A bore cut, also known as a plunge cut, is an advanced chainsaw technique where the tip of the guide bar is driven directly into the wood, creating a starting hole or a strategic internal cut, commonly used in tree felling to create a stable hinge.
Understanding the Bore Cut
What is a Bore Cut?
A bore cut involves driving the nose of the chainsaw bar straight into the wood. Unlike traditional cutting, which starts from an edge, a bore cut allows you to begin a cut from the middle of a log or tree. This technique is particularly useful for precision work, creating controlled hinges in felling, or releasing tension in wood.
Why Use a Bore Cut?
Bore cuts offer enhanced control and precision, making them invaluable for:
- Controlled Tree Felling: Creating a precise hinge for directional felling, significantly improving safety and accuracy.
- Relieving Wood Tension: Preventing the bar from pinching in logs under stress.
- Limbing: Safely removing large branches close to the trunk without damaging the main stem.
- Creating Openings: Making internal cuts or starting points in wood for various tasks.
Essential Safety Precautions for Bore Cutting
Performing a bore cut requires extreme caution due to the high risk of kickback, which occurs when the tip of the guide bar strikes an object or gets pinched, causing the saw to violently thrust backward and upward towards the operator.
Personal Protective Equipment (PPE)
Always wear appropriate PPE to minimize risks:
- Helmet: With a face shield for eye and face protection.
- Ear Protection: Muffs or plugs to guard against noise-induced hearing loss.
- Chainsaw Chaps: Made of ballistic nylon to protect legs from chain contact.
- Heavy-Duty Gloves: For grip and hand protection.
- Steel-Toed Boots: With good ankle support and non-slip soles.
Chainsaw Safety Features
Ensure your chainsaw is equipped with and you understand how to use its safety features:
- Chain Brake: For immediate chain stoppage.
- Anti-Kickback Chain and Guide Bar: Designed to reduce the likelihood of kickback.
Kickback Awareness
The bore cut inherently uses the kickback zone (the top quadrant of the bar tip). To mitigate this risk, never use the very tip of the bar for the initial plunge. Instead, engage the bottom edge of the bar just behind the tip. For more details on chainsaw safety, refer to resources like the OSHA Chainsaw Safety Guide.
Work Area Assessment
Before making any cut, thoroughly assess your surroundings:
- Clear the area of obstructions.
- Plan clear escape routes, especially when felling trees.
- Identify potential hazards such as overhead branches or unstable ground.
Step-by-Step Guide to Performing a Bore Cut
Executing a bore cut safely and effectively requires careful planning and a precise technique.
Preparation
- Inspect Chainsaw: Ensure your chainsaw is in excellent working condition. The chain must be sharp, properly tensioned, and the fuel and bar oil levels adequate.
- Plan the Cut: Clearly determine the entry point, depth, and intended direction of your cut. Visualize the entire process before starting.
- Assess the Tree: If felling, evaluate the tree's lean, overall health, and potential hazards. Pay attention to the sawdust color as you cut; a change in color can indicate internal rot, which significantly affects the tree's stability and felling strategy.
The Technique
- Grip and Stance: Maintain a firm two-hand grip on the chainsaw with your thumbs wrapped around the handles. Adopt a balanced, stable stance with your feet shoulder-width apart.
- Engage the Chain: Start the chainsaw and bring it to full throttle. It is crucial to operate the saw at full speed throughout the entire bore cut to prevent kickback and ensure a clean cut.
- Initial Contact (Avoid Kickback Zone): Position the chainsaw so that the bottom edge of the guide bar, just behind the tip, makes initial contact with the wood. Avoid touching the very tip of the bar to the wood at this stage.
- Plunge into the Wood: With the chain at full speed, smoothly and steadily drive the bottom of the bar into the wood. Apply consistent, controlled pressure. The saw will begin to "plunge" directly into the material.
- Pivoting and Extending: Once the bar tip is fully enclosed within the wood (often referred to as being "pocketed"), the risk of kickback is greatly reduced. From this position, you can safely pivot the saw or extend the cut in any desired direction, using the top or bottom of the bar to finish your cut. For felling, you might bore into the tree, then cut towards the "back side" to establish the hinge and guide the fall.
- Creating the Hinge: When using a bore cut for felling, this internal cut is instrumental in establishing a strong, directional hinge. Once the necessary cuts are established, including the bore and the final back cut, the tree should tip over as intended, guided by the hinge you've meticulously created.
- Completing the Cut: Once the bore cut is complete and the objective achieved, carefully withdraw the saw from the wood while maintaining full throttle.
Practical Tips for Bore Cutting Success
- Maintain Full Throttle: Always run your chainsaw at full throttle during a bore cut to ensure the chain's speed prevents kickback and allows for efficient cutting.
- Sharp Chain: A dull chain significantly increases the effort required and the risk of kickback. Keep your chain regularly sharpened.
- Understand Wood Tension: Before cutting, assess whether the wood is under compression or tension to avoid pinching the bar.
- Practice: Master the technique on smaller, non-critical pieces of wood before attempting complex cuts on valuable timber or trees.
- Observe Tree's Reaction: If you are felling, ensure the back side is properly established, and continuously watch for the tree's movement; it should tip over as planned once the bore cut and hinge are complete.
- Clear Escape Path: Always have a pre-planned and clear escape route when felling.
Bore Cut Applications
The versatility of the bore cut makes it a critical technique in various situations:
- Tree Felling: Primarily used for creating the directional hinge in a tree, ensuring it falls precisely where intended.
- Limbing: Allows for clean cuts of large limbs without binding or damaging the main trunk.
- Bucking: Useful for cutting logs under tension, creating an opening to prevent the bar from getting pinched.
- Specialty Cuts: Essential for creating openings in wooden structures or for artistic woodcutting.
Bore Cutting Do's and Don'ts
| Do's | Don'ts |
|---|---|
| Always wear full PPE | Never use the very tip of the bar for initial contact |
| Maintain full throttle | Don't force the cut |
| Keep chain sharp and tensioned | Avoid cutting alone or when fatigued |
| Plan your cuts and escape routes | Don't neglect tree assessment (e.g., for rot) |
| Practice on safe, small material | Don't stand directly behind the saw during plunge |
