Here's a photo of a TN rifle. In addition to just seeing the quality of the work, I found it helpful to see this pipe for a few other reasons as well.
At first glance when seeing the thing in real life, it looked "wafer-thin", (to borrow Acer's apt description).
Then when looked at under magnification, it seemed evident that the thing had to have been filed from reasonably thick material. Otherwise there simply would not have been enough material for such deep "grooves" in the fluted section.
And then there is the problem of the damaged edge. By filing the edge to a delicate "wafer-thin" dimension (and thus creating something of an optical illusion) the smith may have made it too fragile. As Dan P points out, an overly thin pipe collapses and jams or cuts into the rod. (Maybe a slightly heavier beaded edge would have been a better choice, since a bead would have given strength to the edge?)
I try to make my iron mounted stuff out of scrap when I can. But sometimes I buy hardware grade "welding steel" sheet. It might be helpful to guys to know that the actual dimensions of hardware grade 16 ga sheet varies quite a bit. I've found it to vary from .043-.058. The 22 ga has been more consistent, usually .025. That doesn’t mean you need to pay big money for exact dimension material. But you do want to pay attention to what you are buying, pick through the pile, and buy material according to how you want to use it.
If you are banging the stuff out of scrap or have to work with material that is heavier than you really wanted, then just pretend that you are a smith of old and make due. Hammer it thinner (use hear protection!), or be prepared to file the final product down to the thin profile you want. The point isn’t really how thick of material you start with. Rather, it’s how thick you leave it! And when studying old pieces, keep in mind that there are optical illusions in the artwork. It is supposed to look thin in the final product, but it doesn’t necessarily have to be made so thin as to be fragile.
