While free-hand sharpening the iron on my No. 5 1/2 jack plane, something occurred to me. The depth adjust on that particular plane has always been tight. No matter how well-oiled the screw or how deep or shallow the frog set, advancing the iron for a deep cut becomes finger-crushing work.
Then, when I was looking for a link to the ruler trick for my previous post, it dawned on me. The bevel on the iron was entirely hand sharpened to about 35 degrees. Meaning the heel of the bevel stuck out further than the factory grinding. Meaning it was butting up against the throat.
So I slapped the iron into a honing guide at 25° and ground the heel of the bevel back down. Now the plane advances smoothly and I didn’t even have to resharpen the edge, as it was well clear of the grinding.
So I guess now I have a hybrid approach for plane iron sharpening. First grind to 25° by guide, then free-hand hone the cutting edge at 35° or so (30° for bevel up tools).