I got lots of chips and they ain't potatoes.
- This topic has 11 replies, 5 voices, and was last updated 03/09/2018 at 10:28 am by
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This is the knife with the 6 degree per side bevel, right? Knives with high hardness steels and thin edge geometries are prone to chipping. I have chipped my gyuto by accidentally lightly tapping the edge against a plastic bowl. It is not inconceivable that cutting a really robust hunk of bread could do that to a delicate edge.
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This is the knife with the 6 degree per side bevel, right? Knives with high hardness steels and thin edge geometries are prone to chipping. I have chipped my gyuto by accidentally lightly tapping the edge against a plastic bowl. It is not inconceivable that cutting a really robust hunk of bread could do that to a delicate edge.
Yup, I’m coming to that conclusion. I think it’s a combination of the hard crust and the hardness of the board. The board is one of those thin sheets of a pressed hardboard, kind of like what we used to call masonite. The problem is probably the amount of force I apply as I try to cut through the bottom crust. Also, in making that final cut, the entire length of the blade is used. I’m going to switch to a much softer cutting board, maybe an end-grain checkerboard pattern from maple and walnut. I’ve got a drawer full of the black walnut pieces, given to me by someone I’d made a knife for long ago.
In repairing the damage to the Aritsugu, I filed the edge flat, removing the deepest chip recesses. I then changed the angle to 10.5 degrees and proceeded with the WEPS, starting at 200 and working my way up to 1500, then followed a progression of diamond films (6, 3, 1.5, 1.0 microns). I ended the job with a new set of cow leather strops, loaded with 1.0 micron paste. I’m sure that the 21 degree inclusive (10.5 dps) edge is somewhat less sharp than the original 12 degree inclusive (6 dps). I checked on a piece of telephone book paper and it passed with flying colors. Really, really, really sharp! What was also remarkable is that even with the need to reestablish the bevels, it took less than 45 minutes.
I worked the 200 grit only until the flat was quite narrow, maybe 0.25 mm. After that, I took each grit in sequence, applying at least 60 strokes per grit.
Hey Tom, in my experience, knives specified to cut bread have always been a serrated knife. That knife is incredibly thin edged. After a year of use that really didn’t appear unreasonable or an excessive amount of wear. From what you wrote and I read I was expecting much more pronounced chips and rolling. Under 50X it really wasn’t horrible. I can’t tell from the video just how thin the knife blade is but it appears to be very thin, thinner than your average chef’s knife. I’m sure you’ll be pleased with your wider angle. I would designate that knife for soft foods like fish or raw boneless meat and not hard crusty bread. I think that knife is mean to use as a drawing slice like a sushi knife not for push cutting hard foods. JMO
Marc
(MarcH's Rack-Its)I purchased this end grain cutting board made by Jones Cutting Boards LLC:
I have noticed a big boost in edge retention on my knives as a result. I still use polycarbonate boards for poultry prep, but just about everything else is done on that end grain board now.
Thanks for the reply Read… As you observed, trying to maintain the original bevel width would mean removing a lot of steel. The wide bevel isn’t actually a true, flat bevel. It’s more of a convex. In any case, using the Low Angle Adapter would only get me down to about eight degrees, which is what I put on my sister’s knife. I decided that the very low angle was too fragile for my purposes, so I went up to 10.5 dps. When I posted my original video of the factory’s edge, one of the members here responded that the knife didn’t belong in a kitchen. I had my doubts too, and had limited its use to tomatoes and such. When it became clear that my sister was using hers regularly, I started using mine on bread as well. Why? Because it cut bread better than any knife (serrated or otherwise) I had ever used.
Even a two-dps increase reduced the bevel width to no more than one millimeter. I’ll try to take a couple of micro-photos showing bevel width.
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The board is made of cherry in the 18 x 12 x 1.5 size. I purchased it from an authorized third party retailer (www.houzz.com) because it was a great deal ($94) and it was made by a reputable shop in the US. I actually wanted a walnut board because I thought I preferred the way they look but was pleasantly surprised about how lovely the cherry board was when it arrived. I hope to get another one at some point down the line.
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This discussion has accomplished – I think – what I set out to do, which was to find the cause or theorize around the chip damage. I’ve come to conclude that I had simply applied too much force to the blade edge as it came in contact with the cutting board(s). Even with such a sharp knife, cutting through the hard base crust of this bread took quite a bit of force.
My professional work exposed me to two types of cutting: slicing and bursting. Burst cutting is typical with thick substrates and is accomplished by displacing the material at the contact point. The edge actually compresses the material at the cut point before it “bursts” through. On disposable absorbents production machines, we cut the fibrous paper pulp and the compression provided by the cut operation served to “crimp” the material into discrete segments. We typically used a tool steel blade which was rectangular in cross section – about 2.5mm thick by about 40mm wide. The blade was clamped on a parent roll and allowed to flex as it when through the cutting part of its rotation. To be clear, the long dimension of the blade is cross-ways, relative to the cut. For thick materials like absorbent fluff, you’d actually hear the crack of the edge finally bursting through the material and hitting the anvil roll.
In my case here, I was doing something similar by applying pressure to the blade to get it to break through the bottom crust of the bread loaf. When it finally broke through, the edge would hit the board hard enough to fracture the very thin edge.
Thanks, Guys…
Thanks TC, great explanation! This really brings “purpose sharpening” for knives into a clearer view. Not only from a sharpening aspect, but from the cutting side of it as well. It’s important to use knives that are sharpened for a “purpose” for that purpose. For those I sharpen for I do my best to explain what each knife was sharpened to be capable of and in the case of kitchen knives that have at least 3 or 4 knives there should be one capable for anything faced in the kitchen. Knowing which knife to use in which circumstance makes edge retention a lot less of an issue for most knives at least from my own experience.
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