Author Topic: So how do i sharpen a knife like this  (Read 11870 times)

Offline Jimmy R Jørgensen

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So how do i sharpen a knife like this
« on: July 13, 2016, 09:43:47 pm »
Sorry about the erhh poor Subject name. I don't know what do call this knife edge?

How do i sharpen this on (if at all) using the Tormek??

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Offline Jan

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Re: So how do i sharpen a knife like this
« Reply #1 on: July 13, 2016, 10:31:22 pm »
Jimmy, when you will sharpen the knife on Tormek than simply use the corner of the grindstone as shown in the picture bellow.  :)



Jan



Offline Jimmy R Jørgensen

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Re: So how do i sharpen a knife like this
« Reply #2 on: July 13, 2016, 11:26:36 pm »
Now that doesn't look like a easy task to do?..
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Offline Herman Trivilino

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Re: So how do i sharpen a knife like this
« Reply #3 on: July 14, 2016, 02:28:01 am »
The correct way to describe that knife is a concave edge, as opposed to the more common convex shape seen on many kitchen knives and pocket knives.

I agree that it's a very difficult proposition to sharpen such a knife. I did have a cheap paring knife shaped like that, and when it got dull I just reshaped it so the edge was straight rather than concave.
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Offline Ken S

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Re: So how do i sharpen a knife like this
« Reply #4 on: July 14, 2016, 02:47:50 am »
Jimmy,

Nice to see you posting. This bird's eye knife reminds me of the hand cut dovetails class I took with Ernie Conover. Our project was a Shaker candle box with hand cut dovetails. Most of the student boxes, mine included, looked like student work. Ernie told us not to become discouraged. If we made fifteen boxes and worked hard, we would be proficient.

You can learn to sharpen knives with concave edges. Jan has shown you the right technique. All you need to add is work and practice. I suggest starting with some knives you own.

Courage and patience, my friend!

Ken

ps to Jimmy and Jan: Very nice photographs!

Offline Elden

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Re: So how do i sharpen a knife like this
« Reply #5 on: July 14, 2016, 07:23:48 am »

Jimmy,

Recently our local lumber yard asked me to sharpen some scissors for them. I just about refused for various reasons (we were in the process of moving and I had not done any scissors for hire for several years). But I decided  to try to help them out. There were 3 pair of scissors, 2 were offset carpet fitter's duckbill scissors similar to these:

http://www.homedepot.com/catalog/productImages/400/a9/a9bc6dbb-8fe8-4a82-81c0-5cd1016fcb41_400.jpg

Those were easily done.

The other pair was in a leather case, I did not see them until later after getting home with them. If had seen them there at the store I probably would have said I could not do them.  They are made by Buck and come apart for easy clean-up (it also made it nice for the sharpening procedure). They have a concave on one of the blades.

http://basseast.com/wp-content/uploads/2010/11/buck_shears.jpg

 The sharpening machine I used,  has a grinding wheel 12.5 mm wide. One edge of the grinding wheel has a small radius.
 
I fretted about doing them for several days before doing them. After simulating doing them several times with the machine turned off, I very lightly tried it with it turned on. By using the edge with the radius on the concave portion of the scissors blade and flattening out to the whole face for the flat portion of the blade, it went very well.

I feel that simulation runs were key in getting the movements figured out to accomplish the sharpening procedure.

Elden

Offline Jimmy R Jørgensen

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Re: So how do i sharpen a knife like this
« Reply #6 on: July 14, 2016, 07:42:52 am »
I think that i will tell the guy the truth.. that i'm willing to give it a try, with a little help from my friends (you all). But that it is my first with concave knife edge, so the outcome is erhh unseartant.. Mayby he will say, give it a go, or maybe not.. You'll get a full update.

Thanks all.
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Offline Rob

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Re: So how do i sharpen a knife like this
« Reply #7 on: July 14, 2016, 08:32:55 am »
You can publish a photo of the court summons :-)
Best.    Rob.

Offline Jan

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Re: So how do i sharpen a knife like this
« Reply #8 on: July 14, 2016, 09:55:47 am »
Agreed, Rob. I love antiques but not such a gun shown in the picture.

Here there is an alternative picture of the same Smith & Wesson karambit knife.



Jan

P.S.: From my personal experience I can confirm that the concave edge is great for peeling boiled potatoes. I maintain the inside curved edge with a ceramic steel of larger diameter, because I do not want to wear off the corners of the expensive Tormek grinding wheel.
« Last Edit: July 14, 2016, 10:37:39 am by Jan »

Offline Ken S

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Re: So how do i sharpen a knife like this
« Reply #9 on: July 14, 2016, 10:47:52 am »
Jimmy,

This is a situation which proves the value of a black marker, the stone grader (graded fine), and a light touch. These will allow you to carefully monitor your progress while very slowly removing steel. As you gain experience and confidence, you can work more quickly.

When I help my granddaughter learn a new piece on the piano, she plays it very slowly, taking time to name the notes and then count. As she becomes more proficient, we increase the tempo.

Patience and persistence carries the day.

Ken

Offline Jimmy R Jørgensen

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Re: So how do i sharpen a knife like this
« Reply #10 on: July 14, 2016, 10:52:42 am »
Thanks Ken.. belive me i will go slow.. babysteps..

As to the gun. it is softguns. but still a gun. We're not allowed to have gun in Denmark, only af few kind for hunting that's all.. it is only a few people that have guns here.
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Offline Ken S

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Re: So how do i sharpen a knife like this
« Reply #11 on: July 14, 2016, 11:34:14 am »
Jimmy,

Do an online search of "Steve Bottorff youtubes". Your time will be very productive with many well done videos, including one which specifically covers sharpening knives with inside curves.

Ken

Offline Jan

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Re: So how do i sharpen a knife like this
« Reply #12 on: July 14, 2016, 01:57:02 pm »

As to the gun. it is softguns. but still a gun. We're not allowed to have gun in Denmark, only af few kind for hunting that's all.. it is only a few people that have guns here.

Jimmy, thanks for the clarification of the gun origin. You have calmed me down.  ;)

Jan

Offline That Sharpening Guy

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Re: So how do i sharpen a knife like this
« Reply #13 on: July 18, 2016, 09:47:02 pm »
Jimmy, I had asked a similar question a while back so maybe some of the answers I was given may help.

Good luck!!

http://www.tormek.com/forum/index.php?topic=2407.msg11995#msg11995

Offline Jan

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Re: So how do i sharpen a knife like this
« Reply #14 on: July 19, 2016, 09:07:00 am »
Good reminder, TSG!  :)

Your wave shaped karambit knife was surely much more difficult to sharpen because of the double curved blade and also the more pronounced blade concaveness. Some sharpeners understand the second blade curve as a large serration.

What is your current procedure to sharpen such a knives?

Jan
« Last Edit: July 19, 2016, 09:19:50 am by Jan »