My ZDP189 Higo blade was “chipping” today (!!!) quite badly on the tip (Arrrrgh!!!). So I have decided to passe it gently on a Spyderco white ceramic rod before to strop it for a good hour on leather and compound.
Now it’s much sharper than before (!) and I know my edge is stronger with a little convexing which should prevent it from rolling…
Amazing grind ! Amazing steel !
ZDP-189 is very forgiving.
I don’t know how the chipping appeared as I did not use the knife hard (yet). I think it came from the very thin hard edge on the tip and perharps one fumble of mine.
Now it’s “cured” and fixed !
(I did not pictured it when it was a mess as I was much to concern about fixing it.
Perhaps the edge touch something hard I did not notice ?
I don’t know.
Notice how the “chipping” on the edge start to be erased by the ceramic shouldering.
now it’s all fixed:
The more I think about it (and when I see how I could fix it)
I think it was the very edge which rolled “chaotically” giving the look of a bad chipping but which could be fixed with a light sharpening (without removing matter)
The edge has touched something hard (it’s happen at the tip and this could have happen without me to notice it)
It happen once to me with another knife (mirror finish, thin and stainless) I was testing by cutting bambu and I completly ruined the edge: it was almost serrated after my ten cuts…. but I was able to realigned the edge and the damage was almost invisible after and the high sharpness restored.
My other ZDP-189 blade is the Chris Walker which is not as “smooth” sharp as the Higo but so far di not rool or chip. (It’s not as hard as the Higo-J though)
“The bottom of this blade edge is 30 degrees, and it’s continuously change to top of the blade.The top edge’s angle is 24 degrees.”
30 degree (15 by 15) with a very hard steel can be tricky when the edge is brend new.
Anyway I gently realigned the edge with white ceramique and strop it a lot.
I my have created a secondary (and stronger) edge, but the stropping should minimize its effect in pure sharpness loss.
Any knives are made to be used. It’s easy to hit something which alter the edge. A good tool should be able to withstand that, get fixed and ask for more.
The Higo-J, as an excellent tool, is no exception.
Bob Terzuola says: “If you knife is still sharp, it means you don’t use it enough !”
So let’s use it !
Researching the Rockstead site:
“We realized the best edge angle near the haft of the blade is 30 degrees and in the point of the blade 24 degrees.(We adjusted the angle to 30 degrees in the haft side because power was most concentrated there, which improved toughness, and 24 degrees at the tip of the blade, where power was low. The angle changes continuously.)”
Ok the angle at the tip is shallower (24°)… that’s why the tip is more fragile … Good to know.
The road so far:
“Rockstead Higo-J part I – A Folding Masamune in Paris”
“Rockstead Higo-J In the woods”
“Rockstead Higo-J: Part III – Masamune in Winter”
4 thoughts on “Rockstead Higo-J ZDP-189: fears and cures”