Hex Head & Heavy Hex Bolts Supplier

Additional Specification

 

CAP SCREW THREAD INCH & METRIC

Inch Size Coarse(UNC) Fine(UNF)Decimal EquivalentClosest Metric SizeDecimal Conversion
1/4-20 .250 M6 X 1.0 .236"
1/4-28 .250 M6 X .075 .236
5/16-18 .3125 M8 X 1.25 .315
5/16-24 .3125 M8 X 1.0 .315
3/8-16 .375 M10 X 1.5 .394
3/8-24 .375 M10 X 1.25 .394
7/16-14 .4375    
7/16-20 .4375    
1/2-13 .500 M12 X 1.75 .472
1/2-20 .500 M12 X 1.25 .472
9/16-12 .5625 M14 X 2.0 .551
9/16-18 .5625 M14 X 1.5 .551
5/8-11 .625 M16 X 2.0 .630
5/8-18 .625 M16 X 1.5 .630
3/4-10 .750 M20 X 2.5 .787
3/4-16 .750 M20 X 1.5 .787
7/8-9 .875 M22 X 2.5 .866
7/8-14 .875 M22 X 1.5 .866
1-8 1.00 M24 X 3.0 .945
1-12 1.00 M24 X 2.0 .945
1-14 1.00    
1 1/8-7 1.125    
1 1/8-12 1.125    
1 1/4-7 1.25 M30 X3.5 1.181
1 1/4-12 1.25 M30 X 2.0 1.181

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STANDARD THREAD LENGTH FOR HEX HEAD CAP SCREWS

INCH FASTENERS

DiaLengths Threaded to the HeadLengths with Partial ThreadsMin. & Max Thread Lengths
 Lengths Up ToLengthsMin.-Max.
1/4 1 1/8 1-1/4 to 6 3/4 - 1.0
5/16 1 1/4 1-5/16 to 6 7/8 - 1.153
3/8 1 3/8 1-1/2 to 6 1 - 1.312
7/16 1 5/8 1-3/4 to 6 1 1/8 - 1.482
1/2 1 3/4 1-7/8 to 6 1 1/4 - 1.635
9/16 2 2-1/8 to 6 1 3/8 - 1.792
5/8 2 1/8 2-1/4 to 6 1 1/2 - 1.955
3/4 2 1/2 2-5/8 to 6 1 3/4 - 2.250
7/8 2 3/4 2-7/8 to 6 2 - 2.556
1 3 3-1/8 to 6 2 1/4 - 2.875
1 1/8 3 1/2 3-5/8 to 6 2 1/8 - 3.214
1 1/4 3 3/4 3-7/8 to 6 2 3/4 - 3.464
1 3/8 4 1/4 4-5/16 to 6 3 - 3.833
1 1/2 4 1/2 4-5/8 to 6 3 1/4 - 4.083
1 3/4 5 1/2 5-1/4 to 6 3 3/4 - 4.75
2 5 3/4 5-7/8 to 6 4 1/4 - 5.361
2 1/4 6 1/2 6-5/8 to 12 5 - 5.861
2 1/2 7 1/8 7-1/8 to 12 5 1/2 - 6.5

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INCH SIZE BOLT HEAD/WRENCH SIZE

Bolt DiameterHex Bolt Lag Bolt Square BoltHeavy Hex Bolts
#6 1/4  
#8 1/4  
#10 5/16  
#12 5/16  
1/4 7/16 or 3/8  
5/16 1/2  
3/8 9/16  
7/16 5/8  
1/2 3/4 7/8
9/16 13/16  
5/8 15/16 1 /16
3/4 1 1/8 1 1/4
7/8 1 5/16 1 7/16
1 1 1/2 1 5/8
1 1/8 1 11/16 1 3/4
1 1/4 1 7/8 2

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US Tap and Drill Bit Size

TapDrill Bit Size (Optional Letter/ Number)
0-80 3/64
1-64 53
2-56 50
3-48 47
4-40 3/32
5-40 38
6-32 7/64 (35)
8-32 29
10-24 5/32 (25)
10-32 5/32 (21)
12-24 11/64 (16)
1/4-20 13/64 (7)
1/4-28 7/32 (3)
5/16-18 17/64 (F)
5-16-24 I
3/8-16 5/16
3/8-24 21/64 (Q)
7/16-14 23/64 (U)
7/16-20 25/64
1/2-13 27/64
1/2-20 29/64
9/16-12 31/64
9/16-18 33/64
5/8-11 17/32
5/8-18 37/64
3/4-10 21/32
3/4-16 11/16

