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Full Thread Vs Half Thread Bolts

Full Thread Vs Half Thread Bolts



Calculate Thread Length of Half Thread Bolt as per ASME B18 2.1


What is Full Thread Bolt ?


A full thread bolt is a type of bolt where have no thread-free portion, meaning that the threads run from under the head to the tip.


What is Half Thread Bolt ?


A half thread bolt has threads covering only part of its length, with the remaining portion being smooth. In bolts, this smooth portion is called the shank.


Difference Between Full Thread Vs Half Thread Bolts


Difference Between Full Thread Vs Half Thread Bolts

Aspects Full Thread Half Thread
Coverage of Thread Fully Thread from end to end Half threaded, smooth section remains
Tensile Strength High Low
Strength for Grip High Moderate
Applications Secure pipeline connections Structural applications for shear loads

Calculate Thread Length for Half Head Bolts


Available Sizes in (MM)
≥M6x25 (M6x25x18s)
≥M8x30 (M8x30x22s)
≥M10x30 (M10x30x26s)
≥M12x35 (M12x35x30s)
≥M14x40 (M14x40x34s)
≥M16x45 (M16x45x38s)
≥M18x50 (M18x50x42s)
≥M20x50 (M20x50x46s)
≥M22x60 (M22x60x50s)
≥M24x65 (M24x65x54s)

Applications of Full-Threaded Hex Bolts


Structural Steel Applications

Structural Steel Applications

Construction projects

Construction projects

Automotive and Transportation Industries

Automotive and Transportation Industries


Applications of Half-Threaded Hex Bolts


Furniture Manufacturing

Furniture Manufacturing

Electrical Industries

Electrical Industries

Electronics Industries

Electronics Industries


Discover Advantages of Half Thread and Full Thread Bolt


Threads Types of Full Thread Cap Head Screws


  • Unified National Coarse
  • Unified National Extra Fine
  • Unified National Fine
  • UNJC and UNJF
  • UNR and UNK
  • Constant-Pitch

Fully Threaded Hex Bolts Dimensions


Fully Threaded Hex Bolts Dimensions

Nominal Diameter Head Height(H) Width Across Corners (G) Width Across Flats (F)
Basic Min   Max  Min  Max Basic Min Max
1/2 5/16 .302 .323 .840 .866 3/4 .736 .750
1/4 5/32 .150 .163 .488 .505 7/16 .428 .438
1 43/64 .591 .700 1.653 1.732 1-1/2 1.450 1.500
1-1/4 27/32 .749 .876 2.066 2.165 1-7/8 1.812 1.875
3/4 15/32 .455 .483 1.254 1.299 1-1/8 1.100 1.125
3/8 15/64 .226 .243 .628 .650 9/16 .551 .562
5/8 25/64 .378 .403 1.051 1.083 15/16 .922 .938
5/16 13/64 .195 .211 .557 .577 1/2 .489 .500
7/8 37/64 .531 .604 1.447 1.516 1-5/16 1.269 1.312
7/16 9/32 .272 .291 .698 .722 5/8 .612 .625
9/16 23/64 .348 .371 .910 .938 13/16 .798 .812

Full Thread Hex Bolts Tolerance Chart


Fully Threaded Hex Bolts: Length on Tolerance
Nominal Size Nominal Length
Longer than 6"  Over 4" - 6" Over 2-1/2" - 4" Over 1" - 2-1/2" Up to 1"
1/4 - 3/8  -.18 -.10 -.06 -.04 -.03
1-1/4  -.22 -.18 -.16 -.12 -
7/8 and 1  -.20 -.16 -.14 -.10 -
7/16 & 1/2  -.18 -.10 -.08 -.06 -.03
9/16 - 3/4  -.18 -.10 -.10 -.08 -.03

