How do you properly sharpen a kitchen knife?

It sounds silly, but I have all the sharpeners one could buy, steels, ceramic, diamond... but no matter how I rub, pull or grind, my kitchen knifes can hardly cut through the skin of a tomato.

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jtobako8 years ago
That's because you are trying to get a classic razor edge to the blade. You don't want that. A knife steel will put an extremely fine serrated edge on the blade, but it has to be re-done frequently because a kitchen knife is ment to be easily sharpened (and thus dulls easily). Watch a chef sharpen their knife. They draw the whole cutting edge along the steel, pulling away from the edge. That puts a very fine, rough bur on the edge-the beginning of a wire edge-which will easily cut soft things like tomato skins and flesh. Second part is HOW you cut. Tomatoes are cut with a slicing action, not a chopping one. Think very fine saw.
Re-design8 years ago
Cutting the skin of a ripe tomato is one of the hardest things to cut. The serrated edge comment of seandogue's is a good one. One of the things that will ruin a sharpening job every time is letting the angle change. Every stroke needs to be at the exact angle or you round the edge. Don't forget to remove the "hook". You'll read about it in the links provided by others. To put a really good edge on a high quality knife by hand using stones will probably take half an hour or more after you know what you are doing. Good luck and keep practicing.
seandogue8 years ago
All good comments about sharpening...I have only one thing to add. Serrated blades... I used to use my fancy schmancy French Cook's knife to cut tomatoes, but I've finally become a convert to serrated blades for tomatoes and other "squishy" things like peaches. Why? because they work every single time and produce a perfect cut. Now the cook's kife has been relegated to meat, crunchy veggies and similar things...it's just a matter of practicality.
kevinhannan8 years ago
I cannot argue against doing stuff properly.

However, sometimes (most times) I just can't do it the proper way...

What I do, about 3 times a year, is get my angle grinder with a fairly fine abrasive disc and use that to sharpen my kitchen knives (I use a coarser grade to sharpen my garden spade) and it all works a treat. So much so that everytime I sharpen up the knives my wife cuts her fingers open - without fail.

That reminds me, it's time to sharpen them again!
I forgot to say, I grind both sides of the blade at about 15-20 deg angle
It depends on several factors (type of knife edge, type of metal, etc.) but here are a few good tutorials to start with:

https://www.instructables.com/id/Sharpen-a-knife/
https://www.instructables.com/id/Knife-Sharpening-Tricks/

This book is also very good for beginners who have a slew of sharpening gadgets but can never seem to get a sharp edge:

http://users.ameritech.net/knives/sharpeningmadeeasy.html
(Note: You can also buy this book from Amazon but it is more than twice the cost there)