Page 14 - THREADING CATALOG

INTRODUCTION
INTRODUCTION In thread manufacturing, permissible limits are defined for Tolerance System ISO Standard
Thread Accuracy

the actual thread profile’s deviations from the theoretical
In accordance with the ISO standard, threading
thread profile. To ensure correct threading operations,
accuracy is determined by the combination of
the thread profile cannot cross the theoretical profile,
tolerance grade and tolerance position.
and therefore, this permissible limit is set by tolerances.
The external and internal thread should only contact
according to major, pitch and minor diameters and
the sides of the threaded profile, therefore the main
are different for internal and external threads.
parameter that influences thread tolerance is the pitch
diameter. Tolerances on major and minor diameters Tolerance grades are classified by numbers
External Threads
Internal Threads
are set in such a way as to exclude the possibility of tolerance tolerance
collision on the tops and bottoms of the thread. Each dimension grade dimension grade
thread standard contains a different tolerance method. minor major
diameter 4, 5, 6, 7, 8 diameter 4, 6, 8
ISCAR provides tools for thread production at 3, 4, 5, 6,
all standards and in all accuracy classes pitch diameter 4, 5, 6, 7, 8 pitch diameter 7, 8, 9
Tolerance positions are classified by letters and
are different for external and internal threads.
Gender Tolerance Position
internal threads G, H
external threads e, f, g, h

ISCAR
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