Jic Thread Sizes

jic thread sizes Safety Certifications

JIC (Joint Industry Council) thread sizes are standardized to ensure compatibility and consistency across various hydraulic applications. These threads are often utilized in high-pressure fluid systems, such as those found in aviation, construction, and industrial machinery. JIC fittings are characterized by their 37-degree flare seating surface, which ensures a tight, leak-proof seal when properly assembled.

The commonly used JIC thread sizes include:
- 1/16 inch (5/16-24 UNF)
- 1/8 inch (3/8-24 UNF)
- 3/16 inch (7/16-20 UNF)
- 1/4 inch (9/16-18 UNF)
- 3/8 inch (3/4-16 UNF)
- 1/2 inch (7/8-14 UNF)
- 5/8 inch (1 1/16-12 UNF)
- 3/4 inch (1 3/16-12 UNF)
- 1 inch (1 5/16-12 UNF)
- 1 1/4 inch (1 5/8-12 UNF)
- 1 1/2 inch (1 7/8-12 UNF)
- 2 inch (2 1/2-12 UNF)

For safety and regulatory compliance, JIC fittings and systems are subject to various certifications and standards. Noteworthy certifications include:

1. ISO 8434-2: Governs flare fittings and ensures consistent global standards.
2. SAE J514: A standard by the Society of Automotive Engineers outlining the specific requirements for JIC fittings.
3. CE Certification (European Conformity): Ensures the product meets EU safety, health, and environmental requirements.
4. RoHS (Restriction of Hazardous Substances): Ensures that the fittings are free from specific hazardous materials.

Following these certifications ensures that JIC thread fittings adhere to rigorous safety and performance standards, fostering reliability and safe operation in high-pressure environments. Always refer to the manufacturer's specifications and industry standards to ensure appropriate use and compatibility.

List Reference Technical Parameters of "jic thread sizes"

JIC (Joint Industry Council) threads are commonly used in hydraulic and fluid power applications due to their reliability and versatility. They are typically found on fittings and adapters, designed primarily to connect mechanically without leakage in high-pressure systems. Below are key technical parameters associated with JIC thread sizes:

1. Thread Type: JIC threads follow the SAE J514 standard and are 37-degree flare fittings. The threads are unified and adhere to the same pitch and diameter dimensions as UN threads.

2. Size Range: JIC thread sizes typically range from 1/8 inch to 2 inches. Common sizes include 1/4", 3/8", 1/2", 5/8", 3/4", 7/8", 1", 1-1/4", 1-1/2", and 2".

3. Thread Designation: Threads are often designated by the nominal size of the fitting's tube OD (Outer Diameter). For instance, a 1/4" JIC thread corresponds to a fitting designed for a 1/4" pipe size.

4. Threads Per Inch (TPI):
- 1/8": 27 TPI
- 1/4": 20 TPI
- 3/8": 18 TPI
- 1/2": 14 TPI
- 5/8": 14 TPI
- 3/4": 12 TPI
- 7/8": 14 TPI
- 1": 12 TPI
- 1-1/4": 12 TPI
- 1-1/2": 12 TPI
- 2": 12 TPI

5. Thread Angle: JIC threads employ a 37-degree flare design, which matches the cone of the corresponding fitting for a secure seal.

6. Pressure Ratings: JIC fittings are suitable for hydraulic systems operating at pressures up to 10,000 PSI, depending on the size. Pressure ratings decrease with an increase in fitting size and temperature.

7. Material Compatibility: JIC fittings are made from materials like carbon steel, stainless steel, and brass, ensuring compatibility with a variety of fluid types and environments.

8. Sealing Mechanism: JIC fittings don't rely on thread sealant or O-rings for sealing. Instead, the metal-on-metal contact between the 37-degree flared surfaces provides the seal.

Understanding these parameters helps ensure the proper selection and application of JIC threads in various high-pressure fluid systems.

List Product features of "jic thread sizes"

Certainly! Here are the key features of "JIC Thread Sizes":

1. Standardization: JIC (Joint Industry Council) thread sizes are standardized, ensuring compatibility across various applications and industries.

2. Thread Design: Featuring 37-degree flare seating surfaces, JIC threads create a metal-to-metal seal that is reliable and leak-resistant.

3. Availability: JIC fittings and threads come in a variety of sizes, typically ranging from 1/8 inch to 2 inches, accommodating different requirements.

