How to sharpen a knife

mickri

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I have never made a knife and right now don't intend to. I have never been able to sharpen a knife. My dad was fairly good at. He tried to teach me. I never figured it out. About 10 years ago my kids gave me a set of sharpen stones for Christmas. I tried and tried again with no success. Recently I have learned how to grind really sharp tool bits for my lathe using a delta 1x42 belt sander with a light touch up with one of the stones from my kids. I had never thought about using a belt sander to sharpen a knife until now. Watched a few videos online and today had at it with two of my always dull kitchen knives and an equally dull folding knife that I use all the time for everything imaginable. My results while still not very good were better than I had ever achieved in the past.

What I have to work with is 80 and 320 grit belts and a stone with a rough side and a smooth side. Don't know the grits on the stone.

Suggestions please.
 
More than likely you're gonna get 50 different opinions..goggle is your friend..then you'll have a few more ..good luck..you'll have to pick which way works best for you.
 
I realize that I will get lots of different opinions. I am just hoping to find some combination that will work for me. One video I watched opined that you really had to have a microscope to inspect the edge and you were wasting your time without one. Others showed whipping the blade back and forth held at different angles by eye using progressively finer grit belts and leather strops. I will just keep trying different things until I hopefully find something that works for me. I may never achieve much success. I am knife sharpening challenged.
 
You are not the only one, Chuck. I use my belt sander but I lay it down with the belt horizontal and stand behind it so the belt is running away from me. I then attempt to hold the knife at a 25 degree angle and run the blade across the belt, accelerating and rounding my movement near the tip. This has resulted in some pretty sharp knives despite not using a microscope. A few passes on my water stones and I'm good to go. I probably suck at it but the stuff I cut in the kitchen and shop haven't complained yet.
 
I use mostly Arkansas stones in different grades.has worked for me for a lot of years.also have Norton stones.diamond laps.depends on the blade..pick up some good stones.learn your angles and you'll be in business ..
 
Once a knife is shaped to the basic correct geometry, I find using a 400 grit diamond 2x6 inch flat hone works really well. They are
available inexpensively on E-Bay so I have several, one in the kitchen and several in the shop. It just takes 4 to 6 swipes
at the right angle for a good tomato slicing edge. Also they are handy in the shop for fine tuning carbide cutters. Another plus
is that they don't wear down or wear out for that matter.

It makes a big difference in what kind of metal one is sharpening. Some stainless steel is really hard to get a good edge
on as well as softer steel blades. I like to use a carbon steel blade in the kitchen as it holds a good edge. My Chicago Cuttlery
stainless kitchen knives are only OK and my carbon steel blades are far superior.
 
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You are not alone in that question. After struggling for years I came upon a book: THE COMPLETE GUIDE TO SHARPENING by Leonard Lee (of Lee Valley fame). I was amazed at how much there is to know about the subject. As mentioned above there are several versions of free advice floating around on this subject but this book is worth every penny it costs. It might seem like overkill as an answer to your question but the information in this book applies to such a broad range of situations that it should be part of any hobbyist' library.
 
I have it and will re-read it. Thanks.
 
Aah, but the trick is to create the proper geometry first. For blade sharpening neophytes, that is the challenge.
I made a few of these recently: Kanna trimming tool. In my prototype I laid out the edge geometry using a belt sander, but wasn't happy with the results (oddly, that tool rest for the sander never built itself). I put the finals in a vise and shaped the edge by hand using files, which took forever. It was easy enough to use kitchen knife sharpeners for the straight edges, but the curved one is still giving me trouble - the emery-cloth-on-a-dowel approach proved too unreliable. Might have to make the equivalent of a lap or a hone to get the final edge on one.

In regards to the original topic, for already-shaped knives I use two kitchen (bench) stones: a 6000 grit whetstone and a DMT diamond that is 8000 mesh or something. Put the stone on a small cookie sheet, dribble some water on it, and do the ol' figure 8 motion, slow and light. Move to the finer grit once a cutting edge has been produced.

I recently picked up a strop block (basically a kit where a leather strop is glued to a wood block and loaded with compound) for touch-up after knife use, but have not assembled it yet.
 
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