Every home renovator or DIYer needs a circular saw and circular saw blades in their arsenal. Why?
- Make multiple kinds of cuts
- Can cut through many different materials (not just wood!)
- Are portable
- Are easy to use
While a circular saw can last a long time, the blades tend to wear down over time with use. What happens when the blade gets too dull? And why is it good to learn how to change and sharpen your circular saw blade? Read on and be a seasoned saw slinger that knows exactly how to change and sharpen circular saw blades.
When to change or sharpen your saw blade
If your blade becomes dull, it causes problems completing your projects. A dull saw blade can burn wood, causes you to use more force while cutting, and makes it difficult to follow a cut line.
A dull blade can be remedied in two ways. Changing the old saw blade for a new one or sharpening your current saw blade. Some opt for changing the blade entirely because sharpening a circular saw blade requires some extra work.
Dedicated and frugal DIYers need special sharpening tools to sharpen their own blades for continued use. This could pay off in the long run if you find you are buying multiple expensive blades all the time.
How do I change a circular saw blade?
Check your circular saw’s manual before attempting to change the blade. Each one is different and could have slightly different procedures.
Uninstalling a circular saw blade
1. Make sure the circular saw is turned off
The circular saw needs to be switched off and unplugged. If it has a battery cartridge, remove it.
2. Press down the shaft (or spindle) lock
The shaft (or spindle) lock is what keeps the circular saw blade from rotating freely. Press it down firmly and test to make sure the blade is not rotating. If there is no shaft or spindle lock, press the saw down on a scrap piece of wood to keep it in place while doing the next step.
3. Use a wrench to loosen the bolt
Follow your saw’s instructions on what tool to use to loosen the bolt. On the Makita Cordless Circular Saw, the hex wrench for the center bolt is stored directly on the saw right next to the battery pack.
If the blade is on the left of the saw, loosen the bolt in a clockwise direction. Loosen counterclockwise if the blade is on the right.
4. Remove the bolt, outer flange (or washer) and the blade
You want to make sure you install the blade exactly how you removed it, so remember which flange was on the inside and which was on the outside.
5. Clean the blade and all surrounding parts
Clean your saw blade and blade guards when you are changing the saw blade. This easy-to-do maintenance will ensure your saw and blade will last a long time.
To clean, simply dampen a washcloth or paper towel and wipe everything down. If there are tough spots, use a mild, citrus-based cleaner. You can also use an air can blast sawdust out of tight spots in your circular saw.
Installing (or reinstalling) a circular saw blade
Installing a circular saw blade is basically the reverse order of uninstalling it.
Do you notice arrows on the saw blade shaft and the saw blade? Make sure they match up. The direction of the teeth on the blade should be facing up.
Once the saw blade is in place, securely tighten the bolt.
How do I sharpen a circular saw blade?
There are four ways to sharpen a circular saw blade: sharpen by hand with a file, sharpen with a homemade sharpening jig, buy a sharpener (100+ USD), or take it to a shop to have it sharpened by a professional.
If you are sharpening by hand with a file, you can leave the blade in the saw if you want (make sure the saw has no power first). Otherwise, uninstall the circular saw blade first. If the blade is dirty, clean all the grease, tar, or debris off before sharpening. After that, follow these steps:
1. Mark the blade or tooth edge
Marking the edge of the teeth all the way around the saw blade helps you track your filing progress. This will keep you from filing the edges too much. You can also mark the tooth you started on so you know which tooth you started filing to avoid sharpening more than once.
2. Work your way around the blade, tooth by tooth
If you are hand-filling, place the file directly on the first tooth and stroke back and forth one time. Move on to the next tooth. If you are using the angle grinder, a couple of taps on the diamond sharpening disk will do (watch this video for help).
Now you have a newly sharpened circular saw blade ready for any job.