I don't think Cook wrote quite enough about handles in general, but I do think the line of the grip is usually a good indicator of whether the handle will be ergonomic and sparing for the user. Nothing says you cannot have an ergonomic grip without the result causing that line of the lower grip to be drastically altered as they usually do on "curved" handles. I prefer a curved handle to a straight on almost every time, but the line of grip has to be just so.
After I read Peter's addendum to one of the posts on Axeconnected, I made a pretty revelatory connection.
" A little background:
During the early stages of my ax sharpening search, the local old timers were rather vague with advice. They plainly did not think of head/edge shaping in terms of specific angles; if I showed them one of my axes, they felt the bit between their thumb and first finger and (usually) declared it too thick here or there… Only one of them, Arnold Hanscomb, was explicit: he laid a file between the edge and the centre of the ax's eye and said but one word: "FLAT! " He fixed my gaze and repeated "Flat… then you will have an ax that cuts." ALL our axes back then failed that parameter, most of them miserably. Though I later tried to meet his specs, I too failed, mostly because it took a lot of time along with many good files to properly convert the worn and abused old axes we had collected, which had the cheeks too thick to allow for the file (or other straight edge) to lay 'flat' -- that is to contact at once the eye and (almost) the edge.
Some years later I came across Dudley Cook's Keeping Warm with an Ax (now published as The Ax Book) and grasped a few additional details which the old Arnold did not mention, but understood himself, I believe.
Cook, by the way, was far more explicit with regard to ax sharpening than anyone else whose written advice I've come across to date. The angles he offered for the respective parts of the head geometry are, I believe, very sound. Arnold's suggestion of a 'flat' line between the edge and eye more or less corresponds to Cook's 10 degrees. BUT, that holds true to within 1/16" (for felling ax) to 1/8 " (for swamping/limbing) of the very edge -- where the combined angle is gradually increased to approximately 30 degrees in order to provide the needed crumble resistance. Well, 30 degrees or so means lifting the file (or stone) so that it aims about finger thickness above the face. This applies, more or less to majority of North American axes, the thickness of which at the centre of the eye ranges from 1" to 1-1/8". "
If you take a properly filed axe, and compare it to a typical restoration by giving it that little straight edge test, even without messing around with angles you can immediately store a mental image of what it should look like, and you'll know where to file and how much with a little practice. And Peter is right-- it can take a lot of filing to bring it down to where it needs to be.
