ANSI standard and tap drill sizes.

    Diameter / Pitch Combination for Metric Threaded Fasteners as per ISO

    Nominal Diameters Pitches
    1st Choice 2nd Choice 3rd Choice Coarse Fine
    M 1 - - 0.25 0.2
    - M 1.1 - 0.25 0.2
    M 1.2 - - 0.25 0.2
    - M 1.4 - 0.3 0.2
    M 1.6 - - 0.35 0.2
    - M 1.8 - 0.35 0.2
    M 2 - - 0.4 0.25
    - M 2.2 - 0.45 0.25
    M 2.5 - - 0.45 0.35
    M 3 - - 0.5 0.35
    - M 3.5 - 0.6 0.35
    M 4 - - 0.7 0.5
    - M 4.5 - 0.75 0.5
    M 5 - - 0.8 0.5
    - - M 5.5 - 0.5
    M 6 - - 1 0.75
    - - M 7 1 0.75
    M 8 - - 1.25 1, 0.75
    - - M 9 1.25 1, 0.75
    M 10 - - 1.5 1.25, 1, 0.75
    - - M 11 1.5 1, 0.75
    M 12 - - 1.75 1.5, 1.25, 1
    - M 14 - 2 1.5, 1.25, 1
    - - M 15 - 1.5, 1
    M 16 - - 2 1.5, 1
    - - M 17 - 1.5, 1
    - M 18 - 2.5 2, 1.5, 1
    M20 - - 2.5 2, 1.5, 1
    - M 22 - 2.5 2, 1.5, 1
    M 24 - - 3 2, 1.5, 1
    - - M25 - 2, 1.5, 1
    - - M 26 - 1.5
    - M27 - 3 2, 1.5, 1
    - - M 28 - 2, 1.5, 1
    M30 - - 3.5 3, 2, 1.5, 1
    - - M 32 - 2, 1.5
    - M 33 - 3.5 3, 2, 1.5
    - - M 35 - 1.5
    M 36 - - 4 3, 2, 1.5
    - - M 38 - 1.5
    - M 39 - 4 3, 2, 1.5
    - - M 40 - 3, 2, 1.5
    M 42 - - 4.5 4, 3, 2, 1.5
    - M 45 - 4.5 4, 3, 2, 1.5
    M 48 - - 5 4, 3, 2, 1.5
    - - M 50 - 3, 2, 1.5
    - M 52 - 5 4, 3, 2, 1.5
    - - M 55 - 4, 3, 2, 1.5
    M 56 - - 5.5 4, 3, 2, 1.5
    - - M 58 - 4, 3, 2, 1.5
    - M 60 - 5.5 4, 3, 2, 1.5
    - - M 62 - 4, 3, 2, 1.5
    M 64 - - 6 4, 3, 2, 1.5
    Nominal Diameters Pitches
    1st Choice 2nd Choice 3rd Choice Coarse Fine
    - - M 66 6 4, 3, 2, 1.5
    - M 68 - 6 4, 3, 2, 1.5
    - - M 70 6 6, 4, 3, 2, 1.5
    M 72 - - - 6, 4, 3, 2, 1.5
    - - M 75 - 4, 3, 2, 1.5
    - M 76 - - 6, 4, 3, 2, 1.5
    - - M 78 - 2
    M 80 - - - 6, 4, 3, 2, 1.5
    - - M 82 - 2
    - M 85 - - 6, 4, 3, 2
    M 90 - - - 6, 4, 3, 2
    - M 95 - - 6, 4, 3, 2
    M 100 - - - 6, 4, 3, 2
    - M 105 - - 6, 4, 3, 2
    M 110 - - - 6, 4, 3, 2
    - M 115 - - 6, 4, 3, 2
    - M 120 - - 6, 4, 3, 2
    M125 - - - 6, 4, 3, 2
    - M 130 - - 6, 4, 3, 2
    - - M 135 - 6, 4, 3, 2
    M 140 - - - 6, 4, 3, 2
    - - M 145 - 6, 4, 3, 2
    - M 150 - - 6, 4, 3, 2
    - - M 155 - 6, 4, 3
    M 160 - - - 6, 4, 3
    - - M 165 - 6, 4, 3
    - M 170 - - 6, 4, 3
    - - M 175 - 6, 4, 3
    M 180 - - - 6, 4, 3
    - - M 185 - 6, 4, 3
    - M 190 - - 6, 4, 3
    - - M 195 - 6, 4, 3
    M 200 - - - 6, 4, 3
    - - M 205 - 6, 4, 3
    - M 210 - - 6, 4, 3
    - - M 215 - 6, 4, 3
    M 220 - - - 6, 4, 3
    - - M 225 - 6, 4, 3
    - - M 230 - 6, 4, 3
    - - M 235 - 6, 4, 3
    - M 240 - - 6, 4, 3
    - - M 245 - 6, 4, 3
    M 250 - - - 6, 4, 3
    - - M 255 - 6, 4
    - M 260 - - 6, 4
    - - M 265 - 6, 4
    - - M 270 - 6, 4
    - - M 275 - 6, 4
    M 280 - - - 6, 4
    - - M 285 - 6, 4
    - - M 290 - 6, 4
    - - M 295 - 6, 4
    - M 300 - - 6, 4



