Sharpening knives with stones

Wentworth

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Here's the method I use to sharpen my knives using sharpening stones.

As a disclaimer, I am by no means an expert sharpener, but the forum doesn't currently have a sharpening demonstration by a member. If any of our amazing knife makers would like to put one together, I'll make it a sticky.
My techniques might be considered incorrect, but I'm always happy to learn. Feel free to share your own techniques and experiences.


What type of stone?
I use water stones, which require water when used and oil stones which (as the name might suggest) require oil on their surface during use. Other types such as diamond stones don't require any liquid. As a kid, I didn't use liquid with my stones and they became clogged with the metal being sharpened. I've used bicarb soda and steel wool to clean my stones in the past.

Does it need the stone?
In the following drawing there are three types of edges.
edges.jpg
(from left to right)
1.) a knife whose edge hasn't worn away, but has folded over, or deformed. This edge doesn't need working on a sharpening stone, it just needs a strop, or realigning on a steel or crock stick.
2.) a knife whose edge has worn away, leaving a flat spot. This edge does need working on a sharpening stone.
3.) a knife whose edge has been sharpened on a stone, or whose edge has been realigned. This one is good to go.

Sharpening a scandi grind on a stone
A scandi grind is easy to sharpen as you can feel the large face of the bevel "lock" into place on the stone.
Once the bevel is flush with the stone, I push it over the surface of the stone, from the start of the edge to the tip.
I sharpen my knives with the edge leading, rather than trailing, as this will require less work later on with removing the burr.

This drawing shows a dull edge being worked on one side until a burr forms.
sharpen1.jpg

Some people like to swap sides every X number of strokes, but I work one side until I can feel a burr form. I test to feel for a burr by running my thumb across (not along the length of edge) the blade.
test1.jpgtest2.jpg

I then swap to the other side until I feel a burr form.
Note: if the edge was very very dull, I would probably alternate strokes, so as not to end up with an edge that was uneven.

Once I have worked both sides, I then alternate from one side to the other with each stroke, going lighter and lighter in pressure.
sharpen2.jpg

Sharpening a knife with a secondary bevel
A knife such as a swiss army knife, or a kitchen knife has a secondary bevel and is more difficult (for me) to sharpen than scandi grind knives.
The reason is that I can't feel the bevel lock against the stone in the same way I can with a scandi. I use a different technique to make sure the smaller bevel is flush against the stone.
As the following diagram shows, I lie the blade flush against the stone.
Notice the gap formed between the bevel and the stone.

I then tilt the spine of the knife up until I see the gap disappear.
non scandi.jpg
I'm aiming for around a 20 degree angle here (it's not exact in the diagram).
(If it's easier, think of a 90 degree, cut it in half to get 45 degrees. cut that in half to get 22.5 degrees, which is close enough for me).

Once I have this angle, holding the knife in my right hand, I place the thumb of my left hand against the spine of the knife and the stone. This helps me maintain that angle as I sharpen.
I then use the same sharpening technique for the formation of a burr as listed for the scandi grind.

Removing the burr
If the burr isn't removed, it can tear off quickly and leave you with a dull knife. It can be removed by:

Stropping http://bushcraftoz.com/forums/showthread.php?5245-Stropping

Adding a micro bevel http://bushcraftoz.com/forums/showthread.php?5029-Putting-a-micro-bevel-on-a-scandi
 
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Wentworth

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I've not heard of kero being used before. Thanks Greatbloke.
Do members have any other tips to share?
 

Howling Dingo

Richard Proenneke
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Nice one mate..I got a old 60 year old stone and also use kerosene to clean it up.
 

Bernoulli

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You can use poor man's Prussian blue, a Sharpie, to mark the edge. This will tell you how close you are to the original angle as you sharpen. Once you have a feel for the correct angle at home, you should be able to reproduce it in the field.
 

MongooseDownUnder

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The key to a sharp edge is repeating the same angle every time the exact angle is less important to sharpness than the angle being the same with every pass on the stone. Often people try to use a stone which is not flat which will cause the angle to keep changing as they run along the stone. if you need to flatten your stone you can use a cinder block of flat level area of rough concrete or rock.
happy sharpening
 

Smarteee

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Personally speaking, I prefer the micro bevel edge. I find it easier to sharpen and (my) knives seem to hold the edge better. I use a small DC3 sharpener from Ray Mears bushcraft store. Gripping each end of the sharpener between the tips of thumb and forefinger of one hand, use the diamond side first. I draw the blade both towards and away from me, moving across the width of the sharpening surface. Alternating each side of the blade, for each stroke, 10 times. Then turn the sharpener over and repeat on the ceramic side for between 30-50 times (alternating each side again). Then I lightly strop on the back of my leather belt (no paste). Sharp enough to shave hairs from my arm. :)
 
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Any tips on where and what water stones to get for optimal sharpening? I have seen the Ice Bear set on Ray Mears and watched his vids they are nearly $200AU landed.

cheers
 

MongooseDownUnder

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I know Carbatec sell some and they certainly are not anywhere near that price. Just don't go and get a 10000 grit stone because for knife sharpening they are over the top and you will spend hours and only result in a polished knife. I use water stones to sharpen my woodworking tools. I would generally not recommend them for everyday use because they can be brittle and break easily if knocked around. I wouldn't go any more course than 4000 grit.
cheers
Adrian

(source, 20 years experience as a Butcher)
 
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Thanks, MongooseDownUnder!

