During my years of knife collecting and research I've seen and repaired quite a few damaged edges. So, when I was told that the Shun Elite SG-0403 Santoku I was about to receive for sharpening/repair and testing had really damaged edge, I was neither surprised nor concerned, I figured, I've seen it all. Except, when I I actually saw the blade, I couldn't decide what to call it. It was a jaw dropping experience, and not in a good way too. The tip was broken, about 4-5mm missing, and numerous chips and dents (predominantly chips) were covering the entire length of the edge. The blade looked quite uniformly serrated, except those were no factory serrations, but the result of the prolonged abuse. Well, needless to say, the blade was absolutely dull. I have never done broken tip repair of that size, but I've decided, my sharpening and grinding skills were up to the challenge, so I took the knife home, although I was scratching my head, thinking about the method and time I'd need to spend on bringing the Shun Elite santoku knife back to life. In the end, it all worked out superbly and I was very proud of the results :) Details below.
General- Shun elite series SG-0403 santoku is a fairly large knife for a santoku. It's pretty much as big as santokus get normally, 180mm(7") long blade. As far as performance and materials quality goes, Elite series are the best in Shun's kitchen knives. Even though the knife I received was abused in all sorts of ways, most of it was still in a good shape, and besides, I've seen quite a few Shun knives before, so most certainly the knife has very good build quality. Back then when I first reviewed the Shun classic DM0718 Santoku, I said the handle was quite thick and long, leaving relatively little knuckle clearance, compared to the other santoku knives I've handled. In that regard, Shun elite santoku has the classic model beat. The handle is even thicker, thus leaving even less knuckle space. I can't say my knuckles were hitting the board all the time, but when I used not so proper grip, I would touch the board with my knuckles. You can easily tell the difference comparing these two photos of the Shun Classic santoku and Shun elite santoku. Other than that, isn't a typical santoku knife, fairly thin for its size, you can see that on the Santoku review index page, and also relatively lightweight - just 200g, for a 7" long knife, with a handle that hefty, it's quite a feat actually, other santokus I've had were heavier, and I guess thin blade and perhaps handle construction contribute to that. Obviously it was few grams heavier out of the box, loosing the weight with the broken tip and then in repairs, when I had to grind away chips and portion of the spine to fix the damage.
Blade- The blade on the Shun Elite Santokus is 178mm(7") long, and about 46mm wide. I already mentioned its thin blade, about 2.3mm. For an average santoku it's thin, on the other hand, Shun classic santoku was a little thinner yet, 2mm. The blade is constructed using traditional Warikomi Awase style, where hard steel core hagane is sandwiched into the soft steel layers - jigane. In case of Shun SG0403 Elite Santoku, hagane is made out of the Takefu PM SG2 steel and the jigane is stainless SUS 410 steel. Unlike classic series, the cladding, or jigane is not pattern welded damascus steel, but just satin finished layer of steel. The line where cladding and core meet is quite well defined and I think adds to the looks of the knife. The SG2 core below that line is quite well polished, not just the bevels. Nice touch and good attention to detail. The factory edge on the Shun kitchen knives is 16° per side, or 32 ° inclusive angle. That holds true for all lines of Shun's kitchen knives, classic, elite, wasabi, etc. Theoretically, and practically, you could grind a thinner edge on 64HRC Powder Metallurgy steel, but given average western kitchen knife user habits, 16° per side is already a bold move ;) Besides, I suspect having different edge angles for different series of the same knives would make factory production more complicated. I don't know the details. On top of all that, SG2 steel, despite being high tech and all that, still doesn't have unquestionably positive reputation amongst the knife cognoscenti, I've seen very conflicting reports on its performance, although in my kitchen use the knife performed quite well. Definitely above VG-10 steel performance used in classic series. More about that in usage section. And to finish the blade description, I guess I have to mention the usual Shun/Kai cutlery logos on both sides and serial number and other markings on the left side.
Repairing The Blade- Well, it wasn't too easy, but wasn't difficult either, and in the end it worked out very well. As I said above, I've never had to repair the blade with the tip damage so extensive. Initially, after pondering a bit on the matter, I've decided to use the belt grinder, and grind the blade from both, edge and spine sides to forma new tip, but then after pondering a little more, I've figure, it was best to consult the master Dave Martell. Good thing about friends and asking advice when not sure what you're doing, it can prevent you from doing something silly, plus, perhaps prevent irreparable damage, and that's what I would've done. The right thing to do was to grind only the spine, gradually lowering it to make a new tip. By then, I was quite experienced with my belt grinder, so I was not worried about overheating the blade. Overall, the work took about 20 minutes, that included grinding the new tip and the edge, plus quite frequent coolings of the blade in the dihydrogen monoxide liquid solution, simply speaking, water ;) I've used 120 grit belt, followed by 45µm belt for the spine and the edge bevels. To polish the spine, I've used CrO loaded leather belt, but I wanted to sharpen the edge on the waterstones to get the better understanding of the SG2 steel and besides, I have better set of the stones compared to the belts.
Sharpening- Once the rough edge was formed, the sharpening procedure was quite easy. I've started with the 1200 grit King stone, few minutes with it, another 3-4 minutes on the 2000-3000 grit Aoto Natural Whetstone, then 5000 grit Naniwa Chosera, finishing stone section with 10000 grit Naniwa Chosera super finishing stone. Then as usual, stropping on the 0.5µm and 0.25µm diamond crystal loaded strops followed by stropping on plain leather strop was the finale. Given the edge condition, I've chosen 20° per side angle, to prevent such a severe damage in the future, although I did warn the owner that thicker edge would only do so much, and past certain point, the result would be the same chipping we had before. Dumping a knife into the kitchen sink full of other utensils and pots will do numbers on any blade, and high hardness knives like this poor elite santoku, take that sort of abuse not too well. Just check the edge damage photos above and in the gallery.
One aspect I do want to mention here. This was my second sharpening experience with SG2 steel. First time it was with the Shun Elite honesuki. I can't remember anything strange about sharpening that honesuki, and I can't find any records regarding sharpening in my old honesuki review notes either. Sharpening SG2 santoku was quite different. The steel wasn't too hard to grind, but it felt weird and I can't really place it why. Basically, even though I could quickly raise the burr and the edge took very nice polish, it felt rather rough than very sharp/aggressive fine type edge. Basic sharpness tests showed the edge was very sharp, but tactile feedback was different. To confirm my findings I've compared with other knives. Obviously, thick edges are different from thin ones, but edge sharpness and aggressiveness are still another matter. Basically, even though the polish was very good and the finishing grit was 0.25µm, the edge felt rougher than I expected. Not sure what caused this, difference in hardness with the first SG2 blade, or it felt strange because of the thick edge. Does cut well though.
Last updated - 01/17/12