Changing the blade on a rotary saw, like a circular saw, involves a few key steps focused on safety and correctly installing the new blade. The process typically requires disengaging the blade using a spindle lock and loosening an arbor nut.
Safe Blade Changing
Safety is paramount when changing a saw blade. Always ensure the saw is completely disconnected from the power source before you begin. This prevents accidental start-ups that could cause serious injury.
Step-by-Step Guide to Changing a Circular Saw Blade
While "rotary saw" is a broad term, the common type referenced for blade changes is often a circular saw. Here's how you typically change its blade:
- Disconnect Power: Unplug the saw from the electrical outlet. This is the most crucial safety step.
- Prepare the Saw: Place the saw on a stable surface with the blade guard retracted or secured to expose the blade. Some saws have a lever or button to hold the guard open.
- Locate the Spindle Lock: Find the spindle lock button or lever on your saw. This mechanism locks the saw's arbor (the shaft the blade mounts onto) so it doesn't spin while you loosen or tighten the nut.
- Engage the Spindle Lock: Press the spindle lock in while you turn the blade until you feel it engage. As mentioned in the referenced video clip, you'll know it's engaged because the blade won't turn freely anymore.
- Loosen the Arbor Nut: Use the wrench that came with your saw (or an appropriately sized wrench) to loosen the arbor nut. Note that on most saws, this nut has reverse threads, meaning you turn it clockwise to loosen it.
- Remove the Old Blade: Once the nut is loose, remove it and any washers. Carefully lift the old blade off the arbor. Pay attention to how the washers and nut were arranged.
- Clean if Necessary: This is a good time to clean any dust or debris from the arbor and the saw's housing.
- Install the New Blade: Place the new blade onto the arbor. Crucially, ensure the teeth are facing the correct direction. There's usually an arrow on the blade or the saw indicating the direction of rotation. The teeth should point towards the front of the saw (the direction of the cut).
- Replace Washers and Nut: Put the washer(s) back on the arbor, followed by the arbor nut.
- Tighten the Arbor Nut: While keeping the spindle lock engaged, tighten the arbor nut by turning it counter-clockwise (due to the reverse threads). Tighten it firmly, but do not overtighten, as this can damage the saw or make future blade changes difficult.
- Release the Spindle Lock: Let go of the spindle lock button/lever.
- Check Blade Rotation: Give the blade a gentle spin by hand (with the power still off) to ensure it rotates freely and is seated correctly.
- Reconnect Power: You can now plug the saw back in.
Essential Tools
Typically, you only need one tool to change a circular saw blade:
- Arbor Wrench: Most circular saws come with a specific wrench designed to fit the arbor nut.
Checking Blade Direction
Incorrect blade direction is a common error. Always double-check the rotation arrow on the blade and the saw before tightening the nut. A blade installed backward will not cut effectively and can be dangerous.
Changing the blade on a rotary saw, particularly a circular saw, is a routine maintenance task that is straightforward once you understand the steps and prioritize safety.
