I’m eager to hear how it works out, Micah. Lots of ways to skin the cat.
If we were talking about traditional technique alone, I think the case could be made that the barrel was typically inlet first. There are several reasons to assume that. (Forgive me for repeating info that everyone already knows here, but I think it is helpful for the newer arrivals among us.) Sprengel talked about the barrel channel then rod hole sequence in his 1771 article. (JHAT 1988, p 138, 148). We also find antique examples in which the rod hole went badly, and left inadequate web for the forward lock nail, broke through the forearm, or broke through and into the barrel channel.
We also note that many (most?) antiques have a series of “feeler holes” drilled down from the barrel channel into the rod hole. Why a series? If the rod hole were drilled first, then only one or at most two would be necessary (one at the breach and one at the entry pipe). But a whole series seems to suggest that the smith was trying to keep track of where the hole was going in relation to an already established barrel channel.
As for the series of holes, it is also noteworthy that many/most (all?) 18th c antiques that have antique rods still in place have tapered rods. I suspect that at least some of these old guns must have had tapered rod holes, as well. (I need to note here that I have no data to base that on. It’s just conjecture based on the tapered rods. Let me know if you guys get around to measuring the inside diameters of the rod holes of some antiques.)
It is not easy to drill a tapered hole. But is easy to drill and undersized hole and then enlarge it with a tapered reamer. It is also easy enough to move an undersized hole slightly in one direction or another as you enlarge the hole. Did smiths regularly do that? I have no idea. But feeler holes are required if you want to do it successfully. And I know that the technology for how to do it did exist in the 18th c. It’s existence is documented in the tear-dropped shaped broach/reamer that appears in Wyke’s catalogue (see page 31, item 110A-H, and the tear drop shaped cross section in the cut on page 33.)
I hope it is clear that what I’m talking about here is traditional technology. I’m not talking about how to most efficiently skin the cat using contemporary methods. Those are different topics. I'm also happy to note that there is a big contrast between the neatest methods and the more workman-like methods of old.
Whet
Ref:
Wyke, John (John Wyke of Liverpool). A Catalogue of Tools for Watch and Clock Makers. Originally printed between 1758 and 1770. Currently available as a reprint with annotations added, by Winterthur Museum, 1978.
