Speed of a Bullet

Do you know what is meant by the phrase chain shot, when related to forestry operations?

  • Chain shot is the high velocity separation and ejection of a piece or pieces of cutting chain from the end of a broken chain in mechanised timber harvesting. Chain shot exposes both machine operators and bystanders to a risk of serious injury or death. Chain shot typically occurs near the drive end of the cutting system but can also come from the bar tip area.

Can chain shot and related injuries be eliminated from mechanised timber harvesting and processing?

No! Operators must always treat an operating chain and bar as if it was a loaded gun – always point it in a direction away from people.

The likelihood of a chain shot accident can be minimised through site planning, machine safeguarding, proper saw chain and guide bar maintenance and safe machine operations.


  • Do not operate a harvester with its chain shot eliminator missing.
  • A sprocket with only 0.6mm of wear will increase chain wear and therefore increase the risk of chain shot.
  • As a general rule, you should fit a new sprocket for every 10 chains.
  • Ensure chains are in good condition.
  • Ensure you use the correct chain lubrication.
  • Ensure your machine settings are correct. An over-speeding chain or excessive bar force increases your chances of chain shot.

During November, Tilhill’s Harvesting Managers will be undertaking a themed inspection regime on harvesting operations with regards to chain safety features.