2010-01-09 - How to sharpen a knife

Learning proper knife care can extend the life of a blade by years. A good knife is worth the money so long as you treat it right. A dull knife is obviously less effective- and actually a lot more dangerous to use because you begin to use the knife with bad form. The more dull a knife is- the more force you need to use and that increases the risk of hurting yourself.

One of the oldest and most effective tools for sharpening a blade is the whetstone. It takes a lot of practice to get the technique down- but is well worth learning. The knife is one of the oldest and most useful tools. You can find uses for them everywhere; work, camping, gardening and the kitchen. I always have one handy- it helps when you need to MacGyver things. But what good is a knife if it's not sharp?

A whetstone will only run you a few bucks but it can save you a lot of money in the long run if you don't need to have someone else sharpen your blades. I used this helpful guide to get some of the basics of sharpening blades. I'm not going to regurgitate their instructions verbatim- but I'll address a lot of the key points I took from it.

Some things to consider are what you want from the sharpening. There are different ways to do it with different outcomes. You can get a really sharp edge that won't last very long- or sharpen with the longevity of the blade in mind. If it's a really good knife you're probably looking more for longevity- but it will take a bit more skill and patience to achieve that.

A whetstone typically comes with two sides- one side is for coarse work and the other side for fine sharpening. Start with the coarse side to get out any large defects and impurities. Hold the blade at a 22.5 degree angle (half of a 45 if that makes it easier to visualize) against the whetstone. Push the blade across the whetstone in a forward motion- simultaneously engage the entire blade from tip to the hilt in a rocking motion while maintaining the forward movement.

On the coarse side you'll be able to feel the stone catch the major impurities. Once you work them out you should be able to move the blade smoothly across the coarse side without it snagging on anything. Once all the big impurities are out- run it 10 times on each side of the blade- and then switch to the fine grit side. I like to use a damp paper towel to wipe the blade clean before switching to the fine side. While sharpening you generate both metal and stone debris that if carried over to the fine side can make a more jagged finish. Think of the fine grit side as more of a polishing surface- only for the finishing touches.

Repeat as necessary. The more coarse side will remove material faster so you can hone the blade- but be careful not to take too much material away while trying to get the right shape. Blades will wear down eventually and the more material you remove the faster that will happen. The fine side is more for finishing touches- not for major changes in shape.

Things to remember:

• 22.5 degree angle
• Grip the handle with one hand- apply downward and directional pressure to the blade with the other.
• It's called a whetstone, not a wetstone. Water can actually ruin the stone.
• It doesn't matter if you go forward or backward on the stone- so long as you are consistent with every pass. Never use a back and forth motion- pick a direction and stick to it.
• Get all the big impurities out using the coarse side- smooth it out with the fine side.
• After you finish sharpening the blade wipe it clean with a wet paper towel and dry it.
• Test the sharpness of the blade by running it down a piece of paper- if you did it right there will be a noticeable difference from when you started.

If anyone has anything they need sharpened let me know- I can use the practice.