The blade of a pruning saw will become dull over time and make the job you are using it for vastly more difficult and time consuming. By sharpening the blade, not only will you make the work go faster, but the cleaner cut will help the tree limbs heal faster. If you properly sharpen your saw regularly, you should never have to take more than about 10 or 15 minutes to complete this task, and you’ll never have to fight with a dull blade.
WARNING: Sharpening saw blades can be dangerous. Practice using the sharpening tools beforehand and always wear work gloves while sharpening.
Step 1 - Clean the Saw
Prior to handling the saw blade at all, make sure you put on thick work gloves. Even a dull blade is sharp, so in order to stay safe, it’s important that you cover your skin.
Before sharpening, you will need to make sure the saw is clean. Use a stiff brush, like steel, and soapy water or a foaming bathroom cleanser. Get between each tooth to dislodge any dirt and debris there. If there is sap on the saw, you can use kerosene to clean it off. Wet a cloth with some of the kerosene and dab it onto the spots of sap until they’re gone.
Step 2 - File the Teeth
The teeth of a pruning saw are very unusual so they actually require a special type of file to sharpen. You will want a Cant file, or any other type with a triangular cross section. It’s usually best to just go ahead and buy one when you’re purchasing the pruning saw so you don’t have to worry about it later. After all, if you own the saw, you will need it eventually.
Clamp your saw to a firm surface or slip it into a vise and make sure it has a good hold. Then, take your file and, starting from the rear of the saw and working toward the tip, sharpen the edges of the teeth pointing away from you one-by-one; this will be every other tooth in the sequence. You should hold your file at about a 30 degree angle to the saw while sharpening. Keep adjusting the blade in the clamps or vise so that you don’t work on any area that isn’t tightly secured, as this could cause teeth to chip. Also make sure that you give each tooth the same number of strokes as you go: eight strokes will work for a regular touch-up, 15 will made a mildly dull saw sharp, and 20 should suffice for a very dull saw.
When you reach the tip, unclamp your blade, turn it around, clamp it again, and repeat this process on the sharp edges of the rest of the teeth. Clean your pruning saw once more after you finish, and rub it with a light coat of oil before you store it.
Make sharpening part of your regular chores if you use this tool often and it will become a very quick and easy task.