    Minimum Ultimate Tensile Loads and Proof Loads for Coarse and Fine Threads as per ISO 898

    COARSE THREADS

    PROPERTY CLASS NOM. THRESD DIA. mm PITCH OF THE THREAD mm NOM. STRESS AREA mm2 PROPERTY CLASS
    5.6 5.8 6.8 8.8 9.8 10.9 12.9 5.6 5.8 6.8 8.8 9.8 10.9 12.9
    Minimum ultimate tensile load (As x Rm), N Proof Load (As x SP), N
    2510 2620 3020 4020 4530 5230 6140 3 0.5 5.03 1410 1910 2210 2920 3270 4180 4880
    3390 3530 4070 5420 6100 7050 8270 3.5 0.6 6.78 1900 2580 2980 3940 4410 5630 6580
    4390 4570 5270 7020 7900 9130 10700 4 0.7 8.78 2460 3340 3860 5100 5710 7290 8520
    7100 7380 8520 11350 12800 14800 17300 5 0.8 14.2 3980 5400 6250 8230 9230 11800 13800
    10000 10400 12100 16100 18100 20900 24500 6 1 20.1 5630 7640 8840 11600 13100 16700 19500
    14100 15000 17300 23100 26000 30100 35300 7 1 28.9 8090 11000 12700 16800 18800 24000 28000
    18300 19000 22000 29200 32900 38100 44600 8 1.25 36.6 10200 13900 16100 21200 23800 30400 35500
    29000 30200 34800 46400 52200 60300 70800 10 1.5 58.0 16200 22000 25500 33700 37700 48100 56300
    42200 43800 50600 67400 75900 87700 103000 12 1.75 84.3 23600 32000 37100 48900 54800 70000 18100
    57500 59800 69000 92000 104000 120000 140000 14 2 115 32200 43700 50600 66700 74800 95500 112000
    78500 81600 94000 125000 141000 163000 192000 16 2 157 44000 59700 69100 91000 102000 130000 152000
    96000 99800 115000 159000 - 200000 234000 18 2.5 192 53800 73000 84500 115000 - 159000 186000
    122000 127000 147000 203000 - 255000 299000 20 2.5 245 68600 93100 108000 147000 - 203000 238000
    152000 158000 182000 252000 - 315000 370000 22 2.5 303 84800 115000 133000 182000 - 252000 294000
    176000 184000 212000 293000 - 367000 431000 24 3 353 98800 134000 155000 212000 - 293000 342000
    230000 239000 275000 381000 - 477000 560000 27 3 459 128000 174000 202000 275000 - 381000 445000
    280000 292000 337000 466000 - 583000 684000 30 3.5 561 157000 213000 247000 337000 - 466000 544000
    347000 361000 416000 576000 - 722000 847000 33 3.5 694 194000 264000 305000 416000 - 570000 673000
    408000 425000 490000 678000 - 850000 997000 36 4 817 229000 310000 359000 490000 - 678000 792000
    488000 508000 586000 810000 - 1020000 1200000 39 4 976 273000 371000 429000 586000 - 810000 947000