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INCH CAP SCREW STRENGTH

Inch GradeTensile Strength (Min)Yield Strength, min, (psi)Full Size Proofload, (psi)MaterialTreatment
Grade 2       Carbon Steel None
1/4 thru 3/4 74,000 57,000 55,000    
>3/4 thru 1 1/2 60,000 36,000 33,000    
Grade 5       Carbon Steel Quenched & Tempered
1/4 thru 1 120,000 92,000 85,000    
>1 thru 1 1/2 105,000 81,000 74,000    
Grade 8       Alloy Steel Quenched & Tempered
1/4 thru 1 1/2 150,000 130,000 120,000    

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Suggested Torque Values & Clamp Loads

Torque Values for Grades 2, 5, 8, and 9 Bolts - Coarse Thread

  SAE Gr. 2 SAE Gr. 5 SAE Gr. 8 Grade 9 
Nominal Size & tpiTensile Stress Area
(sq in)
Clamp Load
(lb)
Tightening Torque
(in-oz)
Clamp Load
(lb)
Tightening Torque
(in-oz)
Clamp Load
(lb)
Tightening Torque
(in-oz)
Clamp Load
(lb)
Tightening Torque
(in-oz)
1/4-20 0.0318 859 37
(in-lbs)
2029 86
(in-lbs)
2864 122
(in-lbs)
3357 143
(in-lbs)
5/16-18 0.0524 1416 75 3342 178 4719 251 5531 294
3/8-16 0.0775 2092 11 (ft-lbs) 4940 26 (ft-lbs) 6974 37 (ft-lbs) 8174 43 (ft-lbs)
7/16-14 0.14063 2870 18 6777 42 9568 59 11214 70
1/2-13 0.1419 3831 27 9046 64 12771 90 14969 106
9/16-12 0.1819 4912 39 11599 92 16375 130 19193 153
5/8-11 0.226 6102 54 14408 128 20340 180 23840 211
3/4-10 0.3345 9030 96 21322 227 30101 320 35281 375
7/8-9 0.4617 12467 155 29436 365 41556 515 48707 604
1-8 0.6057 16355 232 38616 547 54517 772 63899 905
1 1/4-7 0.9691 26166 463 53786 952 87220 1545 102229 1810
1 1/2-6 1.4053 37942 806 77991 1657 126473 2688 148237 3150

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Torque Values for Grades 2, 5, 8, and 9 Bolts - Fine Thread

  SAE Gr. 2 SAE Gr. 5 SAE Gr. 8 Grade 9 
Nominal Size & tpiTensile Stress Area
(sq in)
Clamp Load
(lb)
Tightening Torque
(in-oz)
Clamp Load
(lb)
Tightening Torque
(in-oz)
Clamp Load
(lb)
Tightening Torque
(in-oz)
Clamp Load
(lb)
Tightening Torque
(in-oz)
1/4-28 0.0364 982 42
(in-lbs)
2319 99
(in-lbs)
3274 139
(in-lbs)
3837 163
(in-lbs)
5/16-24 0.0581 1568 83 3702 197 5226 278 6125 325
3/8-24 0.0878 2371 13 (ft-lbs) 5599 30 (ft-lbs) 7905 42 (ft-lbs) 9265 49 (ft-lbs)
7/16-20 0.1187 3205 20 7568 47 10684 66 12523 78
1/2-20 0.16 4319 31 10197 72 14396 102 16873 120
9/16-18 0.203 5480 44 12940 103 18268 146 21412 171
5/8-18 0.256 6911 61 16317 144 23036 204 27000 239
3/4-16 0.373 10070 107 23776 253 33566 357 39343 418
7/8-14 0.5095 13756 171 32479 403 45853 568 53743 666
1-14 0.6799 18357 260 43343 614 61190 867 71720 1016
1 1/4-12 1.0729 28970 513 59548 1055 96565 1710 113182 2004
1 1/2-12 1.581 37942 907 87747 1865 142292 3024 166778 3544

 

All material in these charts are theoretical only. Use by anyone in an actual application is voluntary.

Torque Valuses are calculated from the formula - T = KDF, where

K = 0.17 for zinc plated, dry conditions
D = Nominal Diameter
F = Clamp Load

Clamp load calculated as 75% of the proof load when specified by the standard.

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bulk - you buy only the fasteners you need!

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