Single vs. Multiple Hollow

[Josh Kandiko]

I'm in the market for a new set of japanese chisels and have noticed some come with one hollow and others with multiple. Is the multiple hollow chisel more durable than the single?

[Cliff Rohrabacher]

There is no reason to think that the geometry of the hollow on the back of a chisel will be an indicator of the quality of the steel or the heat treat process.

One time long ago - - - a very, very long time ago - - - the unique touches like how many hollows the back had or other conceits the smiths used would indeed be indicative of who made it. Knowing who made it would tell you all you needed to know about the tool.

[Mike Henderson]

Many Japanese chisels are hand made. Because of that, the maker often does things that are more "style" than function. Putting multiple hollows on small chisels may fall into that category.

On large chisels, my assumption is that a single hollow would go too deep (because of the curvature of the grinding wheel) so they put two or more to avoid that issue.

But overall, I agree with Cliff. It's not an indicator of quality.

Mike

[Wilbur Pan]

The only functional reason for the multiple hollows on Japanese chisels is so if you are using a wide chisel and a relatively narrow piece of stock, you will still be able to reference a cut off the back of the chisel from the multiple flats between the hollows. On a single hollow Japanese chisel, if it was wider than the stock, the hollow would make it a bit more difficult to reference your cut.

On the other hand, if a single hollow Japanese chisel was that wide, one could argue that you are using the wrong size chisel to begin with, and you should get a narrower one.

The depth of the hollow on the back of a Japanese chisel really isn't a factor, even on a very wide chisel. The deepest hollow that I have seen so far on a Japanese chisel is on the order of 1/64" to 1/32", which is nowhere near the thickness of the hard layer of steel in a Japanese chisel.

Me, I'm pretty happy with single hollow Japanese chisels.

[Josh Kandiko]

Thanks for explaining this! I just wasn't sure if there was something I was missing out on.