    FINE THREADS

    PROPERTY CLASS NOM. THRESD DIA. mm PITCH OF THE THREAD mm NOM. STRESS AREA mm2 PROPERTY CLASS
    5.6 5.8 6.8 8.8 9.8 10.9 12.9 5.6 5.8 6.8 8.8 9.8 10.9 12.9
    Minimum ultimate tensile load (As x Rm), N Proof Load (As x SP), N
    19600 20400 23500 31360 353000 40800 47800 8 1 39.2 11000 14900 17200 22700 25500 32500 38000
    30600 31800 36700 49000 551000 63600 74700 10 1.25 61.2 17100 233000 26900 35500 39800 50800 59400
    46000 47900 553000 73700 829000 95800 112000 12 1.25 92.1 25800 35000 40500 53400 59900 76400 89300
    62500 65000 75000 100000 112000 130000 152000 14 1.5 125 35000 47500 55000 72500 81200 104000 121000
    83500 86800 100000 134000 150000 174000 204000 16 1.5 167 46800 63500 73500 96900 109000 139000 162000
    108000 112000 130000 179000 - 225000 264000 18 1.5 216 60500 82100 95000 130000 - 179000 210000
    136000 141000 163000 226000 - 283000 332000 20 1.5 272 76200 103000 120000 163000 - 226000 264000
    166000 173000 200000 276000 - 346000 406000 22 1.5 333 93200 126000 146000 200000 - 276000 323000
    192000 200000 230000 319000 - 399000 469000 24 2 384 108000 146000 169000 233000 - 319000 372000
    248000 258000 298000 412000 - 516000 605000 27 2 496 139000 188000 218000 298000 - 412000 481000
    310000 323000 373000 515000 - 646000 758000 30 2 621 174000 236000 273000 373000 - 515000 602000
    380000 396000 457000 632000 - 791000 928000 33 2 761 213000 289000 335000 457000 - 632000 738000
    432000 450000 519000 718000 - 900000 1050000 36 3 865 242000 329000 381000 519000 - 718000 838000
    515000 536000 618000 855000 - 1070000 1260000 39 3 1030 288000 391000 453000 618000 - 855000 999000



    Nominal Diameter, Threads per Inch (TPI) and Tensile Stress Areas of Imperial (Inch) Fasteners as per ANSI Standard

    Diameter (in.) Diameter (mm) Threads Per in. Square Inches
    Tensile Stress Area Per H-28 Nominal Shank
    UNRC UNRF UNRC UNRF
    #0 0.06 1.52 – 80 – 0.00180 0.002827
    #1 0.07 1.85 64 72 0.00263 0.00278 0.004185
    #2 0.09 2.18 56 64 0.00370 0.00394 0.005809
    #3 0.10 2.51 48 56 0.00487 0.00523 0.007698
    #4 0.11 2.84 40 48 0.00604 0.00661 0.009852
    #5 0.13 3.18 40 44 0.00796 0.00830 0.012272
    #6 0.14 3.51 32 40 0.00909 0.01015 0.014957
    #8 0.16 4.17 32 36 0.0140 0.01474 0.021124
    #10 0.19 4.83 24 32 0.0175 0.0200 0.028353
    1/4 0.25 6.35 20 28 0.0318 0.0364 0.049087
    5/16 0.31 7.94 18 24 0.0524 0.0580 0.076699
    3/8 0.38 9.53 16 24 0.0775 0.0878 0.11045
    7/16 0.44 11.11 14 20 0.1063 0.1187 0.15033
    1/2 0.50 12.70 13 20 0.1419 0.1599 0.19635
    9/16 0.56 14.29 12 18 0.182 0.203 0.25
    5/8 0.63 15.88 11 18 0.226 0.256 0.31
    3/4 0.75 19.05 10 16 0.334 0.373 0.44179
    7/8 0.88 22.23 9 14 0.462 0.509 0.60132
    1 1.00 25.40 8 12 0.606 0.663 0.79
    1-1/8 1.13 28.58 7 12 0.763 0.856 0.99402
    1-1/4 1.25 31.75 7 12 0.969 1.073 1.2272
    1-3/8 1.38 34.93 6 12 1.155 1.315 1.4849
    1-1/2 1.50 38.10 6 12 1.405 1.581 1.7671
    1-3/4 1.75 44.45 5 12 1.90 2.19 2.4053
    2 2.00 50.80 4-1/2 12 2.50 2.89 3.1416
    2-1/4 2.25 57.15 4-1/2 12 3.25 3.69 3.9761
    2-1/2 2.50 63.50 4 12 4.00 4.60 4.9088
    2-3/4 2.75 69.85 4 12 4.93 5.59 5.9396
    3 3.00 76.20 4 12 5.97 6.69 7.0686


    For tapping a hole to required specification, part need to be drilled based on thread specification. Following tables will be useful for selection of drill size.


