What Grit Sandpaper to Sharpen Knives? – Detailed Guide 

So, you have a bunch of dull knives in the kitchen but no fancy knife-sharpening tools? Did you know that good old sandpaper would work equally well? But how do you know what grit to choose? 

There’s a range of different grits to choose from and each grit serves a specific purpose. If you are inexperienced, you would probably feel lost. This article has been put together to help you select just the right grit for sharpening your knives.

If you’re looking for a more efficient way to sharpen your knives, check out our detailed review of the top knife sharpeners on the market.

What Grit Sandpaper to Sharpen Knives? – Find Out

I recommend starting the sharpening process with 600-grit sandpaper and subsequently moving to higher grits to achieve a fine finish. 

However, before you begin sharpening, assess the condition of your knife. If it needs repairing, you must address that issue first and use lower-grit sandpaper. 

Now that you have a general idea about where to start, let’s dig deeper into the various sandpaper grits out there and how you can use them to get razor-sharp knives.

What is Sandpaper Grit?

The sandpaper surface is made up of abrasive particles. During the production of sandpaper, screens with holes have been used that filter these abrasive particles. 

Essentially, large particles pass through large holes. Therefore, less number of holes per square inch are present on the screens. Coarse grits have larger abrasive articles on them, which is why they are known for smaller grit numbers.

Alternatively, fine-grit sandpaper has smaller abrasive particles on it. These are given higher grit numbers considering more holes are present on the filtering screens used for production.

Coarse Grit sandpaper

These are sandpapers with grits ranging from 100 to 400. Coarse grit sandpaper is ideal for removing debris from your knives and grinding down burrs. If your knife is ultra dull and rusted, begin the sharpening process with coarse grit sandpaper.

These sandpapers are particularly handy when dealing with rusted knives. If you happen to reside on the Queensland coast in Australia, I’m sure you would have quite a few rusted knives stowed away!

These sandpapers can help you create a double bevel. While the sandpaper is busy reshaping the blade of your knife, it will simultaneously restore any snapped points. 

Note that these sandpapers should not be used for very delicate knives as there is a high chance of damaging them. 

Medium Grit Sandpaper

These are sandpapers with grits ranging from 400 to 700. If you began the sharpening process with coarse grit sandpaper, you most likely have a scratched knife blade by now. Medium grit sandpaper will help you get rid of those. 

Furthermore, it can also remove light burrs and smoothen the edge of your knife’s blade. This is the ideal sandpaper to select if you have a clean and not-too-dull knife. 

Medium grit sandpapers will give you a bevel on which you can work further to get a full-length sharp edge. 

Fine Grit Sandpaper

These are sandpapers with grits ranging from 1000 to 1500. Apart from being effective knife sharpeners, these sandpapers can also be used to polish the knife’s edge. 

Once you are done establishing a bevel angle with your medium grit sandpaper, you can switch to using fine grit sandpaper for creating a factory edge. 

If your knife is relatively sharp and only requires a good polish, you may start off the sharpening process with a fine-grit sandpaper. Additionally, these sandpapers will also rid your knives of any light scratches. 

Fine-grit sandpapers produce quicker results as compared to coarse and medium-grit sandpapers.

Extra fine Grit Sandpaper

These are sandpapers with grits ranging from 2000 to 2500. The 2000-grit sandpaper is ideal for polishing the edge of your knife blade. Moreover, these will remove any blemishes from your knives and have them look shiny and pretty in no time!

These sandpapers will create a mirror finish and provide straight razor sharpness to your knives. 

Note that using very fine grit sandpaper excessively may damage the edge of the blade. Always use a block for support when you are working with sandpaper so that all your hard work won’t get wasted.

Grit Measuring Units

Two major grit gradation systems exist CAMI and FEPA. FEPA stands for Federation of European Producers of Abrasives and is more widely used worldwide.

CAMI stands for Coated Abrasives Manufacturers Institute. This grading system is limited to its use in the USA. 

Sandpaper grit that is sized using the FEPA system has the letter “P” before the grit number. Although the two systems are not identical, they are quite comparable. This is especially true for lower grit sandpapers. 

For instance, 40 grit (CAMI) is a close match with (FEPA) P-36 or P-40. However, 400-grit (CAMI) is a close match with (FEPA) P-600 or P-800. 

If you are having trouble switching between the two systems, refer to the sandpaper manufacturer’s chart for conversion.  

Knife Sharpening With Sandpaper

Now that you are aware of which grit sandpaper to select for sharpening knives, let’s move on to the technique that you should employ.

• Begin the process with 600-grit sandpaper. Tape it down to a flat surface, so that it stays fixed. 

• Then hold your knife at an angle of 22° against the surface. It doesn’t have to be exact! Just hold your knife at a 90° angle against the surface. Split this in half to get a 45° angle. Another split will provide you with the desired angle. 

• Hold the knife by its handle with a firm grip. Move the knife onto the sandpaper. Repeat the strokes while keeping the pressure and angle constant. 

• You can change sides after performing three strokes. 

• Once you have achieved the desired result, repeat the process with a finer grit sandpaper.

• During the sharpening process, keep a regular check on the sandpaper by running your fingers along the sandpaper. If it seems worn out (too smooth), move over to a new section of sandpaper and resume the sharpening process. 

• Check the edge of your knife’s blade regularly. Once you are satisfied with the sharpness, remove all sanding particles from the blade. Your knife is now ready to slice away!

Comparing a Knife Sharpener and Grit Sandpaper

Knife sharpeners contain multiple sharpening stones. Some basic differences between a knife sharpener and grit sandpaper are as follows:

• Sandpaper is very cheap compared to knife sharpeners. If you are a beginner, I would recommend that you learn basic sharpening techniques on sandpaper. Once you get the hang of it, you can try out other superior sharpening tools.

• Knife sharpeners are durable, whereas sandpaper requires frequent replacement. 

• You will get quicker results when using a knife sharpener, as compared to using sandpaper. 

• Purchasing sandpaper is much more convenient as compared to other knife sharpeners. 

• Knife sharpeners are exclusively made for sharpening knives. Therefore, using a sharpener for your knives proves to be a more efficient choice.

• Sharpening your knives too often with sandpaper might eventually damage your knife blades. The metal pores of the knife blade might disintegrate or rust away. On the contrary, knife sharpeners are less damaging.