Tormek Community Forum

In the Shop => Knife Sharpening => Topic started by: Ripper7620 on September 28, 2019, 02:54:05 AM

Title: Is it ok to sharpen traditional Japanese knives on the T-8?
Post by: Ripper7620 on September 28, 2019, 02:54:05 AM
(https://storage.googleapis.com/stateless-shop-echefknife-com/2017/09/455f72d7-saskinr_main.jpg)I'm getting a high end Japanese kitchen knife in the future, and I was just wondering if it would be a bad idea to sharpen it on the T-8? I've seen it done before, but not for a high carbon steel one like the one I'm saving up for. Here's the knife in question;
https://echefknife.com/product/yoshihiro-kurouchi-super-blue-steel-stainless-clad-kiritsuke-multipurpose-chef-knife/

Thank you for any, and all replies.
Title: Re: Is it ok to sharpen traditional Japanese knives on the T-8?
Post by: Jan on September 28, 2019, 11:04:45 AM
As you surely know the best way to maintain the sharpness of a knife, made off Super Blue High Carbon Steel, is a water whetstone. #1000 grit for the first stage and #3000 to 10000 grit for finishing.

If the hollow grind is acceptable for you, you can use Tormek.

Blue High Carbon Steel contains tungsten carbides which are less hard than AL2O3 abrasive in the SG stone. Nevertheless your Super Blue High Carbon Steel has added vanadium for wear resistance. Vanadium carbides are slightly harder than AL2O3 abrasive. For this reason you may have difficulties to sharpen this steel with SG stone. The SG stone abrades the steel matrix but the vanadium carbides will protrude from the matrix. The Tormek Extra fine diamond wheel will cut the vanadium carbides without any difficulties. For finishing the edge the Japanese water stone with a #4000 grit may be used.

Jan
Title: Re: Is it ok to sharpen traditional Japanese knives on the T-8?
Post by: Ripper7620 on September 28, 2019, 08:21:54 PM
Thank you very much for the detailed reply, I appreciate it. I should have guessed that a traditional stone process would have been more appropriate for a traditional Japanese knife.
Title: Re: Is it ok to sharpen traditional Japanese knives on the T-8?
Post by: John_B on September 28, 2019, 11:29:48 PM
I think this is a traditionally shaped Japanese knife using a newer Super Blue Steel. This is a rather new exotic steel. It is not at all easy to sharpen with the traditional Japanese stones due to the Vanadium. I think you may have an easier time getting a proper edge with the fine diamond wheel.
Title: Re: Is it ok to sharpen traditional Japanese knives on the T-8?
Post by: Ripper7620 on September 29, 2019, 07:02:29 AM
Thank you for the reply, I appreciate you taking the time. Honestly from what I've heard about high rockwell rated knives is that diamond stone, even the finer grits, put significant scratching on the edge, so I'm a little scared to try it out on a $300 knife.
Title: Re: Is it ok to sharpen traditional Japanese knives on the T-8?
Post by: Jan on September 29, 2019, 10:52:01 AM
The grit of a new diamond wheel is very sharp and aggressive and can scratch the edge. The diamond wheel should be after a break in period and you have to use very low pressure. The grit of the diamond wheel should be extra fine, e.g. Tormek DE-250.

Training with less expensive knife is highly recommended.

Jan

Title: Re: Is it ok to sharpen traditional Japanese knives on the T-8?
Post by: Ripper7620 on September 29, 2019, 02:05:53 PM
Thank you for the reply, I appreciate it, and amen on "iron sharpens iron".
Title: Re: Is it ok to sharpen traditional Japanese knives on the T-8?
Post by: plinth on November 11, 2019, 06:16:27 PM
Sorry for the late reply. I only sharpen my Japanese knives on my T8, but I do not have any super blue and my Masamoto is Hitachi White Number 2 so just very fine grain high carbon steel so no very hard elements to deal with.

My Myabi uses MC63 steel (an SG-2) which does have some Vanadium but it sharpens very nicely with the SG-250 and honed with three leather wheels on the FVB using the 4 micron, 1 micron and .25 micron compounds. Even in my inexperienced hands I get a BES score of under 100. My kasumi is really easy to get under 100 and the course SG-250 brings the bur up immediately.

It is interesting how your link describes the knife as a general purpose knife as it is unusual to see a kiritsuke described as such, it is more normally known as a slicer. A traditional chef's knife is a Gyutou and I use it for 95% of kitchen work. I guess it depends on whether you want it as a collector piece or as a tool. Mine are tools and my Masamoto has a patina and scratches but it is used every day and I keep it sharp.

What did you decide to do?
Title: Re: Is it ok to sharpen traditional Japanese knives on the T-8?
Post by: wootz on November 17, 2019, 04:14:56 AM
Al, New Zealand woodworker & sharpener - twice as sharp as the Gillette razor.
Sharpened on Tormek and honed on paper wheels, using our software

(http://knifegrinders.com.au/photos/Al_NZ_25BESS.jpeg)

Video how we sharpen Japanese single-bevel knives on Tormek: https://www.youtube.com/watch?v=dhpajIaBW0c (https://www.youtube.com/watch?v=dhpajIaBW0c)
Title: Re: Is it ok to sharpen traditional Japanese knives on the T-8?
Post by: Ken S on November 18, 2019, 04:30:37 AM
Another outstanding video, Wootz. Highly recommended!

Ken