4. Material Versatility: Available in multiple materials such as stainless steel, carbon steel, and brass, enabling use in diverse environments and applications.

5. Pressure Range: Capable of handling high-pressure applications, JIC threads are ideal for hydraulic systems frequently experiencing high pressure.

6. Reusable Connections: The design allows fittings to be easily connected and disconnected without significant wear and tear, promoting reusability and cost-efficiency.

7. Versatility in Applications: Suited for applications in automotive, aerospace, heavy machinery, and industrial sectors, JIC threads showcase versatile utility.

8. Seal Integrity: The 37-degree flare design ensures a superior seal, reducing the risk of leaks and enhancing the overall reliability of the hydraulic systems.

9. Ease of Assembly: JIC fittings are relatively easy to assemble, facilitating quicker installation and maintenance times.

10. Corrosion Resistance: Depending on material and coating, JIC fittings can offer excellent resistance to corrosion, which is crucial for applications exposed to harsh conditions.

11. Compatibility: These thread sizes are compatible with an array of hoses and tubes, providing flexibility and convenience in system design.

By incorporating these features, JIC thread sizes offer a dependable solution for fluid and hydraulic system connections, promoting efficiency, reliability, and versatility across various demanding applications.

List Various Types of "jic thread sizes"

The Joint Industry Council (JIC) thread sizes, often referred to in hydraulic fittings and connections, come in a range of sizes and configurations. These thread sizes are standardized to ensure compatibility and interchangeability across different manufacturers and systems. JIC fittings generally have a 37-degree flare seating surface that makes them suitable for high-pressure applications. Here are some common JIC thread sizes and their corresponding nominal sizes:

1. #2 JIC (1/8” nominal size): This is typically specified as 5/16-24 threads per inch.
2. #4 JIC (1/4” nominal size): Utilizes 7/16-20 threads per inch.
3. #5 JIC (5/16” nominal size): Has 1/2-20 threads per inch.
4. #6 JIC (3/8” nominal size): Specified as 9/16-18 threads per inch.
5. #8 JIC (1/2” nominal size): This size features 3/4-16 threads per inch.
6. #10 JIC (5/8” nominal size): Comes with 7/8-14 threads per inch.
7. #12 JIC (3/4” nominal size): Uses 1-1/16-12 threads per inch.
8. #16 JIC (1” nominal size): Has 1-5/16-12 threads per inch.
9. #20 JIC (1-1/4” nominal size): Features 1-5/8-12 threads per inch.
10. #24 JIC (1-1/2” nominal size): Specified as 1-7/8-12 threads per inch.
11. #32 JIC (2” nominal size): Utilizes 2-1/2-12 threads per inch.

These JIC thread sizes are often used in applications involving hydraulic hoses, tubing, and various fluid transfer systems. The standardized sizes allow for secure, leak-proof connections that can withstand high-pressure conditions in industrial and mobile hydraulic systems.

List Application of "jic thread sizes"

JIC (Joint Industry Council) thread sizes are widely used in various industries due to their reliability and versatility in providing leak-free connections in hydraulic systems. Here are some key applications:

1. Hydraulic Systems: JIC fittings are commonly employed in hydraulic equipment because they can withstand high-pressure environments, ensuring leak-free performance. They are used in machinery such as excavators, loaders, and other construction equipment.

2. Aerospace: In the aerospace industry, JIC thread sizes are used in the hydraulic and fuel systems of aircraft. The fittings are crucial for maintaining the integrity and reliability of hydraulic systems that control various flight operations.

3. Automotive: JIC fittings are also utilized in the automotive sector, particularly in performance and custom vehicles. They are found in fuel systems, brake lines, and other hydraulic circuits to provide durable and secure connections.

4. Industrial Machinery: Factories and manufacturing plants use JIC-threaded fittings in their industrial machinery to facilitate hydraulic and pneumatic operations. They are vital in systems requiring robust and reliable connections.

5. Marine Applications: The marine industry relies on JIC fittings for hydraulic and fuel systems in boats and ships. Their corrosion resistance and ability to handle high pressures make them suitable for harsh marine environments.

6. Oil and Gas: In the oil and gas sector, JIC thread sizes are used in drilling equipment and pipelines. The fittings ensure leak-free connections, crucial for the safe and efficient transport of oil and gas.

