The roughly chiseled bottom of the handle mortise is reminiscent of the philosophy of 18th. C. furniture making: If it doesn't show,spend minimal time on it. Later planes had their mortises made of a series of overlapping holes probably made on machinery,but with early type center augers. After drilling out as much as possible,the mortise was squared up on the ends and cleaned on the sides by hand. Also,the mortise slanted backwards on its rear end,and slanted forwards on the front end. The handle fit these angles. This simple but clever angling made it impossible to jerk the handle out of the mortise while pushing the plane. It had to be pulled out backwards if the glue failed. These later mortises were not very crude looking like your earlier looking plane. That feature would be well worth showing to tool curators. I still recommend Colonial Williamsburg. I was the Master Tool and Instrument Maker there for many years,and know the people there very well. Eric is quite a friendly person,and I know he'd like to examine your plane.
Whoever repaired your plane's handle failed to put that feature on the rear end of the handle extension,using a screw instead to hold the handle down.They did do a careful job of mating a locking joint to the back of the handle. The front does show a MUCH steeper angle than later planes have. Too bad the original rear end of the handle isn't there.
Last edited by george wilson; 11-16-2016 at 9:27 AM.