Monday, November 09, 2009

How to Sharpen a Knife

A good set of sharp knives is an absolute necessity. Whether you're carving the Christmas ham or disposing of the body of that troublesome aunt who just wouldn't shut up, your job is going to be made that much easier for having a well honed blade.
To set yourself up, all you need is a whetstone and a steel. The stone and steel can be bought relatively cheaply from your local hardware store, for as little as NZ$25-$30 combined.

This stone is a double-sided block made of silicon carbide, otherwise known as carborundum. One side has a coarse grit which is where the initial grind is made; the other side is fine, where the sharpened blade will be finished.

To bring back the edge to your blunt knife, we need to grind it on the stone. Place your stone on a cloth to stop it from moving during use; wet the rough side using water or vegetable oil. Applying firm pressure, run the length of the blade along the stone, holding it on a 20 degree angle. Turn the blade & repeat the process. After 8-10 strokes per side, turn the stone over to the smooth side & again, repeat the process. Upon completion, wipe the blade down with a cloth or paper towel, to remove fragments of metal & stone.
Click on play and watch John demostrate the process:

video

To test its sharpness, have someone hold a piece of paper vertically. Place the knife blade on the top edge of the paper & draw down - if it's sharp, it should cut effortlessly.

Once you've given your knife a good edge, its sharpness can be maintained through regular use of a steel.

The steel is constructed from stainless steel with small ridges that run along its length. It has a hilt or guard which protects the user's hand while in use. A common misconception about using a steel is that it will sharpen your knife blade. What it actually does is realign the micro-edge of the blade; everyday usage causes it to lean or fold, resulting in bluntness. Running a knife blade along the rod hones its edge.

There are many ways of using a steel; here I'll show you two, both of which I believe are pretty commonplace.

Method 1 -

1. Grip the handpiece located under the guard (the guard serves to protect your hand from being cut by blocking the blade as it travels down the shaft of the steel).

2. With the other hand, hold the knife by its handle.

3. Place the heel of the knife (the part closest to the knuckle of your index finger as you grip) to one side of the tip of the steel.

4. With the knife at a 10-25 degree angle to the steel, hold the steel rod steady and draw the knife blade, from heel to point, down the length of the steel.

5. Repeat the process for the other side of the blade. Repeat several times (maybe 6-8 strokes per side).

Again, John demonstrates this method below:

video

The second method is one probably more suited to those just beginning to learn the process. The steel is rigid, held in place by your hand & the work surface; stability is ensured, allowing for good, even strokes. The blade is run down the length of the steel, from heel to point at the 10-25 degree angle, with the added advantage being that in the event of slippage, you wont cut yourself.

video

And there you go! Follow these relatively simple steps and you'll never be found wanting in a knife fight again! Choose a method which is comfortable for you and remember that practice makes perfect. If you're still not feeling confident about your work, consider popping down to your butcher for a chat - a good sharp knife is essential in their trade, and they'll tell you what you're doing wrong.

Also, just a few tips for extending the life of your newly sharpened knife:

- use a wooden or plastic chopping board. Glass boards are unyielding and will only flatten the knife's edge

- never put your knives in the dishwasher. The scouring action of the washpowder particles will result in pitting on your blades, so clean them by hand in hot soapy water

A big "huzzah!" to John - ex-freezing worker and resident knife expert - for his help in this post (those are his heavily inked guns you see in the videos). Ta ever so much to Jen as well for use of her camcorder
:-)

3 comments:

Nigel said...

Forgot to mention: when using the steel,6-8 strokes per side is all that's required.

Miri said...

nice. I position my thumb so that it faces up the guard, towrds the steel, with the tip touching the guard (knwo what i mean?). This closes the thumb joint which apparently makes it harder to chop your thumb off

Nigel Olsen said...

I remember the day we were taught how to use a steel at tech. The tip of my thumb was sticking out over the top of the guard. On the first stroke down, *aargh!* - blade splits thumb! I've been vigilant ever since :)