7. Agricultural Equipment: Tractors, plows, and other agricultural machinery utilize JIC fittings in their hydraulic systems to ensure high performance and reliability in diverse working conditions.

JIC thread sizes offer versatility, reliability, and high-pressure tolerance, making them indispensable across various industries requiring robust hydraulic and pneumatic connections.

List Buyer Types of "jic thread sizes"

Sure, here are key buyer types for JIC (Joint Industry Council) thread sizes:

1. Hydraulic System Designers and Engineers:
- Needs: Precision, compatibility with extensive hydraulic systems.
- Usage: Often used in heavy machinery, construction equipment, and vehicles where robust and leak-free connections are vital.

2. Maintenance and Repair Professionals:
- Needs: Quality replacements, easy-to-install fittings, reliability.
- Usage: Perform maintenance on existing hydraulic systems, ensuring fluid systems remain operational without leaks.

3. Manufacturers of Hydraulic Equipment:
- Needs: Bulk purchases, consistent quality, reliable supply chain.
- Usage: Integrate JIC fittings into new machinery and equipment during manufacture.

4. Industrial Supply Distributors:
- Needs: Comprehensive inventory, diverse sizes and types, competitive pricing.
- Usage: Stock JIC fittings to supply various industrial clients, from small businesses to large enterprises.

5. Agriculture Equipment Providers:
- Needs: Durable, weather-resistant components.
- Usage: Equip tractors and other farm machinery with reliable hydraulic systems.

6. Automotive Industry:
- Needs: High-performance, precision fittings, adherence to safety standards.
- Usage: Utilize in vehicles for steering, braking, and other hydraulic applications.

7. Aerospace Sector:
- Needs: High-quality, lightweight, corrosion-resistant fittings.
- Usage: Use JIC thread sizes in aircraft hydraulic systems ensuring impeccable performance and safety.

8. Military and Defense Contractors:
- Needs: Extremely durable, high-specification fittings.
- Usage: Integrate these components into military vehicles and equipment.

Each buyer type emphasizes different aspects of JIC thread sizes, from precision and durability to inventory variety and compliance with specific industry standards.

List "jic thread sizes" Project Types for Different Industries

JIC (Joint Industry Council) thread sizes are a crucial component in various industries, particularly in fluid power applications. These thread sizes are standardized by SAE (Society of Automotive Engineers) and are predominantly used for hydraulic fittings. Here's a brief look at project types in different industries where JIC thread sizes are commonly implemented:

1. Automotive Industry:
- Hydraulic Systems: Used in power steering and brake systems, ensuring leak-proof fluid transfer.
- Fuel Injection Systems: Enables the delivery of fuel under high pressure with leak prevention.

2. Manufacturing Industry:
- Machinery and Robotics: Employed in hydraulic lines to power actuators and robotic arms.
- Pneumatic Systems: Utilized for connecting air compressors to various tools and machinery.

3. Aerospace Industry:
- Hydraulic Actuation Systems: Critical for flight control surfaces, landing gear, and braking systems.
- Fuel Systems: Ensures secure connections in both cryogenic and standard fuel lines, optimizing safety and performance.

4. Oil and Gas Industry:
- Drilling Equipment: Essential for hydraulic power units that drive downhole tools.
- Pipeline Systems: Used in high-pressure lines to ensure secure and leak-free connections.

5. Construction Industry:
- Heavy Machinery: Hydraulic systems in excavators, loaders, and cranes rely on JIC fittings.
- Hydraulic Lifting Equipment: Facilitates secure connections in hydraulic jacks and lifts.

6. Agricultural Industry:
- Tractors and Harvesters: Critical for hydraulic circuits powering various attachments.
- Irrigation Systems: Utilized in high-pressure connections for efficient water delivery.

7. Marine Industry:
- Steering Systems: Integral to hydraulic steering and control systems.
- Hydraulic Winches: Ensures efficient and leak-free operation in anchor handling and towing systems.

These project types underscore the versatility and reliability of JIC thread sizes across a range of industrial applications, enhancing system efficiency and safety.

jic thread sizes Accessories Upgrades and Custom Manufacturing Options

JIC (Joint Industry Council) thread sizes are essential for high-pressure hydraulic applications. Common sizes range from 1/8-27 NPTF to 1-5/8-12 UN, accommodating diverse industrial needs. The compatibility and sealing efficiency of JIC fittings make them popular in various sectors, including agricultural, automotive, and aerospace industries.

