If you’re noticing your circular saw blade isn’t cutting as smoothly as it once did, then you’re probably wondering when it’s time to replace it with a new one.
Knowing when it’s time to replace your circular saw blade isn’t an exact science, but you’ll generally get a hint when the saw starts to be more of a pain to use. Look for things like excessive burning and chipping, increased difficulty making accurate cuts, and more frequent kickback.
If you’ve noticed this with your saw, then it’s time to consider replacing or sharpening your old blade.
Let’s take a closer look at when you should replace a circular saw blade, how long a typical blade should last, and consider whether you should sharpen a dull blade or replace it.
How to Know When a Circular Saw Blade is Dull?
While circular saws don’t have an indicator light telling you your blade is dull if you pay attention to your saw’s performance you should start to notice when the blade begins to dull.
Cuts that were effortless before will require more effort to push through the material. You’ll probably notice more binding and chipping than usual as well.
Seeing and smelling burning when making cuts is another telltale sign. This is an indication that the blade is dulled and has to work excessively hard to power through the material.
If you’ve noticed any of the above, it’s a good idea to remove the blade from the saw and give it a visual inspection.
Use a flashlight to clearly illuminate the blade and look for the following:
- Examine the blade’s teeth and look for any that are chipped, missing, or broken. If you find any of these, then it’s time to replace the blade. A blade with chipped or missing teeth is hazardous as it’s more likely to cause kickback and further teeth breaking off.
- If you’re not sure how sharp the teeth ought to be, an easy way to check is by comparing your blade with a new one. Feel the sharpness of the teeth with the back of your fingernail, and then compare the sharp blade with the one you’re inspecting. If there is a significant difference, that’s a good indicator your old blade will need sharpening/replacing.
Another thing to consider is whether your blade is dull or merely dirty and gummed up from wood resin buildup. This can happen if you cut a lot of softwoods like pine which has a tendency to gum up your blade. If this is the case you can often improve the performance by giving the blade a thorough cleaning.
How Long Does a Circular Saw Blade Last?
Circular saw blades can last anywhere from a few months to a decade or more, it really depends on the type of blade, what you cut with them, and how often you use the blade.
There are two common blade types used for cutting wood: carbide-tipped and stainless steel.
- Carbide tipped blades are the most common type sold today, and feature carbide-tipped teeth attached to a hardened steel blade. They last significantly longer than stainless steel blades, often lasting for several years before needing replacement.
- Stainless steel blades were the most common type before the invention of carbide-tipped blades. They last significantly less time than carbide-tipped blades but are easier to sharpen on your own. These blades will only stay sharp for about a tenth as long as carbide-tipped blades.
Another consideration is what materials you use your blades with. Hardwoods have a tendency to wear out blades faster than softwoods, and if you cut through material with nails or screws embedded you’re bound to decrease the lifespan significantly.
Of course, how often you use a blade will have a major impact on its lifespan. If you’re a contractor and use your saw on a daily basis, you’re going to need to replace it more often than a DIYer who picks up their saw every other weekend.
Should you Sharpen, Clean, or Replace a Blade?
When you’ve got a dull blade, you basically have three options: clean it in hopes of getting it working properly, replace it with a new one, or sharpen it. Let’s briefly take a look at each of these options.
Cleaning the Blade
Cleaning a blade can potentially restore it from poor performance to working like new. You won’t really know though until you try though.
Cleaning a saw blade is fairly straightforward; all you need is a bucket, an old brush, some blade cleaning solution, and little elbow grease. It’s also significantly cheaper to clean a blade than buy a new one.
Replacing the Blade
If the blade is beyond the point where cleaning it is enough, then it’s time to replace it. A quality carbide-tipped blade can be had for $20 to $30, so replacing an old blade is cheap enough that your wallet won’t notice the hit much.
Sharpening the Blade
There’s also the option of sharpening a blade once it’s too dull to use.
Stainless steel blades are fairly easy to sharpen on your own with a hand file, so if you’re partial to repairing your own gear this is a good option. Carbide-tipped blades are more difficult to sharpen, so unless you have a diamond wheel you’ll probably want to get your blade professionally sharpened.
Blade sharpening typically costs between 25¢ and 50¢ a tooth. This works out to $10 to $20 per blade. So, for cheap blades, it’s generally cheaper to just replace them, but more expensive specialty blades can be worthwhile to sharpen.