Exposing the core

[Peter Nowlan]

I forgot how to insert photos. You should see the knife I received yesterday, in ten years it’s the worst.
I had to completely remove metal from the edge right up
to the lamination line so there is no visible core steel visible.

I find the removal of the Jigane to restore the aesthetics and also ensure that the Hagane is actually the new Edge to be the most difficult aspect of knife sharpening. It seems to take an eternity to grind through that outer layer of softer steel

I’m curious as to how long it typically takes. For me it’s about 1.5 hours of work on coarse stones.

[branwell]

I've made a lot of knives over the years, have a full forge, 2x72 belt grinders, and like to collect and use water stones. Coming from that perspective....

What you are describing shouldn't take more than 35 minutes or so using hand tools.

What I would do if I where you is start with the blade clamped to a suitable surface and then use 80 grit sand paper on a firm backing to do your grinding. I've tried Atoma 140's and Nubatama 150's for this and they are too slow. On top of that, you have to keep stoping to check your work, stone maintenance etc. Automotive sand paper is the best for this. You can get sticky back rolls and it works great.
If you don't like working with sandpaper, I would start at 80 grit or so, then 120, 220, 320, 400, 600 and transition at that point to stones to get the finish you are after. If you don't mind paper, run it up to 1500 and transition at that point to the stones.

Tip for seeing the core. A little Ferric Chloride will instantly show contrast between the core and cladding. If you don't do it often enough to justify getting Ferric, you can use a Lemmon or other acidic food to create contrast. Might take a little longer but it works.

[Peter Nowlan]

Thank you. I’ve done this several times I was just curious how long other people take. I use coarse stones starting at 120 grit. 35 minutes is unrealistic for me. It’s typically one to two hours from start to finish in the repair work, thinning and sharpening. Good tip on the lemon. Thanks again

[ken123]

You sound like you are in need of a 46 grit diamond plate ...

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Ken

[gladius]

I forgot how to insert photos. You should see the knife I received yesterday, in ten years it’s the worst.
I had to completely remove metal from the edge right up
to the lamination line so there is no visible core steel visible.

I find the removal of the Jigane to restore the aesthetics and also ensure that the Hagane is actually the new Edge to be the most difficult aspect of knife sharpening. It seems to take an eternity to grind through that outer layer of softer steel

I’m curious as to how long it typically takes. For me it’s about 1.5 hours of work on coarse stones.

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It can be laborious and time consuming. Try Ceramic and Zirconia belts cut to size for hand sanding blocks or on blocks placed in a stone holder, that will give you control.

https://www.redlabelabrasives.com/

[Peter Nowlan]

Thanks all. I don’t need anything was just asking about time.
I’m done.

[ken123]

Thanks all. I don’t need anything was just asking about time.
I’m done.

... Just looking at it from a TVM (Time Value Money) perspective. Coarser grits = less time spent on a repair. Now that 46 grit plate does leave deep scratches so you have to look at that side too. Use the 140 Atoma to clean it up to a workable pattern. I also have a 60 grit plate but they both initially look quite similar.

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Ken

[branwell]

Gladius,

I've always wondered about cutting up a belt and trying that.

My fear was that the low grit belts are a bit dodgy from an evenness perspective until you have run them a litte. After that I, perhaps incorrectly, assumed that the abrasive would be too dull to work well by hand.

Will def give that a try. Ty for the tip.

[gladius]

Gladius,

I've always wondered about cutting up a belt and trying that.

My fear was that the low grit belts are a bit dodgy from an evenness perspective until you have run them a litte. After that I, perhaps incorrectly, assumed that the abrasive would be too dull to work well by hand.

Will def give that a try. Ty for the tip.

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No different than diamond plates; Zirconia being synthetic. The beauty is you control the pressure which is key to use. It has worked well for me over the years and cost effective. Low grit stones wear too quickly, then costly to keep flat having to buy even lower grit stones, etc.

[ken123]

Of course ymmv. I found lapping plates hold up better than belts of all sorts. Indeed belt failures happen relatively fast. Ceramic belts seem a bit more robust but marginally so.

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Ken

[Peter Nowlan]

I appreciate the reply’s. Believe me Ken if you lived in Canada I’d own several of those stones. The work took me about 90 minutes in total using a boatload of different stones. I exposed the core in 60 min . The knife has a very strange bend in it that hampered the process. It was a Dojo and I think the knife came with the bend/warp. Great learning experience though. The photos are on my IG account. PeterNowlan

[ken123]

I'll have to move
Those knife bends partially sharpened can be a mess to straighten out and sharpen.
Ken

[atang]

That’s rough Peter. Sounds like you prevailed Bent knives are such a headache sometimes.
I really like the nubatama 60grit. Really fast without the diamonds gouge, leaving less clean up work. Had to get the 46 grit plate to work up some mud first. Finished a hearty CCK edge re-profile and thinned (but not finished) in about 75 minutes. Not a bone crusher, but fairly thick for veggies. No cladding... looks like a mono steel
Anyways, the TVM Ken mentions has always thrown me for a loop. Quite interesting to see how much time people expect to put into a knife vs. how much time is actually spent on it and where the bottom line is drawn. Thanks!

[cliff]

I have been meaning to start a new thread about a new stone, a Nubatama 220, which I've been using to thin and fix some friends damaged knives. It's taking me awhile to get the feel for it. In its own terms, it's a fantastic stone: cuts quickly, doesn't dish or load too fast. It has worked especially well for dealing with a mangled Deba and putting an edge on a friend's knife that hadn't had one in far too long.

In this context, for thinning, even on an iron clad knife, it's taking me quite awhile. That is a virtue in that it keeps me from messing up too badly (I hope). But it is frustratingly slow for what I would call real thinning, more than the usual maintenance behind the edge. I've also been working on some Kanehide TK's. I love the steel but not the grinds. There too, I finally broke down and went to diamond plates to get things moving. The Nubatama did take those gouges out quite nicely.

[ken123]

Well this is a bit premature but I will be coming out with a new 150 grit stone - a Nubatama Platinum 150. The qualities of a platinum - slow wearing but fast cutting. Should fit this spot very well. Ill formally announce it when it comes in. Should work well on roughed up debas Of course there's still the 24 grit Nubatama and the 46 and 60 grit diamond plates for the right tasks.

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Ken

[cliff]

Is there something to use on these stones when they load, short of a diamond lapping plate?

[Peter Nowlan]

Atang I don’t really care how long it takes me to accomplish a task. 90 minutes converts to me being a better sharpener by completing 90 minutes or work. If someone else can do the same job in 45 minutes they either have more coarse stones, a nice belt grinder with all the right belts or they they are just more skilled than I am which is probably the case. I don’t sweat this work because it only takes me about 15 minutes to get the knife to a state where in most cases the customer will be happy. I need to spend the extra time to make me happy and tobhe 100% satisfied will take an eternity.

[ken123]

Is there something to use on these stones when they load, short of a diamond lapping plate?

Three things:
A diamond lapping plate. Typically a 140 or 150 plàte will do. This is usually a fast procedure. The 60 grit is faster but may be a bit much.

More water. This reduces swarf buildup.

Coarse cbn will will also remove swarf. Use a coarse grit like 80 micron. This works well on Shapton glassstones.

Note that you may still need to flatten with a plate. Also note that some black swarf in the stones doesnt affect the Stone's capability.

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Ken

[cliff]

Great, thanks! Should've thought of the Atoma 140 -- sounds like the best option at hand for the build-up I've encountered.