TomD
"Knowing the resources that a company can and will apply to optimizing a mechanical device(Supersurfacer) I can believe that a 40 degree bed angle and 30 degree blade bevel must be optimum for dealing with a wide variety of hard and softwoods. On the other hand, if one sufficiently searches exceptions can likely be found. If the exception is some wood or wood figure that is rarely used in building stuff this discovery does not detract from the utility of the conclusion. It would seem that effort and electrons would be better devoted to exploring the utility of the cap iron effect in more relevant timbers. "

I'm not sure about that. Mark needs to jump in, but my understanding is that the cutterhead assembly on an SS is/can be designed to rotate in the plan view, and therefore a wide range of cutting angles can be tuned from the bedding angle to angles theoretically near zero bedding angle at zero width. Not sure what the actual working limits of offset are.

Also, I would ask whether your scientific bent is now willing to conclude that 40 degrees is the perfect angle, now that you have read it is so. Or whether it was arrived at out of convention where that is the standard softwood angle for Japanese planes. And some softer hardwoods.

Further, I would ask Mark, what that means, are SS designed mainly for surfacing softer range woods, and is this whole discussion off track as a result, since there are Japanese planes at much higher angles also.