eli5 How woodcutting tablesaws can cut through wood with no issue, but when other material, like your finger, gets in the way of the saw, it shuts down immediately

Question

eli5 How woodcutting tablesaws can cut through wood with no issue, but when other material, like your finger, gets in the way of the saw, it shuts down immediately

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Answer 1

It’s very important to note right up front that **only saws with this safety system installed will do this.** Other saws will happily cut your fingers off.

That said: it’s a safety system installed on some saws. An electrical current runs through the blade, and when it touches your finger the safety system detects the change. This causes a device below the saw to forcefully grab the blade and make it stop rotating, often with enough force to damage the blade.

Wood doesn’t cause this electrical change, so the system doesn’t activate.