METRIC SELF TAPPING SCREW SIZES


Metric self tapping screw sizes according to ISO 1478:1999 standard for ISO metric threads. Dimensions are in millimeters.


Metric Self Tapping Screw Thread
Self tapping screw thread end alternatives

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.


Supplements:

Link Usage
Metric Self Tapping Screw Thread Dimensions Calculator Calculator form of the metric self tapping screw sizes chart.

Reference:

  • ISO 1478:1999, Tapping screws thread