Roller chains are essential power transmission components in a wide range of machinery. If you need to replace a chain, accurate identification is critical for finding the right fit and ensuring optimal performance. Here's a detailed guide:

1. Check for Markings

The Easiest Way: Almost all roller chains have their size and specifications stamped directly onto the outer link plates. Look for markings like:

  • ANSI Numbers: "40," "50," "60," etc. (American National Standards Institute)
  • ISO/BS Numbers: "06B," "08B," "10B," etc. (International Organization for Standardization/British Standard)
  • Conveyor Style: "C2080H", "81X", "C40", etc.

Cleaning for Visibility: Older chains may be covered in dirt or grease. A gentle cleaning with a degreaser and a wire brush should reveal any markings. Markings may not be on every plate, so check multiple link plates if markings aren't immediately visible.

2. Measure Your Old Chain (If No Markings)

Required Tools: A digital caliper is essential for accurate measurements. Avoid using rulers or tape measures.

Key Measurements:

roller chain points of measurement
  • Pitch: The distance between the centers of two consecutive pins. This is the primary determining factor for chain size.
  • Roller Diameter: The diameter of the chain's rollers.
  • Inner Width: The distance between the inner link plates.

Roller Chain Size Chart: Compare your measurements to a comprehensive roller chain size chart, available from manufacturers or online resources.

3. Additional Identification Tips

  • Simplex, Duplex, or Triplex: Determine the number of roller strands in your chain.
  • Special Features: Look for offset links, extended pins, or attachments.
  • Visual Comparison: If feasible, compare your old chain with a new one of known specifications.