Explain Japanese chisels to me

[Botch]

 I don't have any Japanese chisels.  I do remember their ad copy from over 30 years ago in the old Garrett-Wade catalogs bragging up that the dished out backs of the blades allowed them to be flattened so much quicker than a western-style chisel, and I understand that.  What doesn't make sense to me are these two things:

1.  There's not much flat steel between the front of that dish-out and the cutting edge.  Once you've had to re-grind the primary bevel a few times (which I've had to do on a couple of my chisels already, and I'm just a hobbyist), the cutting edge will intersect that dishout, and the tool is no longer useable.  What am I missing here?  

2.  If you're paring with it, using the back to register flat for the cut, your workpiece needs to be at least as wide as the Japanese chisel, for those two "edges" to register to the board, and sometimes the workpiece isn't that wide.   Again, I would think a western-style would make more sense.     

Anyone?  

[Coop]

I agree with your logic. And why spend our money overseas. 

[wtnhighlander]

I watch a YT channel called "Woodworking Enthusiasts". Topics are all about Japanese traditional wood crafts of various types. Every such chisel I see there has a 1/4" or more of flat behind the edge, no matter how short the blade is worn down. I've seen them worn to within less than an inch of the socket / tang, always the same. I assume the user always re-flattens the back while sharpening, gradually wearing the steel thinner at the edge, thus leaving some hollow near the handle, but working the flat back up the blade along with the cutting bevel. Remember, that 'hollow' is only a few thou.

Maybe this hollow back makes the initial flattening go quicker, but it seems to me it would just be more work as the chisel is worn down.

[Tpt life]

I cannot find anyone tapping out chisels, but this guy mentions it, and demonstrates on a plane blade. 

 

[Ron Swanson Jr.]

On 7/31/2024 at 2:32 PM, Botch said:

 

1.  There's not much flat steel between the front of that dish-out and the cutting edge.  Once you've had to re-grind the primary bevel a few times (which I've had to do on a couple of my chisels already, and I'm just a hobbyist), the cutting edge will intersect that dishout, and the tool is no longer useable.  What am I missing here?  

 

Your right on with #1. This is a hollow dovetail chisel that came from the manufacturer like this. I should've returned it. You can see i don't have much sharpening that i can do in the future. 

Also, any speed advantage while flattening the back is negated if you use David Charlesworth's famous ruler trick, you can effectively flatten the back of any chisel or plane iron in about 1 min. 

But sometimes that hollow ground back can help with the chisel's balance. 

[drzaius]

Never use the ruler trick on a chisel. It's fine for a plane iron, but the back of a chisel needs to be dead flat.