My search turned up a 7! page thread on the origins of the coffin shape so I figure this must be the place for plane design theory.
I'm referring to the plan view of the sole. Are they often D shaped to protect a vulnerable corner of the plane, Reduce the chance of marring the work, some dynamic of planing, or just for aesthetics?
And a related question. I've seen a bevel put on Japanese style planes from the outside edge to the mouth opening. wouldn't this promote chips getting under the sole instead of being pushed aside?
If it serves an important function why is it not seen on metal or western wood planes?
Any thoughts welcome.
Thanks.