Letter Re: The Tomato Rebuild–Machining Technology is Crucial to Modern Society, by Thomas G.

After reading the recent letter by Thomas G, I felt compelled to offer a response to demystify some of the technologies he talked about. First, I am a tool and die maker for an ammunition manufacturer. If it’s broken, I fix it, if we need it, but can’t buy it, I design and make it.

From reloading dies, case feeders, powder measures, primer feeders, cold header press parts, I have done a lot. So I feel somewhat qualified to shed some light onto how things are done. I’ll start basic, and then work up to complex.

Aside from the technology of making metal, the most basic component is arguably the screw, or the nut and bolt. While these can be made on a lathe, that’s simply not practical in the world of mass production. Since at least the turn of the previous century (1800-1900) bolts have been made using machines called headers and rollers. Headers come in two forms, cold and hot. A cold header is typically used for making bolts, these take wire (and by wire, I mean form, not size) the wire is then cut, and pushed into a die. A forming die will then come down and crush the wire that sticks outside the base die, this forms the bolt head, this can also be done for nails, rivets, screws etc. In the case of bolts and screws they are then dropped into a thread rolling machine. This is a device which has two panels which have flattened threads cut onto them, the bolt rolls between the two panels and is threaded.

Nuts are made by hot-heading. A slug of wire is heated until it’s pliable, and is then smashed into a form. When it’s cooled it’s then threaded using a tap.

Gears are made on machines called hobbers, but can be made on a horizontal mill, or a shaper with an indexing head. The hobber works by holding a gear blank between centers, and then has a cutter that rotates above the gear. Once a gear is made, it can be used as a template for casting more, either die cast, or sand cast, depends on size and material.

A lathe is a fairly basic machine, if anyone has ever seen a wood lathe, a metal lathe works on the same principle. If you can build a wood lathe, you can build a metal lathe in a number of iterations. Given the scrap available from even a post-collapse society cobbling a functional lathe together should be fairly easy. The same applies to a mill.

For those who have interest, I suggest checking out the gingery machines web site, and perhaps even buying the book set. While a long time ago I decided it was easier to buy and rehab an old lathe than to build a new one, the books will give even the novice user a good idea about how machines are made.

It is important to note that most machine tools were conceived back in the 1800s. With a few decent measuring tools, almost anything can be made. The greatest thing about the age we live in currently is our ability to measure. If you have a few decent sets of dial calipers, a few dial indicators, a pyrometer (for heat treating) and a stop watch, you can produce just about anything you need.

At times after reading “Patriots” I laugh at the [refugee] character who was the machinist, (Lon Porter) since he carried his tools around in a bicycle trailer. While one tool box may satisfy the storage space required for some measuring tools, it would take a truck to move all of the various tools (tool bits, drill bits, mills, punches, indicators, angle finders,
etc) that I would consider ideal for a post-apocalyptic machine shop.- AVL