5/16-32 UNEF Thread Quick Specifications
| Parameter | Specification | |
| Thread Standard | Unified Thread Standard (UTS) | |
| Thread Series | UNEF | |
| Nominal Size | 5/16 | |
| Thread Designation | 5/16-32 UNEF | |
| Threads Per Inch (TPI) | 32 | |
| Major Diameter | 0.312 in | 7.925 mm |
| Pitch | 0.0313 in | 0.795 mm |
| Pitch Diameter | 0.2917 in | 7.409 mm |
| Minor Diameter | 0.2748 in | 6.98 mm |
| Thread Height | 0.0169 in | 0.429 mm |
| Addendum | 0.0101 in | 0.257 mm |
| Thread Angle | 60° | |
| Common Classes | 2A / 2B | |
| Typical Use | Precision electronic assemblies | |
Introduction
The 5/16-32 UNEF thread is one of the most widely used Unified National Extra Fine (UNEF) thread sizes in high-reliability electronic equipment, particularly for thread-mount feedthrough capacitors, EMI filters, RF shielding assemblies, and other precision panel-mounted components.
This page provides a complete engineering reference for 5/16-32 UNEF thread dimensions and specifications, including thread designation, major diameter, pitch, threads per inch (TPI), minor diameter, tolerance classes.
For engineers selecting threaded mounting solutions for electronic components such as feedthrough filters, EMI filters, RF shielding components, and precision assemblies, understanding the 5/16-32 UNEF specification helps ensure proper mechanical compatibility, reliable installation, and long-term performance.
Quick Answer: The 5/16-32 UNEF thread is one of the most widely used Unified National Extra Fine (UNEF) thread sizes in high-reliability electronic equipment, particularly for thread-mount feedthrough capacitors, EMI filters, RF shielding assemblies, and other precision panel-mounted components.
A 5/16-32 UNEF thread is a Unified National Extra Fine (UNEF) screw thread defined by the Unified Thread Standard (UTS).
The designation means:
- 5/16indicates the nominal major diameter
- 32indicates 32 threads per inch (TPI)
- UNEFindicates Unified National Extra Fine thread series
5/16-32 UNEF Thread Tolerance Classes
Thread tolerance determines how tightly two mating components fit together.
The Unified Thread Standard defines several tolerance classes.
Class 2A / 2B Threads
Class 2 is the most commonly used commercial tolerance.
External Thread: 5/16-32 UNEF-2A
Internal Thread: 5/16-32 UNEF-2B
Advantages:
- Good interchangeability
- Reliable assembly
- Suitable for mass production
- Lower manufacturing cost
Typical applications:
- EMI filter mounting
- Feedthrough capacitor installation
- Industrial electronic equipment
- General instrumentation
Most commercial fasteners use Class 2.
Class 3A / 3B Threads
Class 3 provides a tighter fit.
External Thread: 5/16-32 UNEF-3A
Internal Thread: 5/16-32 UNEF-3B
They are typically selected when requirements include:
- Higher positional accuracy
- Reduced movement between mating parts
- Precision adjustment
- Aerospace or military specifications
However, tighter tolerances also mean:
- Higher machining requirements
- More expensive inspection
- Greater sensitivity to contamination
5/16-32 UNEF vs Similar Thread Sizes
Engineers often need to determine whether another thread specification can replace 5/16-32 UNEF.
5/16-32 UNEF vs M8 × 1
| Parameter | 5/16-32 UNEF | M8 × 1 |
| Standard | Unified | Metric ISO |
| Major Diameter | 7.925 mm | 8 mm |
| Pitch | 0.795 mm | 1 mm |
| Pitch Diameter | 7.409 mm | 7.35 mm |
| Minor Diameter | 6.98 mm | 6.917 mm |
| Thread Height | 0.429 mm | 0.541 mm |
| Thread Angle | 60° | 60° |
Frequently Asked Questions (FAQ)
Q1. Is 5/16-32 UNEF the same as 5/16-24 UNF?
No. Although both threads have the same nominal diameter (5/16 inch), they have different pitches.
Q2. What is the difference between UNF and UNEF?
The difference is thread pitch. UNEF has more threads per inch than UNF. UNEF is typically used where precision and compact mounting are required.
Q3. What tolerance class is commonly used for 5/16-32 UNEF?
The most common tolerance class is:
- External thread: 5/16-32 UNEF-2A
- Internal thread: 5/16-32 UNEF-2B
Class 3A/3B is used when tighter precision is required.
Q4. Is 5/16-32 UNEF suitable for EMI filters?
Yes. It is commonly used in:
- Feedthrough capacitors
- Thread mount EMI filters
- RF shielding components
- Panel-mounted electronic assemblies
Its fine pitch allows compact installation and reliable mechanical retention.
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
