Slotted Chicago Screws

Cold heading process is one of the new processes for pressure machining of less or no cutting
metal. It is a processing method that utilizes the plastic deformation of metal under the action of
external forces, and with the aid of molds, redistributes and transfers the volume of metal to form
the required parts or blanks. The cold heading process is most suitable for producing standard
fasteners such as bolts, screws, nuts, rivets, and pins.etc

1. Fundamental Definition

Slotted Chicago screws (commonly called sex bolts or binding barrels) are specialized two-piece fasteners designed for secure, flush-mounted assemblies. These mechanical fasteners consist of two interlocking components:

• Male screw: Features a slotted drive head and external machine threads

• Female barrel: Contains internal threads and an external flange for load distribution

2. Key Characteristics

• Reversible Assembly: Allows repeated disassembly without material damage

• Flush Mount Capability: Countersunk heads sit nearly flush with surfaces

• Vibration Resistance: Threaded connection resists self-loosening

• Material-Friendly: Eliminates compression damage common with rivets

4. Mechanical Properties

• Tensile Strength: 45,000-70,000 psi (carbon steel)

• Shear Strength: ~60% of tensile strength

• Torque Capacity: 4-25 in-lbs depending on size

• Temperature Range: -20°F to +250°F (untreated steel)

5. Functional Advantages

• Precision Tension Control: Adjustable tightness

• Clean Aesthetics: Low-profile installation

• Material Versatility: Compatible with leather, wood, plastics, composites

• Serviceability: Facilitates maintenance access

6. Industry Applications

• Leathercraft: Holsters, belts, saddles

• Woodworking: Furniture, cabinets, displays

• Industrial: Equipment panels, signage

• Commercial: Retail displays, sample cases

8. Quality Indicators

• Threads: Smooth engagement without cross-threading

• Flange: Flat bearing surface without burrs

• Slot: Centered, properly machined for driver engagement

10. Maintenance Considerations

• Inspection: Annual check in high-vibration use

• Replacement: When threads show >30% wear

• Corrosion Prevention: Use plated/stainless versions in humid environments

12. Historical Context

First patented in the late 19th century for bookbinding applications, Slotted Chicago Screws have evolved into essential fasteners across multiple industries. Their simple yet effective design has remained largely unchanged for over 100 years, demonstrating exceptional functional longevity.