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Marko Tsourkan
05-29-2014, 10:08 AM
I am officially adding A2 to the list of steels that I am offering.

I have been revisiting A2 for a couple of years now, experimenting with heat treatment. I think I have finally arrived at a formula that results in characteristics I was trying to get all along - a good balance of sharpness, ease of sharpening, edge stability and edge retention.

The main benefits of the A2 are additional stain and wear resistance. In my opinion, A2 would makes a great line knife (as well as a bread knife and a scimitar) that doesn't need a lot of care, holds an edge considerably longer than most steels, and gets comparably sharp to 52100.

Another steel I am going to offer is powder stainless #2. This steel is great and I have had some great results heat treating it, but on the downside, it is quite expensive, so I haven't used a lot of it. I will offer it as custom orders, but will have to factor in the steel's cost into the overall price. The main difference between PM#2 and AEB-L is added wear resistance. Sharpness is comparable.

(Just in case if you wonder, PM#1 is related to PM#2 but is almost impossible to get. I have some of it, but I am saving it for san mai at some later time).

Von blewitt
05-29-2014, 10:15 AM
Sounds great Marko, A2 sounds like a great steel. I guess it must be to meet your standards.

Matus
05-29-2014, 10:23 AM
Marko, A2 got a lot of respect - also thanks to Yoshikane (SKD is supposed to be A2 if I am not mistaken). How do you expect your blades in A2 to compare to Yoshi?

I have and use Yoshikane SKD and SLD knives and really like their properties. Very though, good sharpness and edge holding and not that hard to sharpen (easier than AS in my opinion). De-burring is OK too.

So yes - this is a good news :)

Marko Tsourkan
05-29-2014, 10:41 AM
A2 is an interesting steel - it looks great on paper, but to arrive at a good heat treatment formula for a kitchen knife is not that easy. I kept revisiting this steel for years, and this is the first time I think I am happy with the outcome. I will need some more user feedback to make minute adjustments, but I think this is a very good starting point. I hope this will become one of my super steels akin 52100.

I sharpened my A2 knife on diamond and after 1K and felt strop loaded with 1Micron diamond, I was able to roughly shave hairs on my forearm. Burr formation and deburring was no issue at all.

The HT formula I am using results in a fine grain structure, so even at high hardness (63+RC), the edge seems to be stable and tough at an acute angle and thickness of under .005 inches.

Matus
05-29-2014, 11:14 AM
Thanks Marko, that does sound very, very good :)

Sam Cro
05-31-2014, 02:42 PM
Here is a site ( I have posted on here and a few others I frequent) that is very useful to anyone that makes knives click on the steel you wish to know more about and it even has the heat treating info for it .

http://www.hudsontoolsteel.com/site

Marko Tsourkan
07-29-2014, 09:19 AM
So I got my first feedback for A2 (new batch, new HT) come in and it have been positive. The blade takes a keen edge and, as expected, holds it pretty well. The pro user I asked to evaluate it, has used the blade for several days and hasn't needed to strop it yet (the knife still shaves and cuts paper towel).

I think this is a worthy contender to 52100 and with a proper HT, might even be a better steel (than 52100) in some respect. I am going to get some more feedback from other users, and will keep you posted.

I also think it's a great steel for a workhorse gyuto - edge retention, stain resistance, sharpness and toothy edge. Moreover, asymmetric geometry might be a better choice for a workhorse gyuto (slightly heavier than S grind), the only drawback might be that it is left or right-hand specific.

