This 3/8" x 20 BSF Chrome Button Die is designed for forming, repairing, and restoring British Standard Fine (BSF) external threads. Its fine-pitch profile provides strong thread engagement and improved resistance to stripping, making it suitable for precision mechanical applications and classic machinery maintenance.

Key Features:

• Thread Standard: British Standard Fine (BSF), featuring a finer pitch than the British Standard Whitworth (BSW) system.
• Versatile Use:
  • Ideal for chasing, restoring, and cleaning worn or damaged threads.
  • Suitable for cutting new male threads on non-ferrous metals and plastics.
• Material: Durable chrome alloy for general-purpose thread cutting (not recommended for precision, structural, or safety-critical applications).
• Thread Form Details:
  • BSF was first introduced in 1908 and later standardised under BS84:1956.
  • Fine-pitch threads provide greater tensile stress area compared to coarse series threads.
  • Improved resistance to stripping under high load conditions.
  • Ideal when thread engagement length is limited or when used in thin-walled components.

Technical Specifications:

• Diameter (inch): 3/8
• Pitch (TPI): 20
• Thread Form: BSF
• Outside Diameter: 1"

Applications:

BSF button dies are commonly used in restoration work, general engineering, automotive repair, agricultural machinery, and applications where fine threads are preferred for strength and engagement efficiency.