Japanese chisel modification?

[Christopher Charles]

Hello all,

I'll be building a series of small drawers for a tool chest over the next several months. I ordered a Japanese dovetail chisel from a favorite vendor and got a lemon--the chisel profile was noticeably asymmetrical, with one side 52 degrees and the other 60 degrees! It happens and a return will be no problem.

I'm considering modifying a Japanese bench chisel that I have rather than ordering a replacement. Anyone have experience filing/sanding the sides of a Japanese chisel? And then refinishing? I recall a recent thread on this subject, but I couldn't find the thread.


Thanks,
Chris

[Jessica de Boer]

I suppose it's possible as long as you don't introduce any heat that can ruin the cutting layer. There are some chemical blackening agents you could use to re-finish it I guess.

[Flamone LaChaud]

If you have a CBN wheel, it's easily done. Also Derek C has modified some of his to have nearly no side bevels at all - check out this section of his blog: http://www.inthewoodshop.com/ShopMadeTools/Soyouwanttomakeadovetailchisel.html

[Christopher Charles]

Thanks, that's my plan should I decide to go that route. Unfortunately, I'm fond of using a gennou and none of the western makers (e.g., LV or Blue Spruce) make a chisel with hoops.

Best,
Chris

[Flamone LaChaud]

That's true . . . . however once you buy it and like the chisel . . . the handle could be changed to be more in the Nomi method of use. Just sayin'

[Robert Hazelwood]

You won't be able to file the hard layer at the bottom, but you can use a file to waste away the soft layer if you like. I would use a belt grinder, but a grinding wheel or belt sander will work. I would use the coarsest belt or wheel you can find, and use a fresh belt or dress your grinding wheel really well...this is all to reduce the heat imparted to the steel. Assume that the temperature you need to stay under is about the boiling point of water. You'll need to work slowly and carefully, but it's not as perilous as grinding on the edge since there is more steel to serve as a heat sink. Of course if you have a CBN wheel, use that, since it grinds coolest of all from what I understand. But it can be done without. I have some dovetail chisels from Koyamaichi that came with small flats on the sides, more than I wanted, so I carefully took them down to a fine edge on a belt grinder with an 80 grit belt. Does not seem to have harmed the steel.

[brian zawatsky]

Chris,

Have you looked into Masashige ari nomi from Hida tool? Very reasonably priced, and good quality hard steel. The ari nomi have zero side lands, I bought them in 3mm and 4.5mm for cleaning up the corners of pin sockets.

[Christopher Charles]

Thanks Robert and Brian. Robert, the one I sent back was a Koyamaichi. Brian, I'll take a look and those might do the trick out of the box.