Half Threaded Hex Bolts Dimensions


Half Threaded Hex Bolts Dimensions

Specification of Thread d  Pitch P b da C ds dw e k S
B A B Nomina size
L>200 (MM) 125<L≤200 (MM) L≤125 (MM) (Max) (Max) (Min) (Min) (Min) (Min) (Max) (Min) (Max) (Min) (Min)
M30 3.5 85 72 66 33.4 0.8 0.2   29.5 42.7 50.85 19.1 18.3 46 45
M24 3 73 60 54 26.4 0.8 0.2 23.7 23.5 33.6 33.2 39.98 39.55 15.2 14.8 15.4 14.7 36 35.38 35
M22 2.5 69 56 50 24.4 0.8 0.2 21.7 21.5 30 29.5 35.72 35.03 14.2 13.8 14.4 13.7 32 31.61 31
M20 2.5 65 52 46 22.4 0.8 0.2 19.7 19.5 28.2 27.7 33.53 32.95 12.7 12.3 12.9 12.2 30 29.67 29.16
M18 2.5 61 48 42 20.2 0.8 0.2 17.7 17.6 25.3 24.8 30.14 29.56 11.7 11.3 11.9 11.2 27 26.67 26.16
M16 2 57 44 38 17.7 0.8 0.2 15.7 15.6 22.5 22 26.75 26.17 10.2 9.82 10.3 9.71 24 23.67 23.16
M14 2 53 40 34 15.7 0.6 0.15 13.7 20.5 24.49 8.98 8.62 22 21.67
M12 1.75 49 36 30 13.7 0.6 0.15 11.7 17.4 21.1 7.68 7.32 19 18.67
M10 1.5 45 32 26 11.2 0.6 0.15 9.78 15.6 18.9 6.58 6.22 17 16.73
M8 1.25 28 22 9.2 0.6 0.15 7.78 11.6 14.38 5.45 5.15 13 12.73
M6 1 24 18 6.8 0.5 0.15 5.82 8.9 11.05 4.15 3.85 10 9.78
M4 0.7 14 4.7 0.4 0.15 3.82 5.9 7.66 2.92 2.68 7 6.78
M2 0.4 10 2.6 0.25 0.1 1.86 3.2 4.32 1.52 1.28 4 3.82

Half Thread Hex Bolt Weight Chart


Weight in Killogram Per 1000 Piece
Nominal Sizes M72 M64 M60 M56 M52 M48 M45 M42 M36 M30 M24 M22 M20 M18 M16 M12 M10
50 - - - - - - - - 795.00 513.25 265.00 222.00 178.25 139.00 107.00 57.02 40.60
75 - - - - - - - 1445.00 995.00 639.50 355.00 287.00 229.50 179.00 144.00 79.02 56.10
100 - - - 3400.00 2640.00 2360.00 2080.00 1720.00 1195.00 769.50 445.00 352.00 280.75 219.00 184.00 101.02 71.60
150 7750.00 5910.00 5120.00 4350.00 3490.00 3060.00 2530.00 2240.00 1570.00 1045.75 625.00 477.00 383.25 301.00 264.00 145.40 102.60
200 9300.00 7160.00 6220.00 5300.00 4340.00 3760.00 2980.00 2760.00 1970.00 1322.00 805.00 602.00 485.75 381.00 344.00 190.00 133.60
250 10850.00 8410.00 7320.00 6250.00 5190.00 4460.00 3430.00 3280.00 2370.00 1598.25 985.00 727.00 588.25 461.00 424.00 235.00 164.60
300 12400.00 9660.00 8420.00 7200.00 6040.00 5160.00 3880.00 3800.00 2770.00 1874.50 1165.00 852.00 690.75 541.00 504.00 280.00 195.60
350 13950.00 10910.00 9520.00 8150.00 6890.00 5860.00 4330.00 4320.00 3170.00 2150.75 1345.00 977.00 793.25 621.00 584.00 325.00 226.60
400 15500.00 12160.00 10620.00 9100.00 7740.00 6560.00 4780.00 4840.00 3570.00 2427.00 1525.00 1102.00 895.75 701.00 664.00 370.00 257.60

Advantages of Full Thread Bolts


  • Maximum Grip Strength
  • High Tensile Strength
  • Better Load Distribution
  • Simplified inventory management

Advantages of Half Thread Bolts


  • Reduced Stress Concentration
  • Better Shear Resistance
  • Ideal for Alignment Applications
  • Precise alignment control