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JVoye
04-14-2013, 02:56 PM
Hello all,
I've had a problem recently and was wondering if it's coming down to my actual technique in sharpening or is it the actual build of the knife (profile).
I've noticed on this particular Misono that near the tip of the knife the curvature of the tip has been somewhat distorted. If you look closely you can see that the belly near the tip has flattened out somewhat and the actual tip almost points down; difficult to explain. I'm not sure if this is due to over sharpening in this area or not sharpening the tip enough. The bevel is really even all the way up and I figured if it was due to sharpening that the bevel would be all over the place;not sure really. This effects the knife in a rolling motion as the tip tends to get caught up and snags on the board.
Has anyone else experienced this? I'm just curious because I'd like to know if it's me that's causing this so that I can prevent it in the future. Any feed back is much appreciated.
Note: Two other knives I own do not have this type of profile, although my ginga petty 120 seems to have a very similar profile and I've only sharpened it once; maybe it is the profile?
Pics-
http://s6.postimg.org/q8sk02gcx/IMG_1223.jpg
http://s6.postimg.org/pxb3nazwx/IMG_1224.jpg

bieniek
04-14-2013, 03:09 PM
This is called the birds beak.
You are pressing too hard in the area just before the tip.
Try raising the handle of the knife a little higher when youre approaching the tip.

JVoye
04-14-2013, 04:22 PM
Is there a way to repair this bird's beak?

bieniek
04-14-2013, 04:35 PM
Try raising the handle of the knife a little higher when youre approaching the tip. Then at the tip paint bevel in sharpie to know exactly what and where you are removing.

Observe closely.

Dusty
04-14-2013, 09:22 PM
http://www.youtube.com/#/watch?v=tmBTO0cA_qw&desktop_uri=%2Fwatch%3Fv%3DtmBTO0cA_qw

That is a link to one of Jon's videos about tip sharpening that will help. Until I watched the video, this happened to most of my knives.

Dusty
04-14-2013, 09:24 PM
Ok sorry. Link didn't work (I'm on a phone), just google 'Japanese knife imports tip sharpening' and the video is the first result.

mpukas
04-14-2013, 09:53 PM
I went through the bird's beak (http://www.kitchenknifeforums.com/showthread.php/5525-What-am-I-doing-wrong?highlight=what+am+i+doing+wrong) problem too. Dave, Jon, and the other guys here got me straightened out.

Dave Martell
04-14-2013, 10:17 PM
The bird's beak is a super common problem that you've created by pushing down too hard behind the tip while sharpening. My guess is that you tried to "get to the tip" a little too aggressively by pushing down and flexing the tip up off the stone. The answer to fixing this is the same as how to sharpen the tip correctly - and that's to use less pressure on the blade hand and to ensure that you raise the handle high enough to the point where you see a black streak on the stone which indicates that the tip has made contact. The motion should be one smooth swipe through the curve and up to the tip and back again.

If you by chance happen to dig the tip into the stone (as you raise the handle and push forward) then you'll know that you're just about right on your angle of approach, just went a tad too high is all, but be careful not to continue to raise the handle too high or you'll start seeing the flattening of the tip.

JVoye
04-15-2013, 04:33 PM
Thanks all,
So from here I went ahead and trimmed the bird's beak with the DMT XXC, re-thinned the edge behind the bevel and sharpened. The edge is still just a touch chunky but the actual profile looks much better. I think I still have to thin just a touch. When sharpening the tip what technique works best for you? Sharpening perpendicular with the stone or more of a vertical approach moving more horizontal when doing just the tip?
Here is a new pic after doing the work described above, thoughts?
http://s6.postimg.org/p7ezp3c5t/039.jpg

JVoye
04-15-2013, 05:37 PM
This video has also been very helpful, thank you Jon, Dave and everyone else.
http://www.youtube.com/watch?v=tmBTO0cA_qw

bieniek
04-16-2013, 12:02 AM
Now you are rounding it too much. But again, cut with it and check maye this is what you want

JVoye
04-16-2013, 12:32 AM
It's definitely rounder than it once was. I'd like to have more of the original profile back, I may try to grind a touch more or natural sharpen it to try and regain as much of the original profile as possible.
Altering the profile is new to me; once you start messing around with it the more challenging it becomes to bring it back to the original profile.

keithsaltydog
04-16-2013, 07:43 PM
Thanks all,
So from here I went ahead and trimmed the bird's beak with the DMT XXC, re-thinned the edge behind the bevel and sharpened. The edge is still just a touch chunky but the actual profile looks much better. I think I still have to thin just a touch. When sharpening the tip what technique works best for you? Sharpening perpendicular with the stone or more of a vertical approach moving more horizontal when doing just the tip?
Here is a new pic after doing the work described above, thoughts?
http://s6.postimg.org/p7ezp3c5t/039.jpg

Bird beaks are a common ailment in production Kit. wt. improper tip sharpening.Your tip fix is not bad,remember you can also lower the spine to meet the tip some as well rather just raising the edge to meet the spine.

One thing to remember in sharpening tips is there much less steel at the tip.Dave makes some good points.I go fr. 3 finger press. to two fingers at the tip also an arching motion that more follows the profile of the curve.I raise the handle just a hair at the end,not too much this gives a slightly steeper angle for for less fragile.Your tip will still be very sharp.

I used to sharpen my tips a same shallow angles as rest of blade,I think that wt. alot of sharpening this can cause bird beaks as well.Also very dished stones can be hard on tips.