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Blackstone Knife & Tool - Handcrafted by Tim Johnson and Tonya Reed, OXFORD, MA
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Pair

Wed Sep 18, 2013 12:59 pm

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Around 150 mm Nakiri
Around 200 mm Gyuto


These are 154-CM an excellent stainless steel. I was thinking about trying out a Urasuki grind on these.

I have been playing with this basic handle shape on a dozen or so knives now and gotta say it is extremely comfortable :)
Last edited by timos on Wed Sep 18, 2013 2:02 pm, edited 1 time in total.

Re: Pair

Wed Sep 18, 2013 1:16 pm

Santoku?? I'm assuming the pencil outline on the Nakiri looking knife still has to be cut out.

Re: Pair

Wed Sep 18, 2013 2:01 pm

Ahh yes let me fix that CanadianMan that should be called small Nakiri. I am still learning all these wonderful names and shapes. Thanks for the correction :)

Re: Pair

Thu Sep 19, 2013 2:45 pm

TIM <> Are you proposing a double-bevel Gyuto w/urasuki grinds on both sides?

If you are proposing a single-bevel gyuto with urasuki on the back side, I would suggest against it. I have used a very well made example of one, and honestly, the single-bevel steering is horrendous on a Gyuto.

Re: Pair

Thu Sep 19, 2013 3:41 pm

I am glad you spoke up about the single-bevel gyuto with urasuki on the back side. That is what I was thinking.

How about a 36" radius bevel on both sides to achieve a 50/50 edge. With the edges zero ground and bit of convexing in final sharpening. The bevel would follow the contour of the edge resulting in a distal taper beginning at about 170mm from the tip. This will result in an extremely thin blade. About .005 behind the edge and only .015 thick at about 1/2" from the edge. It is much easier to do this in stainless than in carbon steel. My only concern for this type of edge is if you hit anything hard the edge can tend to chip out in rather large size at RC 60-62. At a softer RC 58-60 the edge flex more and chip less but requires more sharpening.
I guess then my question would be for very thin edges is it preferable for harder longer lasting sharpness with increase of chance of chipping?

Re: Pair

Thu Sep 19, 2013 4:11 pm

TIM <> Honestly, I'm lost a bit following your description. Your bevel off a 3' radius sounds like a hollow-grind, and if it's a hollow grind, I don't see how a zero-grind edge is possible.

Irrespective of that, I don't think I've ever experienced a laser thin edge on soft steel; nor do I think think it could support a keen enough edge w/o fallout. I've dealt with plenty of thin edges generated from super acute final bevels on laser thin hard steel blades. Caution due to chipping is just something you have to accept if you're using such a thin edge. I don't know I'd do it on a Gyuto; maybe on a Sujihiki, but I do know I prefer my Gyutos in the Hrc61-63 range.

Re: Pair

Thu Sep 19, 2013 5:29 pm

Here is a more detail of what I am proposing. dimension in mm and inch
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Melampus,

Yes the 36" radius is hollow grind technically but much closer to being a flat grind than typical hollow grind of 8 or 10" diameter. I like it b/c it mimics old school large diameter wheels.
As for zero grind, perhaps it means the same to me for either hollow and flat in process only(to grind both sides till coincident at edge). I am very ignorant to the correct terms of the knife so i appreciate the patience with me. (I did just watch the videos in FAQ section). So perhaps its better of me to post photos only then someone else can say what it should be called. lol! Ok, I am learning very much! thanks for your participation:)

-Tim

Re: Pair

Fri Sep 20, 2013 12:23 am

TIM <> As far as I know, a zero-grind edge is a straight grind from spine to edge. It doesn't have to be a flat grind; there can be some convexity, but point is no distinct bevels between spine & edge. From your illustration, I can see how you mean a zero-edge, but with a 3' wheel on the edge, I would think the final bevel would be concave... though I guess the large wheel doesn't really impart a radius. Nonetheless, your spine looks to be @2.54mm, and then half the distance to the edge you have worked down to 2.02mm. Your next marker a quarter of the way towards the edge references the 36" wheel, but I'm ignorant as to the 914.40 marker. The next marker dictates a final included angle of 20 degrees at the edge leaving a .13mm thin edge measured .73mm up from the edge of the edge.

I honestly don't have calipers/micrometers to compare these numbers to edges that I am familiar with so I'm sorry I can't add much more by way of experiential opinion.

Re: Pair

Sun Sep 22, 2013 6:49 pm

Quick pic of the rough beveling on the Gyuto
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The way this is turning out I will bring the grind right up to the spine this will leave a little less than 1/16th thick steel halfway across the width.

Melampus for some scale those are a 5° bevel on either side at the edge. This is applied to the edge when it is about the thickness of a hair. Basically a convex edge with a "slightly" hollow, "mostly" flat grind :) I am shooting for a gradual distal taper along the full length of the blade.
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