Basic principles of chainsaw kickback.
What is chainsaw kickback? How do you prevent it?
Kickback is the unexpected reaction that causes the chainsaw bar to jump off an object toward you. Kickback can happen very suddenly. It is when the chainsaw either swings back or jumps back at the user. Even a stationary chain will cut flesh. It is essential to understand kickback, what causes it, and how to control it using the right techniques.
There are 2 types of kickback :
- Linear Kickback : A fast backward motion of the chainsaw results when the chain at the opposite end of the bar is pinched by the object being cut.
- Rotational Kickback : Occurs when the nose or tip of the guide bar touches an object causing the saw to be thrown back toward the user with great force and in an out of control manner, making for a very dangerous situation.
Before I discuss the mechanics of a kickback, I want to reflect on the forces you encounter when using a chainsaw. When in motion, the chain on top of the bar moves away from you, around the nose, and back to the chainsaw. When cutting with the top edge of the bar, the chainsaw is forced towards you by the teeth biting into the wood, pushing you back. At the bottom edge of the bar, the chain moves towards you. As the teeth bite into the wood, the chainsaw tends to move away from you.
At both top and bottom cutting edges, those forces are controllable. Many of the teeth are in contact with the wood, and you force the bar into the cut. The teeth are also operating at their designed cutting angles, making them effective cutters. It is the usual and safest way to use the chainsaw, but this position can also experience kickback.
VIDEO | See what Chainsaw Kickback looks like…
When cutting with any straight edge of the bar, kickback can happen when the opposite edge of the bar moves into the cut. While cutting with the bottom edge of the bar, a kickback can happen when the chain at the top is suddenly pinched. This happens when the wood closes in by sagging at the cut. It abruptly changes the pulling force into a pushing force and drives the chainsaw back at you. The change may upset your balance and put your legs in danger.
Rotational kickback force is the least controllable. It happens at the tip of the bar, often referred to as the kickback danger zone of the bar. At the nose, the cutting angles of the teeth as they move around the nose. Here, they are affected by the radius of the nose. The cutting edges angle back, causing them to become inefficient and will tend to run on the wood instead of cutting into it. The force created as the teeth run on the wood sends the tip of the bar rapidly upward, swinging it back towards you. This can force the chainsaw from your hand on the top bar, causing you to lose control of the chainsaw.
A bar with a smaller diameter nose reduces kickback and is called a low-kickback bar. The smaller diameter allows fewer teeth to make contact, making the kickback more controllable. Specialist carving bars are available with smaller pointed noses.
VIDEO | Understanding Chainsaw Safety Features, including kickback
Tips on How to Avoid Chainsaw Kickback
- Always keep a good grip on the chainsaw with both hands. The right hand should firmly grip the rear handle, with a firm hold on the front handle using the left hand.
- Before you start, make sure that the area in which you’re cutting is free from obstructions.
- Always watch the nose of the bar. Do not let the nose make contact with anything, like a log, branch, or any other obstruction.
- Always cut at high engine/motor speeds. The chain is most effective at high cutting rates, and less prone to kickback.
- Hold the chainsaw close to you and never cut above shoulder height.
- Not all chainsaw cutting chains are equal. Some are lighter than others and pitches vary to suit different chainsaw sizes and tasks. Special low kickback chains are available which reduce the risks. Always use the chain most suitable for your cutting requirements and experience.
- Be extremely cautious of limbs under tension that can recoil or close up on the bar.
- Work on the left side of the trunk, as close as possible to the chainsaw for maximum control.
- Be attentive and wide awake. Do not use a chainsaw if you feel ill, are intoxicated, or distracted.
- Small, light pieces can jam in the chain and be thrown toward you. This may cause you to lose control of the
- Never cut stacked logs or branches. Always separate them and cut one log or one piece at a time.
- Remove all cut pieces to ensure a firm footing and to keep your working area safe.
- Before you operate the chainsaw, always ensure that the chain brake system is working correctly.
- If all else fails, your safety clothing is there to protect you. Always wear your full safety kit and work safely.
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Everyone who uses a chainsaw should read this. (Buy from Amazon)
More Information | Chainsaw Kickback
For more information on chainsaw kickback, have a look at these resources below:
- How to safely operate a chainsaw (from Remington)
- Chainsaw Safety Features (Wikipedia)
- Chain Saw Kickback Explained: Learn How to Avoid The Danger (Oregon)
- Chainsaw Safety : Understanding Rotational Kickback (Tree Care Industry Association)
- STIHL Safety Manual (PDF document)
- Study : Kickback risk of portable chainsaws while cutting wood of different properties: laboratory tests and deductions
For a safer chainsaw…
Consider the WORX WG320. This eliminates all the dangers of kickback. If you only need to cut branches less than 4″ then this is an excellent alternative to a conventional chainsaw. Read our review.
Weighs 7.9 lbs. making it easy to use without tiring. (Buy from Amazon)