Accessories:
1. Caps and Plugs: Protect threads and seals from contamination and damage.
2. Adapters: Allow conversion between different thread types and sizes.
3. O-Rings and Seals: Enhance the sealing capability for leak-free connections.

Upgrades:
1. Material Enhancements: Upgrade to stainless steel or brass for superior corrosion resistance and durability under extreme conditions.
2. Coatings: Apply specialty coatings like zinc-nickel for increased longevity and performance in harsh environments.
3. Precision Machining: Increases fitting accuracy, ensuring more reliable and efficient connections.

Custom Manufacturing Options:
1. Bespoke Designs: Tailor fittings to specific industry requirements, including non-standard thread sizes and unique shapes.
2. Integrate Valves and Sensors: Customize fittings to include integrated sensors or valves for real-time system monitoring and control.
3. Batch Production: Flexibility in manufacturing batch sizes, from small runs for prototyping to large-scale production, ensuring solutions fit project constraints.

Custom JIC thread fittings and accessories address unique application challenges, enhancing performance, safety, and reliability in hydraulic systems. Upgrades in materials and precision offer extended service life. Whether needing standard accessories or bespoke manufacturing solutions, these options provide the versatility to optimize system efficiency and integrity.

List Quality Control and The Manufacturing Process of "jic thread sizes"

Quality Control and Manufacturing Process of JIC Thread Sizes

#### Manufacturing Process

1. Material Selection: Choose high-grade steel or stainless steel for durability and corrosion resistance.
2. Cutting: Use CNC machines to cut the raw material to the required size.
3. Forging: Forge the material to create the basic shape of the JIC fitting and thread.
4. Machining: Precisely machine the internal and external threads to meet JIC standards (37-degree flare angle).
5. Heat Treatment: Subject the fittings to heat treatment to enhance their mechanical properties.
6. Surface Treatment: Apply coatings such as zinc plating or anodizing for corrosion resistance.
7. Inspection: Perform initial inspection to verify dimensions and thread accuracy.

#### Quality Control

1. Incoming Material Inspection: Verify material quality through certificates and random sampling.
2. Dimensional Checks: Use calipers, micrometers, and go/no-go gauges to ensure thread dimensions meet JIC standards.
3. Thread Surface Inspection: Inspect thread surfaces for defects like burrs, using optical instruments.
4. Pressure Testing: Test the fittings under high-pressure conditions to ensure they can withstand operational pressures without leaking.
5. Surface Finish Testing: Ensure coatings are uniformly applied and check for adequate thickness using coating thickness gauges.
6. Random Sampling: Conduct random sampling of batches to check for consistency and adherence to specifications.
7. Final Inspection: Perform a comprehensive inspection of each batch before packaging, focusing on dimensions, threads, and surface quality.

By integrating these quality control measures into the manufacturing process, JIC thread sizes ensure they meet the stringent requirements necessary for reliable hydraulic and fluid transfer applications.

How to use "jic thread sizes"

JIC (Joint Industry Council) thread sizes are standardized thread formats used primarily in hydraulic systems for fittings and adapters. Here's a concise guide on how to use them:

1. Identify JIC Threads: JIC threads are identified by their 37° flare seating and the thread sizes are based on OD (outer diameter) and threads per inch (TPI). Common sizes include 1/8", 1/4", 3/8", 1/2", 5/8", 3/4", 7/8", and 1 1/4".

2. Measure the Thread:
- Diameter: Use a caliper to measure the outer diameter of the male thread or the inner diameter of the female thread.
- Threads Per Inch (TPI): Use a thread pitch gauge to determine the number of threads per inch.

3. Reference JIC Size Chart: Match the measured values against a JIC thread size chart. For example:
- 1/4" OD with 20 TPI identifies a 1/4" JIC fitting.
- 7/8" OD with 14 TPI identifies a 7/8" JIC fitting.

4. Selecting the Fitting:
- Ensure the fitting has a 37° flare seat to seal correctly.
- Verify that the male and female parts match in both size and thread pitch.

