How to Sharpen a Knife with Sandpaper

Like an emery file, you can use sandpaper to sharpen your knife as well. Depending upon the grit of the sandpaper will help you determine how to sharpen the knife. Coarse grit sandpaper has lower numbers while finer grit sandpaper has higher numbers. You can wrap the sandpaper around a smooth block that you can hold onto to make sharpening the blade easier. Sharpen your knife just like how you would sharpen it with a whetstone by using the same angle and flipping between sides until the blade is sharp.

In the details below we will show you how to sharpen a knife with sandpaper. The things that you will need for this process are your knife, fine or ultra-fine sandpaper, a steady surface, and honing steel to finish the process.

Fine sandpaper has a grit of 180 to 220. It is not recommended to go any coarser than this because it will create too great of scratches and nicks in the blade. Ultra-fine sandpaper has a grit of 320. You should always go with the coarser grit (180 to 220) first then use the ultra-fine grit of 320 next. The finer grade sandpaper will take away the harsher scratches from the coarser grade sandpaper.

You hold the knife at a 20-degree angle against the sandpaper over the top of a secure, flat surface.

A 20-degree angle is good for most knives. If you are sharpening a fillet knife or a boning knife then you would hold the knife at a 15-degree angle and if you have a tactical knife then you would hold it at about a 30-degree angle.

To prevent the sandpaper from slipping tape the sandpaper down to the cutting block or other stable surface that you are using. How do you determine a 20% angle? Holding the knife at a right-angle (Straight up and down) cut (pun intended) the area in half and that will be 45 degrees. Then cut the area in half again and you will be at 22 1/2 degrees and that is pretty close to the 20 degrees that you need.

When you drag the knife along the sandpaper it is easiest to have one hand in the middle of the blade so that while you are dragging the knife across the sandpaper you can keep the blade flush with the sandpaper with even pressure. With the other hand on the handle of the knife, you drag the blade down towards you making sure that every edge of the blade makes contact with the sandpaper. You will do this about 10 times on each side of the blade.

When it feels pretty sharp after using the coarser sandpaper it is time to switch to the ultra-fine sandpaper and repeat the process by holding the knife at a 20-degree angle and dragging the blade across the sandpaper towards you while keeping the blade flush with every edge of the blade along the sandpaper. Do this about 10 times on each side again.

To finish the knife you hone it by using a rod or other hone to help get rid of any scratches, burrs, or pits left behind by the finer sandpaper. You can read more details on how to hone a knife by reading our article, “How to Hone a Knife”.