Marko

icanhaschzbrgr
07-29-2014, 09:40 AM
Great news Marko!
Can't wait for my custom order to happen :happy1:

Marko Tsourkan
08-02-2014, 11:23 AM
I got some feedback on my heat treatment of the A2 and results are very encouraging. Sharpness, edge stability is comparable to 52100, but edge retention is considerably better. One tester used the knife for a week and a half in a pro kitchen without touching up or stropping and when he finally stropped on felt with diamond, the edge came back about 90%. That's excellent given the length of time the knife was used. With stropping every other day or even every third day, the time between sharpening could be prolonged to 3-4 months (depends of course what you cut) in a pro kitchen, which will considerably prolong geometry and a life of the knife, making it a particularly good investment. Not to mention the joy of an owner who hates sharpening. :)

Also, after 10 days of use, the knife built up no patina on a 600 grit blade finish, and that made me worry that I might mixed up stainless with A2, but after some mustard testing, the blade was confirmed to be A2.

I am going to continue doing minute tweaks to HT, but the preliminary indicators are that this is another super steel if heat treated correctly.

M

ThEoRy
08-02-2014, 09:36 PM
Do Want!!

jai
08-03-2014, 03:11 AM
Not saying your wrong but I honestly could no ever imagine that a knife edge could be prolonged 3-4 months in a pro enviroment. After about the 4th time stropping it starts the get diminishing returns and needs a bit of steel removed just a touch to keep it really sharp. Maybe this steel is the answer to everything though but I guess it depends on what people think is sharp enough to use at work.

bear1889
08-03-2014, 07:18 PM
Marko explain the left or right specific grind. BTW the more I use my lottery 240 mm knife in 52100 the more amazed I am. Great knife thanks again Marko!

Marko Tsourkan
08-03-2014, 09:59 PM
Not saying your wrong but I honestly could no ever imagine that a knife edge could be prolonged 3-4 months in a pro enviroment. After about the 4th time stropping it starts the get diminishing returns and needs a bit of steel removed just a touch to keep it really sharp. Maybe this steel is the answer to everything though but I guess it depends on what people think is sharp enough to use at work.

Regular stropping on felt and diamond and occasional touch up on 8k diamond plate gets my 52100 through about 2 months in between sharpening in a pro kitchen. A2 has at least 30% more wear resistance, so I think it would not be unrealistic to expect the edge to last for 3+ months in between sharpening, with regular touch-ups on felt and 1M diamond and occasional touch up on the 8K plate. I admit, this is an estimate, but I don't think it's unrealistic one.

Now, we are talking about a working edge of 3-4K, not higher.

Choice of steel and a heat treatment tailored to maximize wear resistance while preserving edge stability is what accounts for the edge retention. I guess, the best way to convince you would have you try it yourself...

chefcomesback
08-03-2014, 10:14 PM
Regular stropping on felt and diamond and occasional touch up on 8k diamond plate gets my 52100 through about 2 months in between sharpening in a pro kitchen. A2 has at least 30% more wear resistance, so I think it would not be unrealistic to expect the edge to last for 3+ months in between sharpening, with regular touch-ups on felt and 1M diamond and occasional touch up on the 8K plate. I admit, this is an estimate, but I don't think it's unrealistic one.

Now, we are talking about a working edge of 3-4K, not higher.

Choice of steel and a heat treatment tailored to maximize wear resistance while preserving edge stability is what accounts for the edge retention. I guess, the best way to convince you would have you try it yourself...

Would love to try and give you a feedback if you have a blade laying around , just saying Marko :)


Sent from my iPhone using Kitchen Knife Forum

jai
08-03-2014, 10:30 PM
Haha id love to try aswell how much for an express suji. But on topic I guess it depends what your using your knife for and how many shifts you do with it per week. And what level of sharpness your satisfied with. But yeah feel free to prove your point by sending me a suji ill pay for it.

Marko Tsourkan
08-03-2014, 10:46 PM
Actually, the feedback (week and a half of pro kitchen use without stropping) came from an Aussie. I will continue picking his brain and report here. I got another knife in same steel out and will get out a few more, so there should be more feedback soon.

Unfortunately, I don't have capacity to make knives to send for pass around... Too far behind my custom work... I do, however, gather feedback on my first blades, and make changes for the subsequent blades. So far, I am pleased with the HT for the A2.


Folks are welcome to pass around their knives.

M