Threads varies in many ways. In the following we explain the basics of thread. You can also check out our FAQ section for thread.
Every matched pair of threads, external and internal, can be described as male and female. For example, a screw has male thread, while the matching hole has female thread.
The helix of a thread twists in one of two possible directions. Most threads are oriented so that the threaded item when seen from a point of view on the axis through the center of the helix, moves away from the viewer when it is turned in a clockwise direction and moves towards the viewer when it is turned counter-clockwise.
By convention right-handedness is the default handedness for screw threads. Most threaded parts and fasteners therefore have right-handed threads.
The type of thread can be identified by the following characteristics: parallel and tapered design (see images right).
The pitch is the distance from the crest of one thread to the next in milimeters (mm).
TPI (threads per inch) is used by inch thread.
The major diameter is determined by the thread tips.
The minor diameter is determined by the groove of the thread.
The pitch diameter is the distance between the tips of two opposite flanks or the length of the centreline of the profile.
The flank angle is the angle between the flank of a screw thread and the perpendicular line to the axis of the screw. Tapered threads have a taper angle. This is the angle between the taper and the center axis of the pipe.
The outermost part of the thread is called 'crest', the innermost part of the thread is called 'root'.
DIMENSIonS of thread TYPES
M - ISO THREAD (METRIC)
M Coarse Thread ISO 724 (DIN 13-1)
M Fine Thread ISO 724 (DIN 13-2 to 11)
NPT - PIPE THREAD
NPT ANSI B1.20.1
NPTF ANSI B1.20.3
G/R/RP - WHITWORTH THREAD (BSPP/BSPT)
G = BSPP ISO 228 (DIN 259)
R/Rp/Rc = BSPT ISO 7 (DIN 2999 replaced by EN10226)
UNC/UNF - UNIFIED NATIONAL THREAD
UNC ANSI B1.1
UNF ASNI B1.1
Do you need more information about the possibilities or do you want to receive a printed version?
Contact our specialists: