japanese chisel sharpening questions

[ryanarcher]

why can japanese chisels never have a hollow ground bevel, or secondary bevel? I realise that the high carbon cutting edge is typically about rockwell 64+ and therefore very brittle, but can a hollow grind make that much difference in strength?

also, I've been lapping the back of my japanese chisels to keep the concave area away from the cutting edge, but this takes a while. I've heard of a technique of "tapping out" the hollow by striking the top of the chisel with a hammer. does anyone have any experience with this?

Thanks Guys! :)

Have a great one!
-ryan

[derekcohen]

Ryan

The hard steel laminated layer is not that thick. A secondary bevel or a hollow grind will likely remove it (and weaken the blade). The soft steel is easy to cut through, and so Japanese chisels are relatively quick to sharpen in spite of having such a hard steel section. In a sense, when you sharpen them, it is as though you are sharpening a secondary bevel all the time (if this makes sense).

You do not tap out the hollows on the chisels. It is unnecessary (on the plade blades you will). Every time you hone off the wire edge you will remove just enough steel to keep the hollow away from the blade's cutting edge. Don't get paranoid - there will be enough steel.

Regards from Perth

Derek