Introduction
Quick Answer: When a specific thread size is required for design, manufacturing, inspection, or component selection, general thread standards are not always enough.
When a specific thread size is required for design, manufacturing, inspection, or component selection, general thread standards are not always enough. Engineers often need the exact dimensions and specifications of an individual thread size.
The LCA Thread Specifications Library provides dedicated technical reference pages for individual thread sizes, including metric and Unified thread specifications.
Each specification page is designed to provide the dimensional information needed to understand, identify, compare, and specify a particular thread.
What You’ll Find on Each Specification Page
Each individual thread specification page is structured around practical engineering information.
Depending on the applicable standard, a page may include:
Thread Designation
The standardized name or designation of the thread.
Nominal Diameter
The nominal size used to identify the thread.
Thread Pitch / TPI
The spacing between adjacent thread features or the number of threads per inch.
Major Diameter
The largest thread diameter.
Pitch Diameter
The theoretical diameter controlling the functional fit of mating threads.
Minor Diameter
The smallest thread diameter.
Thread Angle
The included angle of the thread profile.
Thread Class & Tolerance
The applicable tolerance and fit classification.
Browse Thread Specifications
ISO Metric Thread Specifications
Browse individual metric thread sizes.
Common Metric Sizes
Each size may have multiple pitch options depending on the applicable ISO standard.
Explore ISO Metric Thread Specifications →
Metric Coarse Thread Specifications
Common examples include:
Explore Metric Coarse Specifications →
Metric Fine Thread Specifications
Common examples include:
Explore Metric Fine Specifications →
Unified Thread Specifications
UNC Specifications
Examples:
UNF Specifications
Examples:
UNEF Specifications
Examples:
LCA Engineering Services
Selecting the right thread is only one aspect of successful product integration.
LCA provides engineering support throughout the development process, helping customers optimize both the mechanical and electrical performance of threaded EMI components.
Frequently Asked Questions
Q1: What information is included in a thread specification?
A thread specification may include nominal diameter, pitch or TPI, major diameter, pitch diameter, minor diameter, thread angle, tolerance, thread class, and other standard-specific dimensions.
Q2: What is the difference between a thread standard and a thread specification?
A thread standard defines an entire thread system, such as ISO Metric or UNC.
A thread specification describes a particular thread size within that system, such as M10 × 1.5 or #4-40 UNC.
Q3: Why do I need the pitch as well as the diameter?
Multiple thread sizes can have the same or similar nominal diameter but different pitches. Diameter alone is therefore insufficient to identify a thread.
Q4: Are all dimensions on a specification page actual measured values?
Not necessarily. Many published dimensions are basic or theoretical values derived from the applicable standard. Actual manufactured components are subject to specified tolerances.
Related Thread Resources
Thread Definitions
Understand Major Diameter, Pitch Diameter, Thread Pitch, Thread Class, and other engineering terms.
Thread Standards
Learn about international thread systems and specifications.
Thread Engineering Guides
Learn how to identify, measure, compare, and select threads.
Explore Thread Engineering Guides →
Thread Charts
Quickly reference common thread sizes, pitches, diameters, and other data.
Continue Exploring the LCA Thread Engineering Center
Use the LCA Thread Specifications Library to move from general thread standards to the exact dimensions of an individual thread size.
Thread Definitions → Thread Standards → Thread Specifications → Thread Engineering Guides
Find the terminology, standard, dimensions, and engineering guidance needed to confidently specify and work with threaded components.
Engineering Support CTA: Selecting a threaded EMI filter or feedthrough capacitor? Share the thread standard and size, panel thickness, voltage/current, capacitance, and environmental requirements with LCA engineers. View Thread Mount Feedthrough Filters
