How to Sharpen A Knife

We all have them. That incredibly dull knife that you have to force through even the thinnest of materials. Not only is this aggravating but it can also be dangerous. I aim to help you with this guide to take your screwdriver dull knives into razor sharp tools for both your safety and sanity. This guide is broken down into several sections as follows: 

Sharpening a knife for beginners with a whetstone

Sharpening a knife to a razor edge

Sharpening a knife coarse or fine?

Sharpening a knife with steel (rod)

Knife Sharpening Kit(s)

Sharpening a knife for beginners with a whetstone

There are a lot of tips and tricks out there for how to sharpen knives but the best advice I can give is to keep it simple and don't over think it. You can ruin a blades temper by trying to use a grinder so stay away from those. For the beginner the best thing to start with is the oldest method in existence. A whetstone. Knowing what steel your knife is composed of is helpful but isn't as important as your angle. The angle of sharpening dictates how sharp you are able to get your blade.

What angle should I sharpen at? Glad you asked. You will want to sharpen at a 22.5 angle. No, you don't need to have a PHD in mathematics or geometry to achieve this. Its actually quite simple to achieve this angle. All you need is a piece of standard printer paper 8.5 x 11 inches.

First you are going to fold your paper at a 45 degree angle from the top, then fold your paper over again and line up your edge. You now have a 22.5 degree angle. You can find a video of this technique here. (timestamp from 2:08 to 2:52)

Once you have your angle achieved, you will push the blade forward along the stone on each side until you have your desired sharpness. If the blade is very dull you will want to start with the rough or lower grit side of the stone.

It is important to note that a little bit of lubricant on the stone helps this process along as well. You can use wd40, 3 in 1 oil or really any lubricant to include water. 

Like anything else, sharpening with a whetstone takes a little practice to get good at but once you get comfortable with it you will be able to put an edge on your blades quickly from anywhere.

Sharpening a knife to a razors edge

Possibly the most important part of getting a blade to a razors edge is sharpening your blade at a consistent angle with light pressure. In order to obtain that molecular sharpness you are aiming for you need to eliminate the bur that forms on the edge. To do this you will need multiple grit levels of stones and a leather strop.

The angle that you are sharpening at should be in the 15 to 25 degree range but as stated before you must remain consistent throughout the sharpening process. Variations cause you to have a rounded edge instead of a symmetrical one which will cause resistance when cutting. 

As opposed to sharpening a blade to a "normal" sharpness level you will only want to sharpen applying pressure on a backward stroke of the blade. Meaning you will want to drag the edge instead of pushing the edge toward the stone.

If you already have a blade that you have decently sharp you will want to maintain the same angle that you started sharpening with. The idea is to polish and refine the existing symetry of the blade, not redefine it. In extreme cases where the blade is damaged or has small chips you would start with a very low grit and work your way back up. In this example you would be good to redefine the edge angle.

Assuming your blade is in good condition, you would want to start with a 400-1000 grit stone. Apply pressure on the edge when dragging the edge away from the stone equal times on each edge of the blade. Make sure your stone is lubricated with water, oil or whatever the stone manufacturer calls for. 

Move through the grit progressions on the stones until you have reached the 8000 grit level or whatever the highest level of stone you have access to is. Remember to keep light pressure and consistent angle. This isn't about removing steel from the blade but it about refining the edge. 

After you have moved through all the progressions on your whetstone it is time for the icing on the cake. That is the leather strop. For leather stropping you always pull the edge of the blade away from the leather. You never push the edge along it. This will damage your strop. At this point you should be essentially using the weight of the knife with virtually no pressure on the edge as you pull it away. Remember to maintain that consistent angle.

If you followed these steps correctly you will have a razor sharp edge that will cut through anything with ease. Remember that it does take practice to achieve a consistent angle but there are angle trainers and other available tools that can help you along this journey.

Some whetstones for sale are here.

 Sharpening a knife coarse or fine?

If you are just putting an edge on a knife for the first time then you will want to start with a coarse stone. The course or lower grit stone will remove more material from the edge of the knife allowing you to set the the angle. 

If you are refining the edge of the blade and it already has a decent edge that you wish to polish further you will want to use a fine stone or a higher grit stone. 

For those not familiar, grit count is determined by how many particles can fit through a 1 inch filter at the factory. So if 36 particles move through the filter the grit is larger than if 8000 move through the filter. The grit translates to how rough the stone will be determined by the size of those particles.

You will want to examine what you are aiming to achieve and allow that to guide you on what grit stone you need for sharpening.

Sharpening a knife with steel (rod)

 Like the methods mentioned above, the most important thing to keep in mind when sharpening is the angle at which you are sharpening. You need to make sure that are consistently sharpening at whatever angle you choose. The sharpening angle is typically 15 degrees for japanese knives and 20-25 degrees for western knives.

There are several different rods you can get and each of them will perform a slightly different function. Steel rods are the most common rods you will find for sharpening, however you will also see ceramic and diamond steel rods. The principle difference is the amount of material that they remove. A steel and diamond steel rod will remove more material from the knife and that puts them in the sharpening category. A ceramic rod however is a honing rod. Honing polishes the already defined edge. 

In order to sharpen with a rod you will want to place the heel of the knife (the part where the edge starts closest to your hand) at the top of the rod (closest to where you hold the rod.. The idea is to hold a consistent angle of the blade and push the blade along the rod away from you having the tip of the blade exit at the tip of the rod. 

One way to think of it that may help is to approach it like you were whittling a stick. Keep a consistent angle and apply light pressure and "cut" the stick. Repeat this on the top then duplicate the same angle on the bottom of the stick always away from you.

If you have trouble doing this "free hand" where you are not anchoring the rod to anything other than you hand, you can try placing the rod tip down on a cutting board and keeping it completely vertical. This allows you to perfect your angle on each stroke of the blade while also being safe and not cutting toward your hand.

You can find rod sharpeners here.

Knife Sharpening Kit(s)

There are a ton of sharpening kits available in the market. You can get motorized sharpening kits such as we carry or you can opt in for whet stones or rod based systems. Ultimately you will want to think about your needs for your specific situation before investing the money.

Some sharpening kits can cost thousands but these are for more industrial operations. Others are much less expensive and can cost just a few dollars. Whet stones are highly recommended due to availability, cost, and the basic skills required to operate. In addition whet stones will familiarize you with the angle required for sharpening your blades consistently.

Something to consider when thinking about a sharpening kit is the quality of the blade you are working with. If working with a high quality blade you will not want to use a kitchen sharpener or belt driven sharpener as these will ruin a high quality knife in a few years of use. The reason for this is that these sharpeners are designed to give the blade an edge via removal of material. After a few years of use you will notice that the symmetry of the blade has degraded due to the material removal that took place when sharpening.

If you are having trouble maintaining your angle when sharpening on whet stones there are several kits that work on a keeping system such as a guiding rod. These systems ensure that you are maintaining the angle required to get that edge you are looking for. They tend to be more expensive than whet stones but will not allow you to deviate from the angle they are set at. 

You can find guide rod based kits here. 

No matter what you are doing remember to have fun, be safe, and always Forge Ahead.