beg to differ
Adam Cherubini
>The rounding of the primary bevel so that it blends with the front of the chisel is done to help make a smoother levering out on deep mortises
While I believe this to be true, I'm unwilling to say the round bevel is the result of this. There's no documentation to lead anyone to this conclusion. I think its worthwhile to not attribute the shape to this operation. There may be other reasons.
However that's how early 19th cent. mortise chisels were made.
Made? Look again at Smith's key (I haven't got it in front of me) and tell me if it shows rounded bevels from the manufacturer. Pretty sure they are flat. If, IF, I'm correct, this shows the shape to be user created/intentional. Or is it????
incidently the Sheffield key (1816) lists 3 different styles of these mortise chisel. "mortise chisels", "Best Joiner's Mortise chisel", "Best cabinet mortise chisels"
Gabriel may be of assistance. Setts of joiner's chisels seemed to include larger sizes (required for [house] "joinery") while Cabinetmaker's sets stopped at 1/2" and included 1/8" (I think). Okay, I need to review all this. I think the differences between joiner's mortisers and cabinetmaker's chisels were only the size and possibly the heft, tho I have nothing to base that on.
I know that in Smith's Key, the price list indicates certain styles were available in certain sizes, other patterns or style were available in different sizes. No one chisel was made in every size. This suggests to me that the different patterns were for different operations, and weren't just different strokes for different folks.
The rounded bezel appears on many, many early tools. There's no question that the rounded edge is stronger than a concave bezel. Its formation may have more to do with period sharpening technique than any usage concern, though its easier to control the depth of a pare operation when the bezel is convex/rounded. Tho I pare a lot (as you all know) I'm also unwilling to suggest paring is the reason for the shape.
Adam