Standard of machine screw pitch is the distance from the crest of one thread to the next.

The major diameter is the external thread diameter after thread rolling processing.

Standard Of Machine Screw Pitch and Thread Rolling Blank Diameter and Major Diameter for Metric Thread UNC UNF

Thread rolling blank diameter is the material diameter before thread rolling processing.

Standard Of Machine Screw Pitch and Thread Rolling Blank Diameter and Major Diameter for Metric Thread UNC UNF Standard Of Machine Screw Pitch and Thread Rolling Blank Diameter and Major Diameter for Metric Thread UNC UNF

The metric system is an internationally adopted decimal system of measurement. It is in widespread use, and where it is used, it is the only or most common system of weights and measures. It is now known as the International System of Units (SI). It is used to measure everyday things such as the mass of a sack of flour, the height of a person, the speed of a car, and the volume of fuel in its tank. It is also used in science, industry, and trade.

STANDARD OF MACHINE SCREW 2A (60° Thread)  Metric – Coarse
(P) （D）Major Diameter (d) Rolling Diameter
SIZE Pitch MAX MIN MAX MIN
M2 0.40 1.98 1.89 1.72 1.69
M2.3 0.40 2.28 2.19 2.02 1.99
M2.5 0.45 2.48 2.38 2.18 2.15
M3 0.50 2.98 2.88 2.64 2.61
M3.5 0.60 3.47 3.36 3.06 3.03
M4 0.70 3.98 3.84 3.49 3.45
M4.5 0.75 4.47 4.34 3.96 3.92
M5 0.80 4.98 4.83 4.43 4.38
M6 1.00 5.97 5.82 5.30 5.25
M7 1.00 6.97 6.82 6.30 6.25
M8 1.25 7.96 7.79 7.12 7.07
M9 1.25 8.96 8.79 8.12 8.07
M10 1.50 9.96 9.77 8.97 8.91
M11 1.50 10.97 10.73 9.97 9.91
M12 1.75 11.95 11.76 10.79 10.73
M14 2.00 13.95 13.74 12.63 12.56
M16 2.00 15.95 15.74 14.63 14.56
M18 2.50 17.95 17.71 16.31 16.23
M20 2.50 19.95 19.71 18.31 18.23
M22 2.50 21.95 21.71 20.31 20.23
M24 3.00 23.94 23.68 21.98 21.90
M27 3.00 26.94 26.68 24.98 24.89
M30 3.50 29.94 29.66 27.66 27.56
M33 3.50 32.94 32.66 30.65 30.56

 

STANDARD OF MACHINE SCREW 2A (60° Thread)  Metric – Fine
(P) （D）Major Diameter (d) Rolling Diameter
SIZE Pitch MAX MIN MAX MIN
M4 0.50 3.97 3.86 3.62 3.58
M4.5 0.50 4.47 4.36 4.12 4.08
M5 0.50 4.97 4.86 4.62 4.58
M6 0.75 5.97 5.85 5.45 5.41
M7 0.75 6.97 6.85 6.45 6.41
M8 1.00 7.97 7.83 7.29 7.24
M9 1.00 8.97 8.83 8.29 8.24
M10 1.25 9.96 9.81 9.12 9.07
M10 1.00 9.97 9.82 9.28 9.23
M12 1.25 11.97 11.76 11.12 11.07
M12 1.50 11.96 11.79 10.95 10.89
M14 1.50 13.96 13.79 12.95 12.89
M16 1.50 15.96 15.79 14.95 14.89
M18 2.00 17.95 17.65 16.62 16.54
M18 1.50 17.95 17.78 16.93 16.86
M20 2.00 19.95 19.65 18.62 18.54
M20 1.50 19.95 19.78 18.92 18.85
M22 1.50 21.95 21.78 20.92 20.85
M24 1.50 23.95 23.78 22.92 22.85
M26 1.50 25.95 25.78 24.93 24.85
M27 1.50 26.95 26.78 25.93 25.85
M28 1.50 27.95 27.78 26.93 26.85
M30 1.50 29.95 29.78 28.93 28.85

 

U.N.C.  STANDARD OF MACHINE SCREW 2A (60° Thread)
(T) （D）Major Diameter (d) Rolling Diameter
SIZE Threads MAX MIN MAX MIN
NO:1 64 1.838 1.743 1.58 1.56
NO:2 56 2.169 2.066 1.87 1.85
NO:3 48 2.496 2.383 2.14 2.11
NO:4 40 2.824 2.695 2.40 2.37
NO:5 40 3.154 3.026 2.72 2.69
NO:6 32 3.484 3.333 2.94 2.91
NO:8 32 4.142 3.991 3.60 3.57
NO:10 24 4.800 4.618 4.09 4.05
NO:12 24 5.461 5.279 4.75 4.70
  1/4 20 6.322 6.117 5.50 5.45
  5/16 18 7.907 7.687 6.98 6.93
  3/8 16 9.491 9.254 8.45 8.40
  7/16 14 11.076 10.816 9.89 9.83
  1/2 13 12.661 12.386 11.39 11.32
  9/16 12 14.246 13.958 12.87 12.80
  5/8 11 15.834 15.528 14.33 14.26
  3/4 10 19.004 18.677 17.34 17.27
  7/8 9 22.176 21.824 20.34 20.26
  1 8 25.349 24.969 23.28 23.20
  11/8 7 28.519 28.103 26.16 26.07

