#1-64 UNC Thread Quick Specifications
| Parameter | Specification | |
| Thread Standard | Unified Thread Standard (UTS) | |
| Thread Series | UNC | |
| Nominal Size | #1 | |
| Thread Designation | 1-64 UNC | |
| Threads Per Inch (TPI) | 64 | |
| Major Diameter | 0.0730 in | 1.854 mm |
| Pitch | 0.0156 in | 0.396 mm |
| Pitch Diameter | 0.0629 in | 1.598 mm |
| Minor Diameter | 0.0544 in | 1.382 mm |
| Thread Height | 0.0085 in | 0.216 mm |
| Addendum | 0.0051 in | 0.13 mm |
| Thread Angle | 60° | |
| Common Classes | 2A / 2B | |
| Typical Use | Miniature precision assemblies and electronic hardware | |
Introduction
The #1-64 UNC thread belongs to the Unified Thread Standard (UTS), which is primarily used for inch-based threaded components in North America and is also found in specialized international applications.
This page provides an engineering reference for #1-64 UNC thread dimensions and specifications, including thread designation, major diameter, pitch, threads per inch (TPI), pitch diameter, minor diameter, and tolerance classes.
Because of its small diameter and fine thread spacing, #1-64 UNC is typically used where compact fastening and limited installation space are important considerations.
Common applications may include:
- Miniature electronic assemblies
- Precision instruments
- Small mechanical components
- Electronic hardware
- Instrumentation equipment
- Specialized precision assemblies
Quick Answer: The #1-64 UNC thread belongs to the Unified Thread Standard (UTS), which is primarily used for inch-based threaded components in North America and is also found in specialized international applications.
#1-64 UNC is a Unified National Coarse thread specification where:
- #1indicates the nominal screw size
- 64indicates 64 threads per inch (TPI)
- UNCindicates the Unified National Coarse thread series
A 1-64 UNC thread has a nominal major diameter of approximately 0.0730 inches (1.854 mm) and uses the standard 60-degree Unified thread profile.
With 64 threads per inch, the thread spacing is approximately 0.396 mm, making this a compact thread specification suitable for miniature components and applications where space is limited.
1-64 UNC Thread Tolerance Classes
Thread tolerance determines how closely an external thread fits with its corresponding internal thread.
The Unified Thread Standard defines several tolerance classes for external and internal threads.
Class 2A / 2B Threads
Class 2 is commonly used for general commercial applications.
External Thread: 1-64 UNC-2A
Internal Thread: 1-64 UNC-2B
Characteristics:
- Balanced fit
- Good manufacturability
- Suitable for general-purpose applications
Class 3A / 3B Threads
Class 3 provides a tighter tolerance than Class 2.
External Thread: #1-64 UNC-3A
Internal Thread: #1-64 UNC-3B
Applications:
- Precision equipment
- Specialized mechanical assemblies
- Applications requiring tighter thread control
Characteristics:
- Reduced clearance
- Higher dimensional accuracy
- Higher manufacturing requirements
1-64 UNC vs Similar Thread Sizes
Engineers may compare #1-64 UNC with nearby miniature inch or metric thread sizes when selecting a suitable fastening solution.
1-64 UNC vs M2 × 0.4
| Parameter | 1-64 UNC | M2 × 0.4 |
| Standard | Unified | Metric ISO |
| Major Diameter | 1.845 mm | 2.00 mm |
| Pitch | 0.396 mm | 0.4 mm |
| Pitch Diameter | 1.598 mm | 1.74 mm |
| Minor Diameter | 1.382 mm | 1.567 mm |
| Thread Height | 0.216 mm | 0.217 mm |
| Thread Angle | 60° | 60° |
Although the pitch values are very close, #1-64 UNC and M2 × 0.4 are different thread specifications. Their nominal diameters and thread standards are different, so they should not be treated as directly interchangeable without confirming the mating components and application requirements.
Frequently Asked Questions (FAQ)
Q1. What does #1-64 UNC mean?
#1-64 UNC is a Unified National Coarse thread designation. The number #1 represents the screw size, 64 indicates 64 threads per inch (TPI), and UNC identifies the Unified National Coarse thread series.
A 1-64 UNC thread has a nominal major diameter of approximately 0.0730 inches (1.85 mm) and uses a 60-degree Unified thread profile.
Q2. Is #1-64 UNC a metric thread?
No. #1-64 UNC is an inch-based Unified thread specification, not a metric thread.
Its pitch is approximately 0.396 mm, which is close to M2 × 0.4, but the two specifications have different nominal diameters and should not be assumed to be interchangeable.
Q3. What tolerance class is commonly used for 1-64 UNC?
Common Unified thread classes include:
- External thread: 1-64 UNC-2A
- Internal thread: 1-64 UNC-2B
Class 3A/3B may be specified when a tighter fit or higher dimensional control is required.
Q4. Can LCA provide EMI filters with 1-64 UNC threads?
Yes. LCA supports customized EMI feedthrough filter designs with various thread configurations, including miniature inch and metric thread options.
Customization may include:
- Thread size
- Housing dimensions
- Electrical parameters
- Sealing structure
- Plating options
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
Related Engineering Resources
- #8-32 UNC Thread Dimensions
- 3/8-16 UNC Thread Dimensions
- 1/4-28 UNF Thread Dimensions
- #12-32 UNEF Thread Dimensions
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