We’ve all been there before: you’re ready to get to work, you check the teeth of your saw, and you quickly realize it’s about as sharp as a marble. Sure, you could power through the job, but at what cost? You’re inevitably going to be dealing with messy cuts and tearout. The worst part is you’re putting yourself in danger.
Today, we’re going to cover everything you need to know about saw blade sharpening, so you can keep your blades in top notch shape while also saving yourself some money along the way.
What You Can and Can’t Sharpen
While most saw blades can be sharpened with little more than some time and effort, certain blades don’t fit the bill, and identifying them now will help you save time later.
Blades with steel teeth can be easily sharpened at home, provided you’re dealing with a quality blade. If you’re working with an exceptionally cheap saw or blade, it’s probably best to cut your losses and pick up a new one. But, the average steel-toothed blade can be sharpened right in your workshop.
Carbide-tipped blades can also be sharpened. However, this is something you’ll need to seek professional help for, or you run the risk of removing the remaining carbide from the teeth, which will compromise the integrity of the blade.
For carbide blades, head over to google and find a shop in your area that offers saw blade sharpening. Or, if you’re old-school, crack open the phonebook. These shops usually charge between 25 and 50 cents per tooth.
Of course, you could attempt sharpening these blades yourself, provided you have a diamond wheel sharpener. But beware, one wrong move and you can easily round off the edge of the blade, ruining it forever.
If you’re dealing with a blade that can’t be sharpened, it’s still worth stashing away in a drawer in your workshop. These old blades are just what the doctor ordered for demolition work, or cutting through old lumber that may have hidden nails or screws. In other words – these old blades let you save your good blades for other work where precision is more important.
Sharpening Circular Saw Blades
Sharpening circular saw blades is a reasonably straightforward undertaking; all you’ll need to get it done is patience and a few tools. Here’s what you’ll need:
- Diamond file
- Oven cleaner, or a specialized saw blade cleaner
- Bench vise
- Shop rag
- A wrench (provided you don’t have tool-free blade removal on your saw)
Step 1: Remove the Saw Blade
Once you’re ready to get started, you’ll remove the blade from your saw. Each saw is different, so you’ll need to refer to your owner’s manual if you’ve never removed the blade before. Most saws feature a button or switch that locks the arbor in place, allowing you to quickly remove the blade, or remove the bolt that secures the blade in the saw.
Keep in mind that even though you’re dealing with a dull blade, it’s still a saw blade. Place a shop rag over the teeth to keep your hand out of harm’s way while working on the blade.
Step 2: Preparing the Blade for Sharpening
If you’re dealing with a dull blade, that means that you’ve already gotten plenty of use out of that blade. Chances are, it’s caked with sap and grime from all the cutting, and you’ll want to remove all that gunk before you begin sharpening the blade.
Every craftsman has their preferred method for this. We like to use oven cleaner, as it produces the best results. But, it’s caustic and dangerous to the environment, which has prompted many to search for greener alternatives. Whatever you decide to use, check out our saw blade sharpening guide for more details.
With the blade cleaned, it’s time to transfer it to your bench vise for sharpening. Overtightening your blade in the vise can cause warping, so it’s critical you don’t overtighten the blade in the vise. To prevent this, we just take the shop rag we used in step one and place it on each side of the blade as we tighten the blade in the vise.
Step 3: Mark the Blade
This step is the easiest to overlook, but arguably the most critical. Marking the blade with a shop pencil or Sharpie will let you know when you’ve reached the end of the blade, so you don’t risk oversharpening it. Once you’ve sharpened the whole blade and you arrive back at your mark, you’ll know your work is done.
Step 4: File the Blade
Keep in mind that every other tooth on the blade has a bevel which you’ll need to account for as you sharpen. To do this, you’re going to skip every other tooth as you sharpen.
Starting with the tooth that you’ve marked as your starting point, locate the bevel of the blade. Hold your file at a 20-degree angle to the bevel, and give it 3-4 even strokes with your file, along the full length of the tooth.
Repeat this process with every other tooth until you’ve arrived back at your mark.
Step 5: Flip and Repeat
Once you’ve sharpened the first side of the blade, flip the blade in your bench vise and repeat the process starting at step 3. Remark the blade, so you’ll know where your starting point is, and sharpen each beveled tooth on the blade the same way you did in step 4. Once you’ve arrived back at your second mark, you’ll know your blade is fully sharpened and ready to go.
Step 6: Return the Blade to the Saw
Once you’re done admiring your great work, you can remove the blade from the vise and reinstall it in your saw. Follow the directions for your saw to ensure the blade is seated correctly in the housing. Your new old saw blade is now ready for use!
Sharpening Hand Saw Blades
Just as you can sharpen circular saw blades, you can also sharpen your hand saws as well. The process and tools you’ll need are a bit different.
- Oven cleaner or the saw cleaner of your choice
- Saw set pliers
- Rake guide
- Bench vise
- Diamond file
- India stone or #600 diamond file
Step 1: Clean the Saw
Before getting started, we’re going to remove any sap and grime from the blade of the saw, just as we did in the circular saw section above.
Step 2: Setting the Saw
Depending on your saw’s condition, this step may not be necessary. A saw should be set if it’s binding in a cut regularly. If the saw is loose in the kerf following a cut, then the blade is overset, and we’ll fix that in the final step.
Clamp the blade into your vise so that about 2” of the blade and teeth are above the vise. Examine the set of each tooth to see if it needs to be adjusted. If you find any teeth that are set too far away from you, clamp your saw set pliers over that tooth, and bend it slightly back towards the saw.
Step 3: Jointing the Blade
Jointing a saw blade ensures that each tooth is the same height as the tooth before it. This will help you achieve consistency in your cuts.
With the blade still clamped in the vise, hold your file with one hand on the handle and the other hand on the tip of the file, and run your file across the full length of the saw, applying gentle pressure.
Next, repeat this process with a rake guide attached to your file to set the tooth rake. Most rip saws have a tooth rake of 5-10 degrees while crosscut saws typically are set at 15 degrees. This will ensure consistent geometry across every tooth in the saw.
Step 4: Sharpen Each Tooth
Once your blade is joined, you can move on to sharpening each tooth. With your blade still clamped in the vise, place your file in the gullet of the sawtooth closest to the heel. With the file perpendicular to the side of the saw blade, apply gentle pressure and run the entire file across the blade.
As you file, look at the flat to the right of the tooth you’re filing. As soon as that flat disappears, you’re ready to move on to the next tooth.
Step 5: Stone the Saw
With your blade fully sharpened, it’s time to stone the saw, also known as side jointing.
Place the saw blade on your workbench so that the blade is flat against the bench with the handle hanging over the side. With an India stone of #600 grit diamond stone, run the stone across the full length of the blade.
One pass should do the trick, but if you identified that your saw was over-set in step 2, more passes might be necessary. Keep in mind that even severe over-sets can usually be corrected in three or four passes with the file, so don’t go crazy.
Conclusion
Learning how to sharpen saw blades is a critical skill that will help you save money on blades while you produce cleaner work at the same time. Blade sharpening is a labor of love, and it takes skill and patience to master. But, with a little practice, you should be well on your way to sharpening all your dull blades.
