Japanese edge tools on grinders - not good right?

[Sam Murdoch]

I have been able to keep my Japanese chisels nicely sharp with my water stones over the past few years. (Up until then I was mostly using German or American edge tools kept sharp with oilstones and an assortment of very succesful grinding techniques.)

My Japanese chisels have never needed more serious attention than I gave them on the water stones, but I was recently chopping into some ebony and now one of my chisels is showing a pretty jagged edge.

Seems to me that I have read here and elsewhere that grinding Japanese edge tools on a wheel is not a good idea because of the development of the hollow grind. I have an old Tormek 2000 and a hand crank 6 in grinder. Should these not be used on my kanna blade and my chisels?

Still on the learning curve here and appreciate any insights.

[David Weaver]

They will be fine on the tormek, that's what I'd use.

I've ground them on a high speed grinder, but you have to be mindful that the temper temperature for the very hard white steel tools is around 275 degrees and the edges depend more on the wrought iron for support (which exits more the smaller the wheel). Plus, it makes for an unsightly chisel.

My favorite way to correct the edge on a japanese chisel that needs a lot of removal is one of the old sloppy friable coarse stones.

[Christian Castillo]

The Tormek is water cooled, you're totally safe, heck, I doubt there are many tools better suited for cool grinding of Japanese tools than the tormek.

[David Weaver]

By the way, add a tiny hairline sized microbevel of 35 degrees or so the next time you chop into ebony. Most chisels aren't up to it at anything less.

[Sam Murdoch]

Thanks for the feedback/advice.

[Roger Nair]

The Makita flatstone wet grinder is well suited for the task.

[Jack Curtis]

...My Japanese chisels have never needed more serious attention than I gave them on the water stones, but I was recently chopping into some ebony and now one of my chisels is showing a pretty jagged edge.

Seems to me that I have read here and elsewhere that grinding Japanese edge tools on a wheel is not a good idea because of the development of the hollow grind. I have an old Tormek 2000 and a hand crank 6 in grinder. Should these not be used on my kanna blade and my chisels?...

I might use a grinder to smooth out the chipped edge, but that would be with edge straight to the wheel, not at an angle so that you'd be grinding the bevel. Then I'd use the waterstones to remake the bevel and back. Now this may require a little tapping out to reestablish the back, depends on how deep the chips. Also, this is a bit tricky for the chisel, but straightforward for the kanna.

I have a Makita horizontal water grinder for exactly this situation, or that's what tilted me to the buy decision. I use the Makita for many other grinding tasks when I have no desire to create a hollow.