Any advice on how to sharpen for durability / long-edge life?

[yoyoma]

Background:

• I'm relatively new to knife sharpening (have sharpened maybe 5 times total).
• I have all the stones and equipment needed for sharpening. 400, 1000, 2000, 4000, 8000 stones, and the flattening stone and nigura stone.

The situation:

I've gifted this knife to a couple : Haruyuki Mugi Santoku 180mm

They seem to get it dull or chipped after a very short period, even 2-3 months. They are home cooks and don't use the knife heavily, and they use it on a plastic board and have very basic knife skills. Their knife skills probably lead them to be hard on the knife, but that's not something I can change. Note that when I saw "dull" I mean dull - like non-knife person even notices it.

I'm the one who sharpens the knife for them, but I want to know if there is a way I can sharpen it differently so as to make the knife more resistant to chips and able to hold it's sharp edge longer. I'm willing to trade off high sharpness for longer-term medium sharpness.

From what I understand, to achieve my goals I should be sharpening at a higher angle than normal to make the knife stronger and hold it's edge longer (even though the initial sharpness will be less), like 30 degrees.

Does that make sense? Is 30 degrees too much or too little? Should I be doing anything else differently?

Open to suggestions.

 

[HumbleHomeCook]

Not much you can do to make a meaningful difference in those conditions. I mean, 2-3mos for abused AUS8 isn't bad. I'd sharpen as normal then cant up a few degrees and make a couple light strikes per side. I also wouldn't sharpen past 1k and probably would just stop on the 400 in those conditions.

 

[Rangen]

These are Guernsey people who have been handed a gazelle. Wusthof and the like know what they are doing when they sell people thick knives of soft steel. I am really not trying to disparage them; it's a question of matching the knife to the user.

You can't turn a near-laser into a soft-steel workhorse, but I think your plan is the next best thing, a nice fat angle to resist the chips. I sharpen my Chinese cleavers to 25 degrees per side, because they get whacked into the board. So I'd certainly go to at least that. No experience with 30 degree edges, but it does not sound like an unreasonable plan to me.

That said, if I used one knife all the time, I'd be sharpening it a lot sooner than every 2-3 months. So the part that seems like a problem to solve is the chips, not the longevity.

 

[HumbleHomeCook]

30dps is chopper territory and probably the outer limits of that. Go much steeper and you're just going to be returning a cleaned-up dull knife.

 

[Nemo]

As has been previously suggested, it's not that surprising that an Aus8 knife is pretty dull, after 2-3 months.

The chipping is a little more concerning. IDK whether this is from what they are cutting (hard stuff like bone, frozen food) or if the plastic board is responsible. Alternatively, they may be walk-chopping. Where on the edge are the chips? How deep are they? Got a photo?

If you want to improve your edge durability, the first thing to concentrate on is probably burr control. This encompasses both burr reduction and subsequent deburring. It would be interesting to see the knife after a few days or a week of use. This will tell you whether your burr control is problematic.

Can you describe how you deburr?

 

[mpier]

I’m not to familiar with Aus8 but you might try putting a micro bevel on it.

 

[Blank Blades.]

More polished edges should theoretically lead to less likely hood of chipping happening. Since deeper scratches on an edge basically act as initiation points for failure to begin.

Not saying this will lead to the knife not chipping. Because a hard thin knife will still chip if its abused no matter what the edge is like. But it just theoretically could lead to it not happening as easily.

As others mentioned. 2-3 months seems like its not really abnormal for a knife to go dull. Really its pretty decent depending on how often the knife is used in that time.