5. Installing JIC Fittings:
- Clean the Threads: Remove any debris to avoid leaks.
- Lubricate: Apply light lubricant to the threads and seating surface.
- Tighten: Use suitable wrenches and tighten until the flare contacts and seals. Avoid over-tightening to prevent damage.

6. Testing for Leaks: After installing, pressurize the system and check for leaks. Use a specific hydraulic fluid to prevent seal damage.

Safety Note: Always follow manufacturer guidelines for torque specifications to ensure proper installation and avoid damage.

By understanding these steps, JIC thread sizes can be effectively used in hydraulic systems for secure and leak-proof connections.

"jic thread sizes" Comparative Analysis

JIC (Joint Industry Council) threads are widely used in hydraulic and other fluid power applications, known for their reliable connection and ease of assembly and disassembly. They follow the SAE J514 standard and typically come in three series of sizes: 37-degree flare (JIC), 45-degree flare, and NPT (National Pipe Tapered).

37-Degree Flare (JIC):

- Design: 37-degree angle, British Standard Pipe Parallel (BSPP) threads.
- Sizes: Range from 1/8 to 2 inches.
- Application: High-pressure systems.
- Advantages: Provides a metal-to-metal seal that is highly resistant to mechanical stress and vibration, ensuring a leak-proof connection.

45-Degree Flare:

- Design: 45-degree angle, typically used in automotive and refrigeration systems.
- Sizes: Also, range from 1/8 to 2 inches but less common in heavy machinery.
- Application: Lower pressure than 37-degree JIC.
- Advantages: Easier to assemble, suitable for systems not subject to high pressure or vibration.

NPT (National Pipe Tapered):

- Design: Tapered threads that require sealant.
- Sizes: Measured in nominal pipe size (NPS) from 1/16 to 2 inches.
- Application: Used in plumbing and piping systems.
- Advantages: Strong thread engagement, commonly available.

Comparative Analysis:

1. Pressure Handling: 37-degree JIC threads offer superior handling of high pressure and mechanical stress, making them ideal for demanding applications like hydraulic systems.
2. Ease of Assembly: The 45-degree flare is simpler to install but not suitable for high-stress conditions.
3. Versatility: NPT threads are versatile and commonly used in a variety of plumbing applications but require sealant for a proper seal, unlike JIC threads that have a built-in metal-to-metal seal.

Conclusion:

Selecting the appropriate JIC thread size and type depends on the specific application requirements, including pressure, mechanical stress, and ease of assembly. For high-pressure hydraulic systems, 37-degree JIC threads are the best choice. For simpler, low-pressure systems, the 45-degree flare may suffice. For general plumbing, NPT threads offer versatility but require careful sealing.

"jic thread sizes" Warranty and Support

Warranty and Support for JIC Thread Sizes

Our JIC (Joint Industry Council) threaded fittings are meticulously manufactured to achieve the highest standards of quality and reliability. We understand that our customers expect durability and performance, and we stand firmly behind our products with a comprehensive warranty and support service.

#### Warranty

We provide a one-year limited warranty on all JIC-threaded fittings from the date of purchase. This warranty covers defects in material and workmanship under normal use and maintenance. If any JIC fitting is found to be defective within the warranty period, we will repair or replace it at no cost to the customer.

However, please be aware that this warranty does not cover:
- Damage due to misuse, improper installation, or modifications.
- Products that have been subject to harsh environmental conditions beyond normal use.
- Wear and tear from regular usage.

To make a warranty claim, please contact our customer service team with proof of purchase and a detailed description of the defect. We may require the product to be returned for inspection.

#### Support

We are committed to providing exceptional support and customer service. Our team of experienced technicians is available to assist you with:
- Product selection: Ensuring you choose the right JIC thread size for your application.
- Installation guidance: Offering step-by-step instructions and best practices for a trouble-free installation.
- Troubleshooting: Assisting with any issues you may encounter to ensure optimal performance.

Our customer support can be reached via:
- Phone: [Customer Support Phone Number] - Email: [Customer Support Email] - Live Chat: Available on our website during business hours

We also offer a comprehensive online resource library, including technical datasheets, installation guides, and FAQs to help you find quick answers to common questions.

Your satisfaction is our priority. Thank you for choosing our JIC thread fittings—reliable performance and peace of mind come standard.

