Chris Griggs
08-14-2011, 12:46 PM
Okay, first a little back story. A while a back I bought a used set of AI butt chisels that came to me in pretty rough shape (see thread with angry rant here: http://www.sawmillcreek.org/showthread.php?161001-Dubbed-Chisels-I-am-so-very-frustrated&highlight=)
Since getting them I fixed most of the issues which mainly involved lapping the backs like crazy and grinding past the areas that were back beveled/dubbed. Additionally, The older AI chisels didn't have side walls ground as narrow as they do now, so I also ground down the side bevels to make these more ideal for chopping dovetails.
However, this past week I noticed that the about 1/16-1/8 of the edge/corner of the 3/8 chisel started crumpling immediately after sharpening/honing. That is to say, the left corner would crumple while doing a test of sharpness paring pine end grain.
The edge is hollow ground to about 30 degrees, and then honed on Ark stones followed by a strop. It is not burned... really it isn't, I've checked it several times. I even went back and reground the edge a couple of times and turned down the speed all the way down on my 6" grinder just to be sure there would be no burning that I wasn't seeing.
So anyone have any idea why my chisel has a soft spot. Is it possible that I drew some temper while grinding, without seeing any burning? Is it possible that it was improperly treated when it was made and that there is a soft spot that I will eventually grind past?
So do ya'll think?
Since getting them I fixed most of the issues which mainly involved lapping the backs like crazy and grinding past the areas that were back beveled/dubbed. Additionally, The older AI chisels didn't have side walls ground as narrow as they do now, so I also ground down the side bevels to make these more ideal for chopping dovetails.
However, this past week I noticed that the about 1/16-1/8 of the edge/corner of the 3/8 chisel started crumpling immediately after sharpening/honing. That is to say, the left corner would crumple while doing a test of sharpness paring pine end grain.
The edge is hollow ground to about 30 degrees, and then honed on Ark stones followed by a strop. It is not burned... really it isn't, I've checked it several times. I even went back and reground the edge a couple of times and turned down the speed all the way down on my 6" grinder just to be sure there would be no burning that I wasn't seeing.
So anyone have any idea why my chisel has a soft spot. Is it possible that I drew some temper while grinding, without seeing any burning? Is it possible that it was improperly treated when it was made and that there is a soft spot that I will eventually grind past?
So do ya'll think?