How is the hollow bottom of a Japanese chisel forged?

D

daily_grind

Joined
Apr 5, 2024
Messages
65
I'm not accomplished as a blacksmith enough to make one (yet?), only curious about how the hollow bottom of a Japanese chisel was made. I was hoping to find a video or a blog about it, or even a book. I was looking to try the hollow on a kiridashi style knife.

Cheers
 
Are you talking about a gouge? Or, the hollow grinds behind the sharp edge?
A photo would help.

A basic shape is forged and ground, then the hollow grinds are done on small grinding wheels. After HT they are refined again.
The steel is often san-mai or ni-mai, and only the bottom cutting edge hardens. The hollow grind creates a sharp edge that is easily touched up.
 
Last edited:
Thanks for the reply - Is there a way to resize images? Sorry this is so large. I am not looking to do two or three lobes of hollowness like shown, but rather one.
I guess it would make sense that the Japanese could use grinding wheels to make the hollow grinds.
I haven't yet tried forge welding, but I was planning on using mild steel for the top and something like 1084 or 1095 for the bottom? I might also try some white or blue paper steel, but I haven't studied them much.

hollowback.jpg
 
That is what I thought you were talking about.

You can use white/blue paper steel, but W2 will works just as good. For the non-hardening steel try 1018 (hardware store welding steel).

Those hollow grinds are done on small grinding wheels. If you have a steady hand, you could probably do them with a Dremel and a 1" Mizzy wheel. A 2" or 3" stone mounted on an arbor and chucked in the drill that is clamped in some sort of mount would also work.
 
If you have a small wheel attachment for your grinder that should work quite well.

The tool for the job is a small motor with a wheel attached. You can easily make one with a 1/4HP motor and a shaft adapter for the grinding wheel. Look this up on eBay and you will see something similar to what I am talking about:

Vintage Small Bench Grinder / Lathe for jewelry, metal working, hobby​

image link - https://i.ebayimg.com/images/g/Wf8AAOSwuSJiZZaN/s-l960.webp
 
It is a lot simpler than all that. Just get an abrasive wheel that is the diameter you want and chuck it in a hand drill. Clamp a 2X4 in the vise and strap the drill to a 2X4 with a large tie-wrap.
Amazon as well as your local hardware store have "Mounted Grinding Stone 1/4" shank" in many sizes and grits. They run about $5 For the small hollow grinds on a chisel a 1" to 2" stone would be right.


1717495548474.png

When I was young, every hardware store sold a little saddle stand that a hand drill would sit on. It had a large plastic or metal hose clamp to strap the drill down. You screwed the saddle to the work bench and when you needed to do a little grinding you strapped down your trusty corded hand drill and chucked the stone, buffing wheel, strop, etc. in the drill. I had to hunt a lot to find one on Amazon. It is called a drill mount. As you can see, it isn't much fancier than the 2X4 and tie-wrap I described earlier.
1717496035131.png1717496035131.png
 
Last edited:
I agree about not using a drill press. A friend of my fathers ruined a drill press like that.

I have a very large hand drill mounted into a stand that is supposed to turn it into a drill press. It was being scrapped. So I got lucky. Anyway it gets used for stuff like this. Usually with simple drum sanders chucked into it.
 
This is the modern equivalent of what I have. Google “drill press adapter for hand drill” IMG_7026.jpeg

Used Corded electric drills are easy to get.
 
You must log in or register to reply here.
Back
Top