Hollow grinding japanese chisels

[Edwin Santos]

There is absolutely a risk that you will damage the chisel with the higher hardness white and swedish steels.

Hi Brian, could you be more specific? What kind of damage could occur by doing this on a Tormek wet grinder?

The various expert opinions here have convinced me to hone my japanese chisels by hand with a flat bevel, but I ask the question anyway out of sheer curiosity.
I believe my chisels are made from white#1 steel and I also have some made from blue steel. Thanks

[Brian Holcombe]

Basically one need separate the possibilities of damage in preparation from those of damage in use caused by the type of preparation. Super hard steels need support, if you take away their support than they run the risk of damage by absolute failure.

Damage in preparation can be mitigated by a wet grinder.

Damage in use cannot, the edge needs support as intended so that it won't be destroyed when you use it to the fullest capability of the chisel.

[Charles Guest]

Presumably one is missing the point when hollow grinding a tool that has traditionally been flat ground. If you want to use Western methods of tool preparation, then buy Western tools in the first place.

[Derek Cohen]

I will say again that one can hollow grind a Japanese chisel. I have done this for many years, and David Charlesworth has done this for a lot longer. Jim Krenov was another, by the way. However - and this is relevant - David and I have only ever used a water-cooled Tormek, Jim used a hand driven grinder, and in my case I have named the brand (Iyoroi), which is not one of the extremely hard steels mentioned by Brian. These chisels have not shown any edge weakness as a result of being hollow ground.

I am also not recommending that others should hollow grind their Japanese blades. I have a few Iyoroi, which I consider to be my beater chisels. Being “beaters” does not mean that they are abused, just that they are used outside the workshop, such as carpentry type tasks. They are hollow ground out of expediency. My good Japanese chisels are treated with reverence, and honed on the flat. I love the way this looks.

Regards from Perth

Derek

[Warren Mickley]

I will say again that one can hollow grind a Japanese chisel. I have done this for many years, and David Charlesworth has done this for a lot longer. .

Derek, it seems like just earlier this year you and David Charlesworth were singing the praises of A2 chisels. Was I fooled into thinking that what you actually use are A2 or PM VII chisels? Was David's A2 post just some sort of infomercial? Do you really use Japanese chisels in some significant way?

https://sawmillcreek.org/showthread....t=#post2900678

[Derek Cohen]

Warren, you add a little ... I would not say that I "sang the praise of A2" - I said that I did not find them the bogey man that many claim them to be. They sharpen up and work well enough for most users. In terms of steel and edge-holding, I have demonstrated that they are better than O1 but far behind White Steel and PM-V11.

Do I use Japanese chisels? How rude you are. Do you actually do woodwork? I can show that I have been using Koyamaichi chisels for nearly 2 decades. I think that I have had my Kiyohisa slicks for about a decade. My builds show their use over the years. Can you say the same?


Regards from Perth

Derek

[Charles Guest]

To the extent that hollow grinding a laminated chisel thins the softer steel behind the cutting edge then have not the desired characteristics of the chisel been compromised? It may make no difference in light paring, but certainly might if using a mallet or even the heel of one's hand.

[Derek Cohen]

Charles, I assume that you are speculating.


This was from an article on my website on morticing a hinge ...





Start by chopping 45-degree kerfs into the mortice. These kerfs will extend about half the depth, and stop about 2-3mm from the inside boundary line.





Use the wide chisel to pare away the waste. Stop short of the inside boundary.




Link: http://www.inthewoodshop.com/Furnitu...LidHinges.html

I have used these Iyoroi this way for many years.


Regards from Perth

Derek

[Charles Guest]

Though I own none, if I did, I'd rather defer to how expert Japanese craftsmen set up their meticulously crafted chisels. I think they deserve the benefit of the doubt, your very fine photos notwithstanding.

A flat ground Western chisel, un-laminated, is certainly nothing to sneeze at either especially with a grind of no more than 25* and hopefully a little less. Hollow grinding is a lovely expedient, but certainly not an absolute necessity, regardless of what tradition one chooses to follow.

[Doug Dawson]

Though I own none, if I did, I'd rather defer to how expert Japanese craftsmen set up their meticulously crafted chisels. I think they deserve the benefit of the doubt, your very fine photos notwithstanding.

A flat ground Western chisel, un-laminated, is certainly nothing to sneeze at either especially with a grind of no more than 25* and hopefully a little less. Hollow grinding is a lovely expedient, but certainly not an absolute necessity, regardless of what tradition one chooses to follow.

If a chisel can't handle the _very_ slight hollow grind from a Tormek T8, then it's not a very good chisel.

Too delicate to live, etc.

[Edwin Santos]

Presumably one is missing the point when hollow grinding a tool that has traditionally been flat ground. If you want to use Western methods of tool preparation, then buy Western tools in the first place.

Snarky response from one who admittedly owns no Japanese chisels.

[Edwin Santos]

Thanks for the responses and valuable perspective from several experienced Japanese tool users!

Looking forward to putting the new chisels to work and getting familiar with them. Cheers
Edwin

[Stewie Simpson]

Snarky response from one who admittedly owns no Japanese chisels.

Edwin; I also don't own any Japanese Chisels, but that doesn't impede my ability to read advise that warns against the use of hollow grinds on Japanese Chisels.

regards Stewie;

https://www.hidatool.com/image/data/...%20Chisels.pdf

[Derek Cohen]

Stewie, you and some others are reading what you want to see ... not what is actually written. The Hida article clearly states that one should not grind on a dry grinder because of the heat. And I would agree with this.

To repeat, my comment, along with that of Doug (above), made reference to the hollow created on a wet Tormek (with a 10” wheel), which is both cool and shallow. All this hollow does is remove enough cast iron to jig the bevel and reduce this area. It does not affect the hard cutting edge. I do not recommend dry grinding. Read that article again.

Regards from Perth

Derek

[Stewie Simpson]

Stewie, you and some others are reading what you want to see ... not what is actually written. The Hida article clearly states that one should not grind on a dry grinder because of the heat. And I would agree with this.

To repeat, my comment, along with that of Doug (above), made reference to the hollow created on a wet Tormek (with a 10” wheel), which is both cool and shallow. All this hollow does is remove enough cast iron to jig the bevel and reduce this area. It does not affect the hard cutting edge. I do not recommend dry grinding. Read that article again.

Regards from Perth

Derek

Derek; you warn "against reading what we want to see" and yet you chose to ignore the fact that the article by Hilda also covers the use of wet grinders,.

regards;