List "jic thread sizes" FAQ

JIC Thread Sizes FAQ

Q: What does JIC stand for?
A: JIC stands for Joint Industry Council. It's a standard for hydraulic fittings widely used in fluid power systems.

Q: What are common JIC thread sizes?
A: Typical sizes include:
- 1/8" JIC
- 3/16" JIC
- 1/4" JIC
- 5/16" JIC
- 3/8" JIC
- 1/2" JIC
- 5/8" JIC
- 3/4" JIC
- 7/8" JIC
- 1" JIC
- 1-1/4" JIC
- 1-1/2" JIC
- 2" JIC

Q: How are JIC thread sizes measured?
A: JIC thread sizes are defined by their outer diameter and threads per inch (TPI). Measurements are typically taken in inches.

Q: What is the angle for JIC threads?
A: JIC threads have a 37-degree flare seating surface, optimizing sealing capacity.

Q: Are JIC fittings interchangeable with other fitting types?
A: JIC fittings are often interchangeable with SAE 37-degree fittings but not compatible with 45-degree flare fittings or other types without adapters.

Q: Where are JIC fittings commonly used?
A: JIC fittings are prevalent in high-pressure hydraulic applications, including industrial machinery, automotive, and aerospace industries.

Q: How do I identify a JIC fitting?
A: Measure the outer diameter and count the threads per inch. Verify the 37-degree angle to distinguish from other flare fittings.

Q: Do JIC fittings support high-pressure applications?
A: Yes, JIC fittings are designed to handle high-pressure systems, making them suitable for rigorous environments.

Q: What materials are JIC fittings made from?
A: Common materials include stainless steel, brass, and carbon steel, ensuring durability and resistance to corrosion.

Q: How do I ensure a proper seal with JIC fittings?
A: Ensure the 37-degree flare is clean, undamaged, and properly aligned. Use a torque wrench to tighten fittings to the manufacturer's specifications.

Q: Are there specific tools for installing JIC fittings?
A: Yes, a torque wrench and proper flare nut wrenches are recommended for installation to ensure proper fitting and avoid over-tightening.

By understanding these key aspects, you'll be better equipped to work with JIC thread sizes and fittings efficiently.

Top 10 FAQ with answer about jic thread sizes for Buyer Sourcing from China

Certainly! Here are the top 10 frequently asked questions (FAQ) related to JIC thread sizes for buyer sourcing from China, with concise answers:

1. What is JIC thread?
- JIC (Joint Industry Council) is a type of thread standard used primarily in hydraulic and high-pressure applications. It features a 37-degree flare seating surface and is recognized for its leak-resistant properties.

2. How can I identify JIC threads?
- JIC threads are identified by measuring the outer diameter (OD) of the male thread or the inner diameter (ID) of the female thread and counting the threads per inch (TPI). They often follow the SAE J514 standard.

3. Why choose JIC threads for hydraulic applications?
- JIC threads are trusted for their robust sealing performance, easy assembly, and resistance to vibrations and high pressures, making them ideal for hydraulic systems.

4. What common materials are JIC fittings made of?
- JIC fittings are often made from materials such as stainless steel, carbon steel, and brass, chosen for their durability and corrosion resistance.

5. What are the standard sizes for JIC fittings?
- JIC fittings are available in standard sizes ranging from 1/8 inch to 2 inches, covering a variety of applications and pressure requirements.

6. How do I ensure quality when sourcing JIC fittings from China?
- Verify that the supplier follows international standards like SAE J514, request material certifications, and conduct third-party inspections to ensure quality.

7. What are some key considerations when selecting a JIC fitting supplier from China?
- Consider factors such as the supplier's experience, manufacturing capabilities, quality control processes, and ability to provide warranty and post-sale support.

8. Can I get custom JIC fittings made in China?
- Yes, many Chinese suppliers offer custom manufacturing services to meet specific requirements. Ensure detailed specifications are provided and agreed upon.

9. What are common applications of JIC fittings?
- JIC fittings are widely used in industries like agriculture, construction, automotive, and aerospace, particularly in hydraulic and fuel systems.

10. Is it possible to get samples before placing a bulk order?
- Most reputable suppliers in China are willing to provide samples for quality assessment before committing to a bulk order. Always negotiate sample availability and related costs upfront.

By addressing these FAQs, buyers can make informed decisions and establish fruitful sourcing relationships with Chinese suppliers for JIC thread sizes.