Rounding the back of a paring chisel or slick ever so slightly would have the effect of making it a little less prone to dig in at the corners. In plane blades, which are mostly used bevel down, it is the bevel side which is cambered slightly.
Don, I assume that by demi-bisaigue you mean something like this mortising ax:
http://www.mehr-als-werkzeug.de/product/708364/D-Mortise-Axe/detail.jsf . The one by Stubai appears to have pretty similar proportions. Does someone here have first-hand experience on using one of these, or a bisaigue for that matter?
Mo, my exact thoughts about the mortises. And the broader the cutting edge gets, the more force you need to use to push it through. Mortises aren't my primary concern, though. Most of the work can be done with a chisel and a mallet. But trimming those tenons to fit snugly takes some effort with tools that are more than undersized. My broadest chisels are unfortunately also the shortest.
