Carbon Steel Hex Flanged Slotted Nut

Core Features

Slotted Hexagon Design – The nut incorporates slots machined into the upper section of the hexagon body that align with cotter pin holes in the mating bolt. When a cotter pin is inserted through the slots and bolt hole, it physically prevents the nut from rotating and loosening.

Integrated Flange Base – The flange is formed as a single piece with the nut body, providing an enlarged bearing surface that distributes clamping force over a wider area compared to standard hex nuts.

Mechanical Locking Mechanism – The slotted configuration provides a positive mechanical locking method, in contrast to friction-based locking mechanisms that may lose effectiveness over time or under vibration.

Hexagon Drive Configuration – The standard hexagon profile allows installation and removal using conventional wrenches or sockets.

Product Characteristics

The fastener is produced with a hexagon body and a flanged base. The slots are machined into the top portion of the nut body at defined depths and widths, positioned to align with standard cotter pin hole locations on bolts. The slot width and depth are dimensioned to accommodate cotter pins of specified diameters while maintaining nut structural integrity.

The flange outside diameter and thickness are dimensioned to provide load distribution across the bearing surface. The flange underside is designed with a flat bearing surface that contacts the workpiece. Thread dimensions and tolerances follow standard metric thread profiles.

Material composition and heat treatment processes are regulated to meet the mechanical property requirements for specified performance grades. Carbon steel grades are available for general applications, with performance grades 8, 10, and 12 providing defined proof load and tensile strength ranges. Stainless steel grade A2-70 is available for corrosion-resistant requirements. Surface treatment options include zinc plating with various chromate finishes, zinc flake coating, nickel plating, and phosphate coating.

Application Scenarios

Vibration-Prone Assemblies – Used in equipment subject to vibration and cyclic loading where standard locking methods may be insufficient. The cotter pin provides positive mechanical locking that prevents loosening under dynamic conditions .

Automotive and Transportation – Applied in chassis components, suspension systems, and powertrain assemblies where the flange provides load distribution and the slotted configuration allows positive locking .

Heavy Equipment and Machinery – Employed in construction equipment, agricultural machinery, and industrial machinery where secure fastening is required and where the flange bearing surface provides load distribution .

Steel Structures and Infrastructure – Used in structural connections, pipe supports, and industrial brackets where vibration resistance is specified and the flange provides increased bearing surface .

Customization Options

Specifications and configurations can be adjusted based on application requirements. Material grades include carbon steel for general applications and stainless steel grades for corrosion-resistant requirements. Surface treatments are selectable according to environmental exposure conditions, including zinc plating with various chromate finishes, zinc flake coating, nickel plating, and phosphate coating. Strength grades can be matched to specific tensile and yield strength criteria defined in the application engineering specifications.

Frequently Asked Questions

Q: What is the difference between a slotted nut and a castle nut?
A: Slotted nuts and castle nuts are similar in function but have different configurations. Slotted nuts have slots cut across the top of the hexagon body, while castle nuts have raised cylindrical sections with slots between them. Both accommodate cotter pins for positive locking.

Q: How does the slotted locking mechanism work?
A: After the nut is tightened to the specified torque, a cotter pin is inserted through one of the slots in the nut and through the hole in the bolt. The pin is then bent to secure it in place, preventing the nut from rotating off the bolt even under vibration .

Q: What is the recommended tightening procedure for slotted nuts?
A: The nut should be tightened to the specified torque value, then advanced to align the nearest slot with the bolt hole. The nut should not be backed off to achieve alignment; it should be tightened forward to the next slot position. A cotter pin is then inserted and secured.

Q: Are these nuts reusable after removal?
A: The nut itself is reusable, provided the threads and slots remain in satisfactory condition. However, the cotter pin should be replaced with a new pin upon reassembly, as the pin may be damaged during removal.

Q: What thread sizes are available?
A: Thread sizes range from M4 to M36, with fine and coarse thread pitches available. Product grades are classified as Grade A for diameters up to 16mm and Grade B for diameters exceeding 16mm.

Q: What is the difference between this and standard flange nuts without slots?
A: The slotted configuration provides a positive mechanical locking method using a cotter pin, which physically prevents rotation. Standard flange nuts without slots rely on friction from the serrated flange or other means for locking.

Installation Considerations

The nut should be tightened to the specified torque using a torque wrench. After reaching the specified torque, continue tightening to align the nearest slot with the cotter pin hole in the bolt. The nut should not be loosened to achieve alignment; it must be advanced forward to the next slot position. A cotter pin of the specified diameter should be inserted through the slot and bolt hole, then bent to secure it in place.

Thread condition should be inspected before installation; damaged or contaminated threads may affect torque readings and assembly integrity. For plated or coated nuts, coating thickness should be within specified tolerances to maintain thread fit and slot dimensions. When used in high-vibration applications, the cotter pin should be inspected periodically to confirm it remains in place and properly secured.