METRIC SELF TAPPING SCREW SIZES

Metric self tapping screw sizes chart according to ISO 1478 standard for ISO metric threads. Dimensions are in millimeters.

Thread
Size		 ST 1.5 ST 1.9 ST 2.2 ST 2.6
P≈ 0.5 0.6 0.8 0.9
d1 max. 1.52 1.90 2.24 2.57
min. 1.38 1.76 2.10 2.43
d2 max. 0.91 1.24 1.63 1.90
min. 0.84 1.17 1.52 1.80
d3 max. 0.79 1.12 1.47 1.73
min. 0.69 1.02 1.37 1.60
c max. 0.1 0.1 0.1 0.1
r note 1≈ - - - -
yref note 2 Type
C		 1.4 1.6 2 2.3
Type
F		 1.1 1.2 1.6 1.8
Type
R		 - - - -
Number note 3 0 1 2 3


Thread
Size		 ST
2.9		 ST
3.3		 ST
3.5		 ST
3.9		 ST
4.2
P≈ 1.1 1.3 1.3 1.3 1.4
d1 max. 2.90 3.30 3.53 3.91 4.22
min. 2.76 3.12 3.35 3.73 4.04
d2 max. 2.18 2.39 2.64 2.92 3.10
min. 2.08 2.29 2.51 2.77 2.95
d3 max. 2.01 2.21 2.41 2.67 2.84
min. 1.88 2.08 2.26 2.51 2.69
c max. 0.1 0.1 0.1 0.1 0.1
r note 1≈ - - 0.5 0.6 0.6
yref note 2 Type
C		 2.6 3 3.2 3.5 3.7
Type
F		 2.1 2.5 2.5 2.7 2.8
Type
R		 - - 2.7 3 3.2
Number note 3 4 5 6 7 8

Thread
Size		 ST
4.8		 ST
5.5		 ST
6.3		 ST
8		 ST
9.5
P≈ 1.6 1.8 1.8 2.1 2.1
d1 max. 4.80 5.46 6.25 8.00 9.65
min. 4.62 5.28 6.03 7.78 9.43
d2 max. 3.58 4.17 4.88 6.20 7.85
min. 3.43 3.99 4.70 5.99 7.59
d3 max. 3.30 3.86 4.55 5.84 7.44
min. 3.12 3.68 4.34 5.64 7.24
c max. 0.15 0.15 0.15 0.15 0.15
r note 1≈ 0.7 0.8 0.9 1.1 1.4
yref note 2 Type
C		 4.3 5 6 7.5 8
Type
F		 3.2 3.6 3.6 4.2 4.2
Type
R		 3.6 4.3 5 6.3 -
Number note 3 10 12 14 16 20

Note 1: Dimension r is a reference. The end may not be perfectly spherical but shall not be sharp.

Note 2: Incomplete thread length.

Note 3: Former thread designation, for information only.

Note 4: All dimensions are in mm.

Metric Self Tapping Screw Thread Self tapping screw thread end alternatives

Supplements:

Reference:

  • ISO 1478:1999, Tapping screws thread