TF Thinning Project

[yummycrackers]

Since a number of you have shared your TF trials and tribulations, I thought I would add my own. Back in the days of my youth and innocence (some two years ago), I thought it would be nice to try out TF's legendary heat treatment but being a broke graduate student all I managed to procure was a second-hand 210 nashiji gyuto off of BST. It came to me with a very nice cherry handle and saya but quite thick behind the edge and with a sharpened-off tip. I ended up using it a few times and then putting it aside in favour of other gyutos with the intention of eventually taking it to Ryan at District Cutlery for a general thinning. Long story short, I never ended up making it down to DC and decided to do it myself. I started out with a King 300 to fix the tip and even out the bevels, which had a number of low spots (don't ask me how long that took...) before taking it to a Nanohone 400, a King 1000 and finally a Nanohone 3000 to brighten up the hagane. Any and all suggestions are welcome for how to make it look even better or where to take it next. I don't use 210s very often nowadays so I don't know what I'll end up doing with it but I might play around with it some more before I'm done.

 

[yummycrackers]

As I got it:

 

[yummycrackers]

End-point after the Nanohone 3k:

 

[yummycrackers]

Now with some blue-ish patina:

 

[Choppin]

looks great! nice job. I would have started with a coarser stone (~200), would probably have saved you some time. anyway the King 300 is a solid stone, just takes a bit longer.

if it cuts well, I would probably call it done. but possible next steps would be:

1. taking the core steel to a mirror finish. Gesshin 6k resinoid is my choice, some people here swear by fine Naniwa Super stones (5k I think?)

2. you could also jump to naturals at this point. something like Aizu or Aoto and then Ohira suita. depends on what stones you have and how much $ are you willing to spend on new ones.

or do number 1. and then fingerstone the cladding. quickest way to a nice kasumi IMO

 

[Chicagohawkie]

Did the same thing with my nashiji, hours with a 120 shapton pro flattening and thinning. 10 hrs in and still not done. I’d start with a courser stone, but you’ll get there eventually, good luck.

 

[yummycrackers]

looks great! nice job. I would have started with a coarser stone (~200), would probably have saved you some time. anyway the King 300 is a solid stone, just takes a bit longer.

if it cuts well, I would probably call it done. but possible next steps would be:

1. taking the core steel to a mirror finish. Gesshin 6k resinoid is my choice, some people here swear by fine Naniwa Super stones (5k I think?)

2. you could also jump to naturals at this point. something like Aizu or Aoto and then Ohira suita. depends on what stones you have and how much $ are you willing to spend on new ones.

or do number 1. and then fingerstone the cladding. quickest way to a nice kasumi IMO

That's very helpful, thank you! The only reason I used the 300 was because I didn't feel like buying new stones if I could get away with ones I already had. But yes, it would have definitely made quicker work of it.

The finer stones I have at my disposal at the moment are a King 6k, a Kitayama 8k, and an Aiiwatani Asagi. Might either of those work for the core steel? The issue I encountered with higher grits is that they left scratches on the stainless cladding, which is why I went back to the 1k.

I would perhaps be willing to lay out for one softer jnat to obtain a nice kasumi finish, depending on the cost, of course. Alternatively, what would be the best place to procure some fingerstones?

 

[pavhav]

Alternatively, what would be the best place to procure some fingerstones?

Nice work. I have an Aiiwatani Asagi as well, but I can't recall using it with/on stainless cladding; it certainly does work well getting a mirror polish on carbon steels though. I got my finger stones from Jon at JKI; I don't believe he lists them on his site, but he he seems to occasionally have them if you contact him.

 

[yummycrackers]

Nice work. I have an Aiiwatani Asagi as well, but I can't recall using it with/on stainless cladding; it certainly does work well getting a mirror polish on carbon steels though. I got my finger stones from Jon at JKI; I don't believe he lists them on his site, but he he seems to occasionally have them if you contact him.

Great to know, thank you! Stupid question—when a stone (like the asagi) takes the core steel to a mirror polish, does the cladding end up all scratched up or just polished with no contrast?

 

[pavhav]

In my limited experience, all high-grit polishing tends to diminish contrast somewhat. To what extent depends on many factors i.e., the particular stone, pressure, slurry, core and cladding steels, etc.
The (soft, muddy) finger stones can help you increase the contrast after the polishing by allowing you to readily target the cladding while avoiding the polished core.

 

[Choppin]

The finer stones I have at my disposal at the moment are a King 6k, a Kitayama 8k, and an Aiiwatani Asagi. Might either of those work for the core steel? The issue I encountered with higher grits is that they left scratches on the stainless cladding, which is why I went back to the 1k.

I would perhaps be willing to lay out for one softer jnat to obtain a nice kasumi finish, depending on the cost, of course. Alternatively, what would be the best place to procure some fingerstones?

mmm I haven’t tried any of the fine stones you mentioned, but I suspect the Kitayama could achieve that? for sure someone here would know

one option is try and hit only the core steel with the fine stone. you can do that by raising the angle a bit instead of laying the bevels flat on the stone. or use the surface near the edges of the stone.

JNS also sells fingerstones, Kiita and Uchi versions. I found the Kiita to scratch some stainless claddings, not sure about the Uchi.

BTE many 6k synths, like the Gesshin, will leave visible scratches (fine ones, and if you polish in the same direction it leaves a nice finish IMO). it also leaves a bright finish that reveals remaining scratches from coarser stones.

the King 1000 (as other soft stones) on the other hand does a great job of masking scratches, leaving a dark, smoky cladding. so I guess that’s the effect you are seeing. maybe the fine stones are revealing scratches from coarser ones? how fine are the scratches when you use your fine stones?

 

[KenjiF]

Kitayama will leave a semi mirror on it. Here is my thinned man finished on kitayama (not soaked)

 

[yummycrackers]

After a few months of being away, I finally returned to this project yesterday. Here it is after my best attempt at a full progression: NH400, King 1K, NH 3K, King 6K, Kitayama 8K, iromono koppa from @ethompson
Turns out it's quite difficult to photograph these things. I believe the streaks are just from my fingers.

 

[yummycrackers]

Might be easier to see on video. All feedback welcome as always!

 

[JMeen]

Great job! I’ve got the same knife, but still untouched and not nearly as pretty as this one!

 

[yummycrackers]

Great job! I’ve got the same knife, but still untouched and not nearly as pretty as this one!

I'm secretly hoping I don't have to do another one of these anytime soon. But hey, if someone wants to gift me their denka, I'm happy to take care of it...