Screw Thread Designation

Screw thread designation is a systematic method used to identify and specify the characteristics of screw threads. It involves a standardized set of symbols and numerical values that convey essential information about the thread’s dimensions, shape, and other attributes. This designation ensures consistency and compatibility in threaded components, facilitating accurate communication, manufacturing, and assembly. By adhering to these standardized designations, engineers and manufacturers can effectively match and use threaded parts in various applications.

Screw Thread Designation

Unified Inch Screw Threads – Designation

Unified Inch Screw Threads – Designation
Two of the Unified screw thread forms (UN and UNR) are standardized in ASME B1.1 -2003. UNR only applies to external threads and mandates a radius on the root of the thread. The designation of screw threads in this series is standardized in the ASME B1.1 standard. Please see the standard for the most complete...
Unified Inch Screw Threads - Designation

Unified Inch Screw Threads - Designation

Two of the Unified screw thread forms (UN and UNR) are standardized in ASME B1.1 -2003. UNR only applies...
Unified Screw Threads Introduction

Unified Screw Threads Introduction

Unified (UN) screw threads are a standard form of thread used in the United States and other countries...
Nominal Size (Basic Major Diameter)

Nominal Size (Basic Major Diameter)

The nominal size is the basic major diameter of the designated thread. It can be specified as fractional...
Threads Per Inch

Threads Per Inch

The number of threads per inch is related to the pitch , it is the inverse of the pitch. In the designation,...
Thread Form Symbol

Thread Form Symbol

The Unified thread form is indicated with the UN or UNR symbol.
Thread Pitch Series Symbol

Thread Pitch Series Symbol

The thread series symbol in a Unified thread designation indicates the specific type and characteristics...
Graded Pitch Series

Graded Pitch Series

In the Unified Thread Series, graded pitch series refer to the different classifications of thread pitches...
Constant Pitch Series

Constant Pitch Series

In the Unified Thread system, pitches are available which do not fall into the graded pitch series....

Special Pitch Series

UNS threads represent unique combinations of diameter and pitch, adhering to the Unified Thread Standard...
Thread Class

Thread Class

Thread classes define how much (if any) allowance  is required between mating threads, and how large t...