Finding the Correct Angle for Knife Sharpening
Tips for sharpening with a belt sander; with or without an angle guide
When sharpening a knife or similar tool on a 1x30 belt sander, using the correct angle is a key factor to the outcome and functionality of the blade or tool’s edge. You may be wondering what sharpening angle is ideal for your project and we’re here to help you decide.
With a little practice it’s easy enough to visually study and match the current angle of a knife. This is especially true if the knife was previously professionally sharpened and has a nice even edge. This is a technique you may not master straight away and it leaves a bit more room for error. For beginner sharpeners we suggest practicing on knives you don’t mind messing up, even buying a few inexpensive knives from a second hand store to practice on can be really helpful. Repetitive practice is key to quickly becoming a better sharpener.
The angle of your knife or tool’s edge is determined by what kind of knife you have. The chart below shows our general suggested angles.
A factor to consider when picking your angle is how you will be using your knife. A small (or lower) angle might work great for a small paring knife used for cutting produce, but would not be ideal for a cleaver used to cut through chicken bones. A thin edge on a cleaver chopping such hard objects would be easily damaged and dulled. I myself have a designated vegetable cleaver which would work great with a small angle around 17-20 degrees. In this instance I would stray a little bit from the chart above.
If you know the quality of metal your knife is made out of you can also consider that for your sharpening angle. A prime example is that most Japanese cutlery has a high hardness which can be sharpened at a smaller angle. Softer metals would have too weak of a cutting edge at the same angle. If you aren’t sure what kind of metal you are working with, it’s a safe bet to follow our chart.
Once you know the angle you are trying to achieve, it’s time to put it to action. A low grit, such as 120 or 220 will result in the removal of the most metal as well as creating a good starting burr. If you aren't feeling confident start with a slightly higher initial grit, maybe a 320 or 400. You can switch to a lower grit if you aren’t creating the initial burr you need. Something that will help you maintain an angle across the length of the edge is managing your pressure. Too much pressure can cause the belt to grab the knife and may make it less stable. Light pressure allows you to make a nice stable pass across the blade or tool’s edge. If the knife you are working with already has a uniform bevel this will be easy, but if there are inconsistencies you will need to apply more or less pressure in different areas accordingly. Take your time and aim for a steady flow across the edge of the blade, and instead of dragging the blade at a perfectly linear path follow the curve of the knife.
Another option is the use of an angle guide. The guide works on most 1”x30” belt sanders and has a spring clip that slides to fit easily over the platen. Once your guide is on, you can install your abrasive belt and adjust your platen in such a position that allows the belt to run unobstructed. There are two small knobs on the side that allow you to adjust the angle. The guide provides you with a plate at the angle of your choice which your knife lays flat on. Now you can smoothly run the edge across the belt without concentrating too specifically on the angle. The angle guide is not to be used with a leather stropping belt, leather stropping belts require edge trailing blade orientation. Refer to the video below for help with installation and use of the angle guide.
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Keep up the good sharpening!