Sharpening a well-worn chisel

[derekcohen]

Thanks Harvey. There are varying views on sharpening Japanese chisels.

The traditional way is to hone a flat bevel. A hollow grind is considered negatively as it is believed by many to remove the support behind the hard cutting layer and so weaken the bevel. I do not believe this having hollow ground some if the cheaper bench chisels (nomi) over many years. Jim Krenov used to add a secondary bevel as well.

I believe that the real reason is probably that the bevel just looks nicer with the laminations standing out, hard steel against soft iron, and on the more expensive chisels this can be quite beautiful.

Here are three different types I own. Kiyohisa slick (paring) and bench chisels (white paper steel) along with a PM-HSS bench chisel.

The Kiyohisa are very special, even if they do not look fancy. No longer available, and when they were there was a 6 year waiting list.

Note that the slicks are only pushed and never struck with a hammer (gennou). The bevel is 25 degrees. Bench chisels are generally at 30 degrees. I try and use these chisels in the traditional manner, and only sharpen with waterstones. In my case, Shapton Pro 1000, and Sigma 6000 and 13000.

Somewhere here are Koyamaichi dovetail chisels as well.

Bench chisels are designed to be used with a hammer (gennou), hence the hoops to reinforce the handle. This creates a tool with great precision.

To the OP: I recommend that you do some research on the use of Japanese tools and chisels before going any further. Be patient

Regards from Perth

Derek

 

[Jiggy Joiner]

I think the OP is asking what happens, which could be sooner or later, when the hollow is reached when honing the bevel, I think?

I cannot remember the Japanese term for the hollow, “Uri” maybe?
Anyway, if/when the hollow is reached at the bevel, the hollow needs bringing back some.
This can be done with a ball pein hammer and anvil, or similar. The chisel needs to be upright, (bevel at top, and hollow underneath) then the bevel needs to be carefully/skilfully beaten with the ball pein or similar hammer. Done properly, this will strengthen the hollow, and give some more meat up front, to re hone the bevel.

A lot depends on the amount of use and honing the chisels receive. My Japanese chisels are respectful but, not top end in the world of Japanese steel and blades but, they get used regularly, and hold a nice edge for a good while.

 

[derekcohen]

For the final word on Japanese blades, read Stanley Covington's blog. Stan has lived in Japan for many years and lives and breaths woodworking ...
https://covingtonandsons.com/about-covington-and-sons-tools/

On chisels ...
https://covingtonandsons.com/tag/sharpening-japanese-chisels/

On preparing the back of the blade, the hollow (indeed, the ura, not a scollop) ...
https://covingtonandsons.com/2019/10/04/sharpening-part-10-the-ura-浦/

Regards from Perth

Derek

 

[Jiggy Joiner]

Great links Derek, I’m not too shabby when honing but, always ready to learn, even at my age.
I keep promising myself some nice top end Japanese chisels but, in honesty my modest grade collection has done me proud over the years.

 

[RKA]

I misread the OP and thought the chisels he inherited were already ground past the scallop on the back.  Upon re-reading, he says “almost” to the scallop.  There is a big difference.  Ryan, sorry about that.  Derek is right, if it’s close to the scallop, it’s fine.  Take some time to read up on Japanese chisels and give them a go.  If you have a question about a particular chisel that may have been improperly sharpened, post a picture of the actual chisel (front and back) close up so we can give you better advice.