As Taylor mentioned, Peter Berry seemed to ignore centering entirely, and just put his box to the lower edge. If he had any alignment feature in mind, it’s hard for us to understand it now (or maybe it varied over time). The first image shows a box that is aligned somewhat parallel with the comb, but the bottom one seems to have its axis pointing toward the lock panel beaver tail. Berry is hard to analyze. As several guys have said already, sometimes it’s not a matter of math and layout, but just a matter of feel. That may have been the case with Berry. Note that his box final screws are not symmetrical with the rectangular lid. He seems to have been free-handing it. But he was a master craftsman, and so the result seems to work as a whole.
Golden mean as a general principle helps us understand some old art patterns, such as Rocco style scrolls. And it can be very helpful when we try to understand overall proportions, such as why the stock seems to look best if the butt region is only so-wide in relation to the wrist. But there’s a difference between (1) understanding it as an
analysis tool when we study why a design seems to work, and (2) assuming that it was always an intentional and restraining design element (which would imply that the builder did his layout with dividers in hand).
It seems to be certain that some gunsmiths, furniture makers and artists, especially those of the highest skill in Europe, were indeed using dividers when they did their layout. But many American smiths seemed to have just been using a more “natural” layout scheme. (An “eye for it” as Mark Elliot commented.) Thus their work is sometimes a combination of (a) “natural” proportions that are often golden-mean-like and (b) folk art (where things are a bit out of proportion). My sense of it is that work that follows the golden mean in every proportion often looks more European (or at least particularly
refined), whereas work that follows it more loosely or only in some points (such as in general proportions for a Rocco-style scroll) will usually look more American. (But there are certainly a lot of guys on here who understand that relationship better than I do, so I hope others will add comment to my suggestion.)
If you want to build a rifle that more or less “feels” like a particular old builder's style, without copying the old guy’s work exactly, then I do think it is helpful understand these kinds of layout features. And working with dividers and a straight edge can help you understand those features. For example, if you were to copy an old guy’s box pattern but then do the layout and alignment differently, your work would stand out as being different. Such contrasts are one thing that experts are looking for when they try to decide whether or not this or that unsigned rifle was built by this or that old smith. If the box is identical to an Isaac Haines, for example, but the layout and alignment seems to be different from that used in
signed examples by Haines, then they might argue that Haines didn’t build the gun, or that perhaps it is a restocked antique using Haynes parts, etc.
Hope this helps.
Whet
PS: The base files from which these images were compiled were from the “Kentucky Rifle Photographs, Vol. 1, Issue 1, 2005. by The Kentucky Rifle Foundation.” I have simplified the images significantly, and added my own layout lines, etc. If use of these images on the ALR creates copyright issues, then I trust the moderators will let me know.