 

U.N.F.  STANDARD OF MACHINE SCREW 2A (60° Thread)
(T) （D）Major Diameter (d)  Rolling Diameter
SIZE Threads MAX MIN MAX MIN
NO:2 64 2.169 2.073 1.91 1.89
NO:3 56 2.496 2.393 2.20 2.17
NO:4 48 2.827 2.713 2.47 2.44
NO:5 44 3.157 3.036 2.76 2.73
NO:6 40 3.484 3.356 3.05 3.02
NO:8 36 4.145 4.006 3.66 3.63
NO:10 32 4.803 4.651 4.26 4.23
NO:12 28 5.461 5.296 4.85 4.81
  1/4 28 6.324 6.160 5.72 5.68
  5/16 24 7.909 7.727 7.20 7.16
  3/8 24 9.497 9.315 8.76 8.74
  7/16 20 11.079 10.874 10.23 10.18
  1/2 20 12.666 12.462 11.82 11.76
  9/16 18 14.251 14.031 13.31 13.25
  5/8 18 15.839 15.619 14.89 14.83
  3/4 16 19.011 18.774 17.95 17.89
  7/8 14 22.184 21.923 20.98 20.91
  1 12 25.254 25.065 23.95 23.87
 11/8 12 28.529 28.240 27.12 27.05

 

S.M.  STANDARD OF MACHINE SCREW 2A  (60° Thread)
(T) （D）Major Diameter (d)  Rolling Diameter
SIZE Threads MAX MIN MAX MIN
  5/64 64 1.984 1.904 1.71 1.69
  3/32 56 2.381 2.306 2.07 2.04
  1/8 48 3.175 3.065 2.81 2.78
  1/8 44 3.175 3.055 2.78 2.75
  1/8 40 3.175 3.045 2.74 2.71
  9/64 40 3.572 3.442 3.13 3.10
 11/64 40 4.366 4.236 3.92 3.89
 11/64 32 4.366 4.206 3.82 3.79
  3/16 40 4.762 4.632 4.32 4.29
  3/16 32 4.762 4.602 4.22 4.19
  3/16 28 4.762 4.602 4.14 4.11
  3/16 24 4.762 4.602 4.04 4.01
 13/64 32 5.159 4.999 4.60 4.57
  7/32 32 5.556 5.396 5.01 4.98
 15/64 28 5.953 5.773 5.32 5.29
  1/4 40 6.350 6.220 5.90 5.87
  1/4 28 6.350 6.170 5.72 5.69
  1/4 24 6.350 6.170 5.62 5.59
  9/32 28 7.144 6.954 6.51 6.48
  9/32 20 7.144 6.954 6.28 6.25
  5/16 24 7.938 7.748 7.21 7.18
  5/16 18 7.938 7.748 6.98 6.94

 

B.S.W.  STANDARD OF MACHINE SCREW 2A (55° Thread)
(P) （D）Major Diameter (d)  Rolling Diameter
SIZE Pitch MAX MIN MAX MIN
  1/8 40 3.145 3.030 2.72 2.70
  5/32 32 3.945 3.795 3.40 3.38
  3/16 24 4.732 4.592 4.03 4.00
  1/4 20 6.320 6.165 5.48 5.45
  5/16 18 7.905 7.737 6.97 6.94
  3/8 16 9.490 9.312 8.44 8.40
  7/16 14 11.074 10.883 9.88 9.84
  1/2 12 12.662 12.456 11.27 11.22
  9/16 12 14.247 14.039 12.86 12.81
  5/8 11 15.832 15.614 14.33 14.27
  3/4 10 19.004 18.770 17.34 17.28
  7/8 9 22.225 21.798 20.34 20.28
  1 8 25.400 25.130 23.29 23.23

 

B.A.  STANDARD OF MACHINE SCREW  (47.5° Thread)
(P) （D）Major Diameter (d)  Rolling Diameter
SIZE Pitch MAX MIN MAX MIN
0 BA 1.00 5.97 5.78 5.33 5.28
1 BA 0.90 5.27 5.10 4.70 4.65
2 BA 0.81 4.67 4.52 4.15 4.11
3 BA 0.73 4.07 3.94 3.60 3.56
4 BA 0.66 3.57 3.45 3.15 3.12
5 BA 0.59 3.17 3.05 2.79 2.76
6 BA 0.53 2.77 2.67 2.43 2.40
7 BA 0.48 3.47 2.38 2.17 2.14
8 BA 0.43 2.17 2.09 1.91 1.88