Originally Posted by
rob streeper
Added data for more manufacturers today. Fixed a math error present in the first post above too.
The Lie Nielsen bench chisel data shows a surprisingly high standard deviation because one of the chisels is softer toward the cutting edge, apparently it has been overheated at some point.
N.B. Group Std. Dev. = Standard deviation of all of the measurements taken on the chisels of a particular manufacturer, Avg. Std. Dev. = Average of the standard deviations of each chisel for a given manufacturer.