Carbatec has the equivalent setup to the ray mears one for 1/2 the price. Should a 4000 grit waterstone be used with a Nagura Stone?

Pretty keen to get some decent stones as the bunnings one I have, just cant seem to get a good edge on anything.. probably operator abuse :)

cheers
 

MongooseDownUnder

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You don't have to use a Nagura stone if you don't want to but it helps you build up a slurry quicker. Without a slurry the stone will not sharpen effectively and it can sometimes take a little while to get a slurry. I use a Nagura on watersones normally. When I am out bush I don't use a waterstone though. But to answer your question you can use a Nagura stone on any waterstone you choose. If you are having trouble getting a good edge it is probably not the stone that is the problem. although some stones can be quite hard to sharpen with. The steel that knives are made of varies a lot and some are quite difficult to get a good edge (harder steel) however when a knife made from harder steel is sharpened the edge will generally stay sharp longer. What sort of knife are you trying to sharpen?

cheers
Adrian
 

Bernoulli

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You can get an excellent edge on any kind of stone. You can get a usable edge with any abrasive surface. I've watched men in Colombia sharpen machetes on concrete curbing; sharp enough for their purposes. Water stones are good. I have them, just as I have carborundum, Arkansas, ceramic and diamond stones. I've also used wet-or-dry paper on plate glass. Technique is more important than the stone you use.

I generally defer to the Japanese belief that their fine traditional knives should be sharpened on water stones. An excellent professional sharpener friend uses a Tormek for the final polishing on Samurai swords. I'm working up the nerve to touch up a nice Nakiri with my paper wheels.

In the field I carry a Schrade Honesteel and a Fallkniven DC-4.
 

Joe

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Great tutorial wentworth, I wish I had found it when I started out.

I have battled with sharpening over the years and tried a wide range of stones, diamond hones and strops yet I think the most important factor after consistent angles is the burr. Some videos i followed originally said do "x" amount of strokes per side which often didn't remove enough material to get a burr and thus i never ended up with a sharp edge. It's all about the burr.

Before switching sides you should always confirm you have a burr along the full length of the blade. Any places along the length where you can't feel a burr, simply work those areas until you can. Then switch sides and repeat through to the finest stones you have.

I often use pull strokes when I am having difficulty getting a burr as they tend to leave a larger amount of burr material on the edge. Then on the last few passes on the finest stone you can use push strokes to try to slice the water off the stone which will remove the burr from the edge.

Follow with a strop and you will be popping hairs from your arm in no time.

Joe.
 
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Joe

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Oh and the best combo regarding stones in my opinion are the ceramic Japanese aluminum oxide stones. I use a 400grit, a 1000grit and a 3000. If you have a strop you could easily do away with the 3000 but it is nice to have. The 400 cuts nicely and then the 1000 does a semi cut /polish and the 3000 polishes the edge. The strop then builds on the polish leaving a mirror edge.

The 3000 also works well to retouch an edge after it has been worked with but before it needs a full re-sharpen.

Last birthday the wife bought me a 3 stone set of the above stones from the "chefs armory". Not cheap but they will last a long time. They have the fine sharpening taste of natural stones what ever that means.
ImageUploadedByTapatalk1373771332.537936.jpg

The trade off has been keeping the kitchen knives sharp, which I secretly enjoy. Sharpening is very relaxing.
 
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Thanks for the great tips.. I think I am to impatient to get a good edge, well at least with anything not used in the kitchen ie, thin and soft. Thicker blades I just cant seem to make "dangerous sharp" even using a spyderco sharpmaker.
 

Bernoulli

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Trying to sharpen "thick" blades on the Sharpmaker can be a problem. Put some Sharpie along the edge. You may find that Sharpmaker angle is forcing you to work above the edge. Re-profiling on the Sharpmaker will take a LOT of time. If you would like to manually re-profile, I'd recommend diamond stones. DMT and EZE-LAP both make them. I prefer EZE-LAP, but they'll both do the job.
 

CSGSurvival

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Yep, kerosene is the way to go for cleaning oil stones. Although I've used windex with good results also ;). Pretty much any de-greaser should do the job. Then just brush it off with a wire brush.
 

Bezerker Viking

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BushcraftOz Meet Sharpening Workshop with Wentworth.

[video=youtube_share;DRJ3STJCXic]http://youtu.be/DRJ3STJCXic[/video]
 

Wentworth

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Once again, thanks for editing out the embarrassing moments BV :)
 

Skandiman

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I have been using White Spirits to pretty good effect but I'll give kero a go next time I use an oilstone. These days I mainly use water!
 
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