Rockwell & Blue Paper steel & White #2

"The Tanaka Sekiso series of knives by Tanaka features handmade custom knives that are hot forged with Damascus blades. The core blade is made from Hitachi Blue Paper Steel (HRC 60 and up)."

Above is an ad that I read. Rockwell 60 & up (not sure how far "up" that goes)

I read another ad for a White #2 (different maker) with a Rockwell of 61.

I was under the impression that White #2 was softer than blue Paper Steel.

Can someone clear that up for me, or direct me to the proper source?

Thanks,

dennis

Hardness is determined by the method of heat treatment, not the composition of the steel. Some steels get harder than others, but both white and blue steel can do 60-62 no problem. You can heat treat the same steel to a wide range of hardnesses*.

The difference between white and blue steels is that white steel has less alloying elements than blue steel. Both are very nice.






*is 'hardnesses' a word? I'm not sure it should be.

Dennis,

Hardness is a function of the heat treatment of a steel, not a particular steel.

Rick

The steels can be heat treated to a range of hardness. Some steels are easier than others to heat treat to a high hardness, either of the steels mentioned could easily be heat treated to 60-61 Rc. Many of the Japanese knives heat treated by eye in a forge can range in hardness because of the limitations of doing it by eye.

BurkeCutlery said:

*is 'hardnesses' a word? I'm not sure it should be.

Click to expand...

According to the Wiktionary it is: http://en.wiktionary.org/wiki/hardnesses#English

I would argue that the heat treatment of a given steel is determined by it's composition therefore chemistry is relevant.

I think in comparing steel it would be best to discuss in general terms. These two steels in general do not have the same hardness but two specific pieces of these steels could have the same hardness.

-AJ

dennis7490 said:

I was under the impression that White #2 was softer than blue Paper Steel.

Click to expand...

Many people feel that blue steel has greater edge retention than white steel whereas white steel takes a better edge. I don't think there is a huge difference to be honest, blue steel is generally more expensive though

Steels can be hardened in a range of Rockwells depending on the HT and tempering. Just because it is harder, doesn't always mean it's better! If the steel gets too brittle at the higher hardness, it wouldn't be as good performance wise if the edge chips. I do have a Fujiwara Terayasu Nakiri in White #1 that is reputed to be between 63 and 64 rockwell, but I have no way of knowing what it actually is w/o a tester!

I have one of those Tanaka Blue Sekiso's incoming as a 270mm gyuto I also have one of his Blue #2 Kurouchi Nakiri's that takes a very sick edge off of J Nats. I have a white #2 Tojiro Shirogami Nakiri, but I haven't sharpened it up fully yet. The Tanaka Blue #2 takes a very nice edge.

I have a couple Tanaka damascus blue blades...I would guess them to be much higher than 60hrc....

Is the Tanaka knife handle D shaped or octagonal? I'm debating between that knife, the Hitachi Blue Paper Steel (HRC 60 and up) and the Gesshin Ginga 210mm White #2 Wa-Gyuto from JKI...so far. Difference in price is the JKI is about $70 more expensive. As they say, I will forget the $70 down the road if the knife is great.

Any input is appreciated. NOTE: I prefer a D-shaped handle, but I think this can be easily changed out at a place like JKI.

Thanks,

Dennis

The Tanaka Kurouchi Blue #2 is an oval Wa handle. I don't know about the Sekiso Damascus yet.

I would lean towards the Gesshin Ginga myself since it would have better F&F I think because Jon has them round the spine and choils. People rave about them and I guess they are similar to Kono's geometry wise. I went with a Gesshin Ginga White #2 Wa Sujihiki after speaking with Jon about F&F, Heat Treatment, etc. Not sure about the Tanaka gyuto's, but my Nakiri was fairly rough around the edges No biggie, I have a few belt sanders to take care of that issue! That was also a Kurouchi knife, which seem to generally be a bit "rougher" or more rustic. Can't comment on the gyuto since I don't have it yet!

The Tanakas you are speaking of have oval handles, but upgrades are available; mine are ebony octagonal. I have found the fit and finish to be only average with entry level Tanakas. As you pay more, the quality also goes up. The R2 ironwoods are pretty flawless....

Ok, wanted to update you guys here! I ordered a 270 gyuto and the box said 270, but it has a 240mm blade. The seller offered to exchange it, but I fell in love with it and didn't want to send it back! The Tanaka Sekiso gyuto I got has a D shaped handle with buffalo horn ferrule. Spine is eased, but not rounded. Choil was cleaned up with a belt sander or wheel and was no where near rough, but a little burr was left on the blade side of the choil. A few minutes with some sandpaper/files and it will be sweet. Blade is a tad thicker than I was expecting, but has an awesome convex grind. Food releases very well from it, little to no wedging, feels great while cutting. Went through a bunch of veggies almost as good as my thin Nakiri! Much better F&F and handle than on the Kurouchi Nakiri I have from Tanaka. Very little flexing, blade was straight and the grinding was very even. I saw the pass around review and there was a blade warp noted and a lot of stiction on the pass around gyuto, but not on mine.

The kurouchi nakiri and the Sekiso Gyuto are almost night and day from eachother in terms of fit and finish, but they both are stupendous to cut with! The Nakiri is wickedly thin and takes a very fine edge. The Gyuto feels like a workhorse heft wise, but cuts incredibly smoothly and the little extra weight makes it easier to cut with. OOTB edge was the best I have seen so far and sticks into my cutting board still!