3903834
Twelve Point Cap Screw
Cummins®

The Twelve Point Cap Screw, Part #3903834, manufactured by Cummins, is a specialized fastener designed for use in commercial truck applications. This component is integral to ensuring the reliable performance of trucks by securely fastening various parts and assemblies. Its design and construction are tailored to meet the demanding requirements of heavy-duty applications, providing a robust solution for critical fastening needs ¹.

Basic Concepts of Twelve Point Cap Screws

A twelve point cap screw is a type of fastener that features twelve sides instead of the six found on standard hex cap screws. This design offers several advantages, including improved torque application and enhanced resistance to cam-out. The mechanics of a twelve point cap screw allow for more precise and consistent torque application, reducing the likelihood of over-tightening or stripping. Additionally, the increased number of contact points provides better engagement with the wrench, minimizing the risk of the wrench slipping off the screw head during installation or removal ².

Role in Truck Operation

This Cummins part plays a significant role in the operation of commercial trucks. It is commonly used in various applications, such as securing engine components, chassis assembly, and other critical areas where reliable fastening is required. By providing a secure and durable connection, this cap screw helps maintain the integrity and performance of the truck’s components under demanding conditions ³.

Key Features

The 3903834 Twelve Point Cap Screw is designed with several key features that enhance its performance and durability. These include a robust material composition, precise thread pitch, and special coatings or treatments that improve resistance to corrosion and wear. The material used in its construction is selected for its strength and durability, ensuring it can withstand the rigors of heavy-duty truck applications. The thread pitch is optimized for secure fastening, while any special coatings or treatments further enhance its performance in harsh operating environments.

Benefits

Using a twelve point cap screw in truck applications offers several benefits. These include improved torque application, reduced risk of stripping, enhanced security against loosening, and increased durability in harsh operating conditions. The design of the twelve point cap screw allows for more efficient and consistent torque application, minimizing the risk of damage to the fastener or the components being fastened. Additionally, the increased number of contact points provides better resistance to loosening, ensuring a secure connection over time. The durable construction and special coatings or treatments further enhance the screw’s performance and longevity in demanding environments.

Troubleshooting and Maintenance

Common issues that may arise with twelve point cap screws include stripping, loosening, and corrosion. To address these issues, it is important to follow proper installation and maintenance procedures. This includes using the correct torque settings to avoid over-tightening, regularly inspecting the screws for signs of wear or damage, and applying appropriate coatings or treatments to protect against corrosion. Proper maintenance ensures the longevity and reliable performance of the 3903834 Twelve Point Cap Screw, contributing to the overall reliability of the truck.

About Cummins

Cummins Inc. is a global power leader that designs, manufactures, and distributes diesel and natural gas engines, as well as related technologies. With a history of innovation and a commitment to quality, Cummins has established itself as a trusted provider of diesel engines and components for the commercial truck industry. The company’s expertise in engine manufacturing and its dedication to advancing technology ensure that its products, including the 3903834 Twelve Point Cap Screw, meet the highest standards of performance and reliability.

Compatibility with Cummins Engines

This part is a critical component in the assembly and maintenance of various Cummins engines. This screw is designed to provide secure fastening in applications where high strength and durability are required. Below is a detailed overview of its compatibility with different Cummins engine models.

B Series Engines

• B3.9, B4.5, B4.5 CM2350 B129B, B4.5 RGT, B5.6 CM2670 B152B, B5.9, B5.9 CM2670 B166C, B5.9 GAS PLUS CM556, B6.7, B6.7 CM2350 B135B, B6.7 CM2670 B153B, B6.7 CM2670 B164C, B6.7 G CMOH6.0 B125, B6.7S

This screw is extensively used across the B series engines. It is often employed in securing various engine components, ensuring that parts remain tightly fastened under operational stresses. This screw is particularly useful in applications where vibration and torque are significant factors.

F Series Engines

• F2.8 CM2620 F135B, F3.8 CM2350 F120B, F3.8 CM2350 F128C, F3.8 CM2620 F137B, F3.8 F102, F4.5 CM2620 F139B, F4.5 CM2620 F141C

In the F series engines, the 3903834 screw is utilized for fastening critical components that are subject to high operational loads. Its twelve-point design ensures a better grip and distribution of force, which is essential for maintaining the integrity of engine assemblies.

G Series Engines

• G5.9

The G series engine, specifically the G5.9, also benefits from the use of the 3903834 screw. This part is used in securing various engine mounts and brackets, ensuring that these components remain firmly in place under the dynamic conditions of engine operation.

D Series Engines

• D4.0 CM2620 D103B

The D4.0 CM2620 D103B engine incorporates the 3903834 screw in its design, particularly in areas where robust fastening is necessary to withstand the rigors of heavy-duty operations.

Application Considerations

When using the Twelve Point Cap Screw 3903834 in Cummins engines, it is crucial to adhere to the manufacturer’s specifications regarding torque settings and material compatibility. Proper installation and maintenance of this screw are essential for ensuring the longevity and performance of the engine components it secures.

Role of Part 3903834 Twelve Point Cap Screw in Engine Systems

This part is instrumental in securing various components within engine systems, ensuring stability and proper function. In the Air Compressor Upfit Kit, this cap screw is used to fasten the attachment securely to the starting motor mounting, which is vital for the efficient operation of the air compressor.

Within the Cylinder Block assembly, the Twelve Point Cap Screw plays a significant role in attaching the block to the flywheel. This secure attachment is essential for maintaining the structural integrity of the engine during operation.

For the Fuel Pump and Fuel Pump Body, the cap screw is employed in the mounting process, ensuring that the fuel pump is correctly positioned and operates without vibrations that could affect fuel delivery.

In the context of Engine Installation Kits, the Twelve Point Cap Screw is utilized in multiple applications. It secures the auxiliary pump to the cylinder block, ensuring a stable and leak-free connection. Additionally, it is crucial in the starter motor mounting, where it attaches the starting motor to the engine block, facilitating reliable engine starts.

The XPI JV Components and XPI JV System Cummins HD also benefit from the use of this cap screw. It is integral in the plumbing and mounting of various components, ensuring that the high-pressure injection system functions correctly.

Overall, the part 3903834 Twelve Point Cap Screw is a versatile fastener that contributes to the secure and efficient operation of numerous engine components.

Conclusion

The 3903834 Twelve Point Cap Screw is a critical component in the reliable operation of commercial trucks and Cummins engines. Its unique design, robust construction, and compatibility with various engine models make it an indispensable fastener in heavy-duty applications. Proper installation and maintenance of this screw ensure the longevity and performance of the components it secures, contributing to the overall reliability of the vehicle.