Recently I was asked to sharpen three ancient plane irons. The most challenging one was the round, almost semi-circular, blade. I guess it was for an ancient moulding plane.
I mounted the round blade into the scissors jig and quite successfully replicated the existing cutting edge. Near the apex it was quite easy, but both shoulders required small reshaping.
The small change in the edge angle from the apex to both sides of the blade probably could be explained by the wedge shape of the blade clamp. My apex edge angle was some 35°.
The reshaping was done on the SG stone graded coarse, sharpening on SG graded fine. Keeping the iron in the jig I moved to the honing wheel set to the same edge angle as the grinding wheel.
Jan
Jan,
You are well chosen for this task. In addition to the usual technical skill you have the two related key elements for success. Your technical skill is well supported by passion, a belief in the importance of doing your best work to honor the tool and its maker and/or past users. And, you have the patience to stay true to your passion.
Unfortunately, these qualities do not seem to be universal.
Stay true.
Ken