    Tap Drill Size – Metric Threads

    METRIC COARSE SIZES
    TAP SIZE DRILL SIZE
    1mm x .25 .75mm
    1.1 x .25 .85
    1.2 x .25 .95
    1.4 x .3 1.1
    1.6 x .35 1.25
    1.7 x .35 1.3
    1.8 x .35 1.45
    2 x .4 1.6
    2.2 x .45 1.75
    2.5 x .45 2.05
    3 x .5 2.5
    3.5 x .6 2.9
    4 x .7 3.3
    4.5 x .75 3.7
    5 x .8 4.2
    6 x 1 5
    7 x 1 6
    8 x 1.25 6.8
    9 x 1.25 7.8
    10 x 1.5 8.5
    11 x 1.5 9.5
    12 x 1.75 10.2
    14 x 2 12
    16 x 2 14
    18 x 2.5 15.5
    20 x 2.5 17.5
    22 x 2.5 19.5
    24 x 3 21
    27 x 3 24
    30 x 3.5 26.5
    33 x 3.5 29.5
    36 x 4 32
    39 x 4 35
    METRIC FINE SIZES
    TAP SIZE DRILL SIZE
    4 mm x .35 3.6mm
    4 x .5 3.5
    5 x .5 4.5
    6 x .5 5.5
    6 x .75 5.25
    7 x .75 6.25
    8 x .5 7.5
    8 x .75 7.25
    8 x 1 7.0
    9 x 1 8
    10 x .75 9.25
    10 x 1 9
    10 x 1.25 8.8
    11 x 1 10
    12 x .75 11.25
    12 x 1 11
    12 x 1.5 10.5
    14 x 1 13
    14 x 1.25 12.8
    14 x 1.5 12.5
    16 x 1 15
    16 x 1.5 14.5
    18 x 1 17
    18 x 2 16
    20 x 1 19
    20 x 1.5 18.5
    20 x 2 18
    22 x 1 21
    22 x 1.5 20.5
    22 x 2 20
    24 x 1.5 22.5
    24 x 2 22
    26 x 1.5 24.5
    27 x 1.5 25.5
    27 x 2 25
    28 x 1.5 26.5
    30 x 1.5 28.5
    30 x 2 28
    33 x 2 31
    36 x 3 33
    39 x 3 36



    Tap Drill Size – Inch Threads

    INCH SIZES – UNC
    TAP SIZE DRILL SIZE
    #0-80 3/64"
    #1-64 #53
    #2-56 #51
    #3-48 5/64"
    #4-40 #43
    #5-40 #39
    #6-32 #36
    #8-32 #29
    #10-24 #25
    #12-24 #17
    1/4-20 #7
    5/16-18 F
    3/8-16 5/16
    7/16-14 U
    1/2-13 27/64
    9/16-12 31/64
    5/8-11 17/32
    3/4-10 21/32
    7/8-9 49/64
    1"-8 7/8
    1-1/8-7 63/64
    1-1/4-7 1-7/64
    1-1/2-6 1-11/32
    1-3/4-5 1-35/64
    2"-4-1/2 1-25/32
    INCH SIZES – UNF
    TAP SIZE DRILL SIZE
    #1-72 #53
    #2-64 #50
    #3-56 #46
    #4-48 #42
    #5-44 #37
    #6-40 #33
    #8-36 #29
    #10-32 #21
    #12-28 #15
    1/4-28 #3
    5/16-24 I
    3/8-24 Q
    7/16-20 W
    1/2-20 29/64
    9/16-18 33/64
    5/8-18 37/64
    3/4-16 11/16
    7/8-14 13/16
    1"-12 15/16
    1-1/8-12 1-3/64
    1-1/4-12 1-11/64
    1-1/2-12 1-27/64
    1-3/4-12 1-43/64
    2"-12 1-59/64

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