Updated: December 2018
Learning how to sharpen garden tools may be one of the most important things you can do to make your work in the garden easier and more enjoyable.
Why? Because a sharp tool cuts more easily and accurately than a dull one!
Sure, you can get away with using a dull tool (many people do), but a sharp tool will help you get done faster and enjoy your work more along the way.
In this article, I’ll show you how to sharpen garden tools such as weeding hoes and spades with a simple sharpening file.
No grinders, water stones, or jigs are necessary: just you, a tool and a file.
Intimidated? You’re not alone!
One last thought before we begin: If you’ve ever been intimidated by the thought of sharpening a tool, rest assured, you’re not alone. I used to be and know many gardeners who are, too.
If you’ve never done it, it’s natural to be hesitant, especially if you have a nice tool that you don’t want to mess up. Luckily, you’re not likely to do any lasting damage when sharpening with a file, and what’s more, you don’t need to create a razor sharp edge to have success. A decent edge will do.
That said, learning how to sharpen simple garden tools is a great starting place and can prepare you to sharpen more difficult tools such as pruners, axes and knives.
Prefer to learn from a video?
1. Select the Proper File
Sharpening files come in a variety of grades and lengths. Commonly available grades include bastard (coarse), second cut (medium) and smooth cut (fine). You may also be presented with both single and double cut files.
Single cut files have cutting teeth that run in only one direction. Double cut files have teeth that cross each other creating a diamond pattern.
Double cut files remove metal very quickly and leave a rough cutting edge; they are best suited to repairing damaged or very dull blades. In most circumstances a single cut file will be your best choice.
For sharpening garden tools, I suggest using a single cut file that is 8-12 inches in length, with either bastard or second cut coarseness.
A bastard file will cut faster, but I have come to like the smoother edge left by a second cut file.
If you want to repair damaged tools by hand, add a double cut file to your kit. It will save you much time and effort.
We offer some nice sharpening files here, but they are also readily available in hardware stores. Purchase a handle if the file does not already have one.
2. Clean Your Tool
If your tool head is dirty or greasy, give it a rinse before sharpening. Dirt, oil and sap will just clog your file and make more work.
Rubbing alcohol will remove any grease or sap, and be sure to wipe the head dry if you used water for cleaning.
Light surface rust will file off easily, but you may want to remove any thick rust with a wire brush or sandpaper to save your file.
A tool with heavy rust can be soaked in white vinegar overnight. The rust will loosen and wipe off easily with a rag.
3. Secure Your Tool
If possible, it is helpful to secure the tool-to-be-sharpened in some way. A bench vise works very well, but many tools can also be secured to a stable surface with clamps.
A good working height for the tool is about even with the elbow when your arm is bent.
With your tool held in place, you’ll have both hands free to guide the file. This will afford you more strength, control and precision.
If you can’t secure the tool in any way (perhaps while out in the garden), you’ll need to keep one hand on the tool and the other on the file. While less than ideal, it is certainly doable.
For long handled tools, place the end of the tool handle on the ground (tool head up) and using strong, even pressure, push down on the head while sharpening.
Short handled tools can be held under one knee with the tool head resting over your opposite thigh.
The idea is to minimize unwanted movement of the tool as much as possible.
4. The Sharpening Stroke
Now for the fun part.
Find a good, solid stance: knees slightly bent, feet somewhere between hip and shoulder width apart. You might try putting your left foot slightly more forward than your right (opposite if you’re a lefty). The more solid and balanced you are, the better your results will be.
Rest the tip of the file on the left side of the cutting edge of the tool. Take a look at the bevel angle of the blade and tilt your file up or down to match the angle. It doesn’t have to be exact and can be fine-tuned later.
Now, with slight downward pressure, push the file both up and across the cutting edge to the right (if you’re a lefty you’ll be pushing across to the left). Your second hand should rest on the top end of the file, where it helps maintain your angle and keep downward pressure even.
Try to keep your wrists and elbows fixed and move from the shoulders and hips. This will give a more consistent result.
Push forward and across until you get near the bottom (or heel) of the file. If you’re a beginner, it’s not a bad idea to wear a glove on your dominant hand to protect against an unintentional slip. Remember, you’re pushing toward a cutting edge!
If the blade you’re sharpening is short, one stroke may be all you need to reach the right side of the cutting edge. Most tools, however will require that you make multiple, overlapping strokes to sharpen the full length of the blade.
After your first stroke, lift the file and either return it to its starting position or place it slightly to the left of where you finished the stroke
Do not file in a back and forth motion, this will dull your file prematurely. File only in one direction, in this case the push stroke.
Continue this diagonal motion until you reach the other side of the blade.
You may need to make a 2nd pass before you really start to see and feel results. When the file is cutting, you will feel resistance, that’s a good sign. You don’t need to push down hard, just enough to get the file to bite. After one or two passes, you should be able to see the shiny new metal that you are exposing.
5. Assess Your Angle
Now is the time to assess your angle. Set aside your file and look at the blade with some good back light. A bevel gauge (shown above) is nice but by no means necessary.
Most of the time, the angle that arrives from the manufacturer is just fine, and all you need to do is follow it. In this case, the shiny new metal should match the original bevel.
If, for example, you can see new metal at the top of the bevel but not down by the cutting edge, you’ll need to either drop your hand slightly when filing or simply continue sharpening at that angle until you reach the actual cutting edge.
If the opposite is true, and you’re seeing new metal at the cutting edge but not at the top of the bevel, you’ll need to raise your hand slightly when filing.
A bevel angle of around 35 degrees is a good all-around angle for soil-working tools. It’s fairly thick, but that makes the edge stronger and less likely to chip or roll.
Once you’ve determined your angle, keep filing until you can see shiny new metal all the way down to the cutting edge.
6. When are You Done?
Continue filing until you can feel a burr on the backside of the cutting edge. A burr, also called a wire edge, is a small fold of metal that forms on the opposite side of the edge you are filing. You can feel it by running your fingers in a sort-of “come here” motion on the backside of the blade.
It lets you know that you’ve sharpened all the way to the cutting edge.
To remove the burr, place the file on the opposite side of the blade, flat against the tool, and pull back towards yourself with light pressure. This will “wipe” away the burr, and leave a smooth cutting edge. If you can still feel a slight burr, don’t worry, it’s not critical on a soil working tool to remove it completely.
Congratulations! Your tool is now sharp and ready for action.
I hope this article on how to sharpen garden tools will help you become a more competent and resilient gardener.
Compared to a dull tool, a sharp one is easier to use, more accurate and often safer (dull tools can be unpredictable). As Abe Lincoln supposedly said, “Give me 6 hours to cut down a tree, and I’ll spend the first 4 sharpening the axe.”
Once you get a taste of the pleasure of using a sharp, well maintained tool, I don’t think you’ll go back to using a dull one. 🙂