Originally Posted by
Don McConnell
While I generally try to stay out of threads in which it would seem I have a vested interest in the outcome, I'm finally feeling compelled to comment at least briefly on Kees' research. Frankly, I've been hoping someone else would point this out and I could stay out of it. But that doesn't seem to be happening, so, here goes.
There are a handful of difficulties/issues which are inherent in this kind of research, and I'm not completely sanguine that those have been successfully addressed in this research. And I'm not entirely sure how I would address them. But I'll forego that discussion in order to get to the basic flaw I see in the design of this research. As I read the article, Kees, your basic preparation of the iron was to grind at 25º and hone at 30º, resulting in an included angle of 30º for the iron when used at common pitch and with a cap iron. It then seems that you simulated the higher angles of attack by adding a back bevel of 5º, 10º and 15º, which would leave included angles of 35º, 40º and 45º. If this is the case, it is not analogous to an iron prepared with a 30º included angle and bedded at 50º, 55º and 60º, respectively, as would have been done with the 18th century single iron planes with higher bed angles. In other words, you've introduced a variable (actually two, with the subsequent difference in relief, or clearance, angles), which you have not controlled for at all. I believe this brings into question all of the comparative data you've generated, at least as it relates to your primary thesis.
Don McConnell
Eureka Springs, AR