“I was just looking at a few chainsaws and I noticed a weird, kind of curved handle thingy on the top of it. It moved back and forth with a click. What in the world is that thing and what does it do?”
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It’s called a chain brake and it’s a safety feature of most (if not all) chainsaws manufactured these days.
How’s it all work?
Inside of your chainsaw is an engine and when the engine is running, it turns a little shaft which engages with a little metal wheel called a drum. The drum connects to the chain on the chainsaw bar and when drum is turning, the blade is moving. The blade goes round and round and the cutting begins.
The chain brake is exactly what it sounds like. It stops the blade from turning by tightening a metal band around the drum. If the drum can’t turn, the blade doesn’t move. If it is working properly, the chain will not turn when the chain brake is engaged and most chainsaws will not start if the chain brake is engaged as well
So, why do I need this? One word: Kickback!
Sometimes, when you’re cutting wood, the tip of the bar can encounter a dense spot; something hard or difficult for the chain to cut through, or perhaps the bar may become pinched between two moving pieces of wood.
Cutting horizontally into a tree trunk, or cutting vertically into a suspended piece of lumber can cause this. The bar is suddenly held fast by the compressing wood, resulting again in the kickback reaction.
When this happens, the bar can rise suddenly upwards or “kick back”. A reaction wherein the chain is driven even harder into the wood. When this occurs, the jolt can force the bar to hurl the bar upwards towards the operator. This unexpected reaction can cause very severe injury or death. The true hazard of kickback is that it occurs with no warning and often so quickly that there is time for evasive action.
It does what?
The chain brake is designed to connect with the wood as the bar is yanked forward. The wood pushes the chain brake towards the operator, engaging the brake band and stopping the operation before injury occurs.
It’s a safety feature that is often overlooked and under-appreciated, but it’s essential for safer operations.
So put the brakes on kickback and use your saw safely!
If you have any questions or comments please feel free to contact us via phone, email or the comments section below.