SELF TAPPING SCREW THREAD DIMENSIONS (METRIC)


"Metric Self Tapping Screw Thread Dimensions " Calculator has been developed to show dimensions of metric self tapping screw thread according to the ISO standards.

Some important notes from the ISO standards:

- ISO 1478 specifies the thread and thread ends for self tapping screws (sheet metal screws) with thread sizes from ST1.5 to ST9.5 inclusive.

- Self tapping screw thread designation example for thread size ST 5.5 : Tapping screw thread ISO 1478 - ST5.5

Calculator:

INPUT PARAMETERS
Nominal Self Tapping Screw Size

 


Metric Self Tapping Screw Thread
RESULTS
Parameter Value
Nominal Screw Size ---
p ---
d1,max ---
d1,min ---
d2,max ---
d2,min ---
d3,max ---
d3,min ---
cmax ---
r note1 ---
yref, Type C note 2 ---
yref, Type F note 2 ---
yref, Type R note 2 ---
Number note 3 ---

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.



Definitions:

Self tapping screw: A type of screw which can tap its own hole as it is screwed into it.

Self tapping screw thread end alternatives:

Root contour for ISO general purpose metric screw threads
Metric self tapping screw thread ends
Reference:
  • ISO 1478:1999, Tapping screws thread