Hello,
I am just an amateur woodworker, who just awhile ago got into building handplanes. I like krenovian approach (gives me an excuse to use combinations of flashy hardwoods :). I have finished now about a dozen wooden handplanes and conditioned (or actually re-built) some cast- iron english Stanleys and one Anant smoother by machining their soles and sides, mouths, beddings and assembly surfaces with a precision milling machines and other such methods. I think they work now as well as those expensive (and beautiful) Lie-Nielsens and Veritas planes. Well, I'd say the Anant smoother costs now about 400-500 USD :). Nothing further on that, just to say that now I have some preliminary experience about making and conditioning planes to somewhat useful woodworking tools.
Okay, during these exercises, it got me thinking one seemingly fundamental design-based thing, on which I have not yet found discussion or comments anywhere. It may be because english language is not my native language and that's why I have missed something. But it still bothers me, and I still I would like to receive some comments and guiding in this matter, which actually fights against certain fundamental classic design principles I have used to keep as rock- solid approach when talking about woodworking handplanes.
Consider the side profile of for example Stanley #5, just to mention one basic design. It's side profile starts as shallow at toe, rising along the side where blade is and then again decreases to the heel. This side profile says that the body construction is most rigid against mechanical bending in the mid-section where the blade and it's adjustments are.
The plane iron itself, when you push the plane forward and blade takes shavings, will create a force which pulls the sole against the wood surface. Then again, when I think of the generally accepted principle that plane sole should be levelled at least at toe region, at heel region and especially at the area right in front of the blade edge, it means that if there is very rigid mid-section structure, the sole must be no only incredibly flat to work well, it is in some cases also difficult to avoid tear-out in very figured wood if the sole region in front of the blade does not stay pressed against the wood surface to be planed. Quite unforgiving system, I'd say.
So, the bothering question is that why plane profile could not be allowed to be a bit more flexible at that region where plane blade and the surface area are? I do not mean paper-thin soles or clearly "springy" action or such, but just enough to utilize that force created by blade. It would still not mean loss of rigidity beyond practical level.
This bothers me, the question why general design fundamentals consider such an unforgiving structures for cast iron handplanes. I know, it works, I have experienced and even created it by myself. I have also experienced surprises that it does not work although everything should be in order. Then again, I have found that I score with better surfaces with wooden planes more often than with cast iron bodied planes despite they are nominally more accurately adjustable. Could it be that this "flexibility" is readily available in the more elastic behaviour of the wooden sole? I somehow do not think that this difference appears directly because of my contribution. For example, due to my day job, I have access to machinery that makes really very true surfaces (for flat surfaces manufacturing, human craftsmanship has really no deal compared to how those machines do and measure their job) and I have for a curiosity done surface truing for some handplanes with them. The result is kinda clear, with similar settings of planes (iron angle, mouth clearance etc.) wooden plane sole works better more often than cast iron plane. To me, this result is also a kind of evidence to support the existence of my current disturbing thoughts of "flexible" sole. I say that I am not starting a crusade, not even arguing anything but just presenting my experiences.
But because here in this newsgroup there seems to visit both professionals and very advanced amateurs, I decided to ask this here. Please, bear with me :)
Yours,
Samu