A Rite of Passage


My grandfather used to own a little toy steam engine that ran on live steam; my dad loved the thing and so did I. It wasn’t until a few weeks ago that I realized I was looking at an industrial age in a nutshell. Also, a very small kid-sized bomb that you can give a kid and tell them “run outside and play.”

Then, a few days ago, youtube coughed up a video from a channel I loosely follow (“blondihacks”) which is someone teaching herself how to be a machinist. It’s actually pretty cool but I find it frustrating because it just makes my hands twitch, as I want to do that kind of thing but I’m already over-committed by a factor of 5, and my milling machine hasn’t got a digital measuring read-out (DRO) – it looks fascinating but I just don’t think I want to go there. And, when I subvocalize the “… yet” at the end of the sentence, part of me knows that I’m not a young person with a 40 year-long runway to learn machining; I’ve got to stay focused at what I’m bad at and I can no longer take on the whole world.

The steam engine was the thing that launched the industrial age [human civilization was already unsustainable but the industrial revolution really put us on course for heat-death] and the invention of precision. Here I must insert a plug for Simon Winchester’s excellent book The Perfectionists [wc] which is about the evolution of precision processes and how they are at the heart of modern civilization. There is an account in Winchester’s book about how Watt invented steam engines, but it was John Wilkinson who made them work correctly. Watt’s pistons were not machined tight enough to the bore and blew steam everywhere, which was quite dangerous under pressure, and Watt was trying various combinations of cork gaskets and oakum to stop the blow-by, when Wilkinson stopped by and noticed the problem. Wilkinson had invented what today we’d call a “boring bar” – not “boring” as in droll and uninteresting, but “boring” as in “boring a hole” or “the bore of a cannon”; the boring bar is a single-point cutting tool that makes a nice, clean, straight, cylindrical cut through a cannon. Or, as it turns out, a steam piston. Winchester’s account is that Wilkinson sent for a massive piece of steel and bored and turned a piston that fit so perfectly that there was no blow-by. Winchester’s book is chock full of fun stories all of which amount to “increasing precision is the pre-condition of modern technology.”

If you want some fun, you can try to get machinists to fight over which was a more important invention: the thread-driven lathe, or the thread-driven milling machine. You can’t make a milling machine without a lathe, and you can’t make a lathe without a milling machine – which came first? Winchester explains the answer, which is rot-13 spoiler:

[Gur svefg nqinaprzrag guernqf sbe yngurf naq zvyyvat znpuvarf jrer unaq-phg, irel pnershyyl, ol svyvat gur guernqf vagb n fgrry one. Bapr lbh unir n frzv-shapgvbany yngur be zvyy lbh pna cebqhpr vapernfvatyl cerpvfr guernqf naq guhf vapernfvatyl cerpvfr zvyyvat znpuvarf naq yngurf.]

There are certain manual processes that result in amazing precision, such as flattening surfaces by using 3 surfaces and interchanging them as you rub them against eachother. It really does work! (and apparently it’s how Charly makes whetstones for knives!) Once you have a couple of pieces of granite that are flattened in that manner, you now have a surface that is flat enough – called a “surface plate” – that you can accurately assemble a piece of high-precision machinery, like a lathe.

That’s a lovely example of the kind of surface plate one might assemble a lathe on; it’s on Ebay right now for a measly $950. The problem is: you are responsible for shipping it. I have no idea what a granite slab that size weighs, but I’m sure that’s out of the reach of a typical small shop fork-lift and, you’ll notice, there are no lifting points on it. Moving something like that is work for an experienced professional rigger with a flatbed semi and a crane truck. With the advent of CNC machines, the market for surface plates has evaporated and you can pick them up for next to nothing on Ebay (don’t ask me how I know) (the first rule of Surface Plate Club is “don’t get me started about surface plates” and the second rule is “don’t bid against a surface plate fanatic on ebay”)

Once you have a single flat plane and a milling machine, you can produce right angles by putting another flat plane at right angles to the first, which eventually evolved into “try blocks” which are steel blocks machined square on a milling machine, that you can position on the surface plate. From there, it’s just geometry. If thinking about this makes your heartbeat quicken a little bit, as it does mine, you might enjoy This Old Tony’s episode on Sine Bars [youtube] which is what you do when right angles are not enough.

Now you can imagine my wistfulness as I watched Quinn machining a steam engine.

Assembling a working steam engine has to be a right of passage for a machinist, and I suspect that many student machinists beat their heads on surface plates in frustration as their teachers inspected the results of their work. If your steam engine starts to blow-by, or leak, or vibrate, or explode even slightly, it shows you screwed up. You can’t fool physics. And, if you think about it, that little machine contains most of the machining skills necessary to build an industrial revolution, by definition. The only part the machinist didn’t do is sand-cast the iron parts, but they’re still truing them up on the milling machine.

That little engine is a machinist’s zen koan; the machined parts must be correct, the bores must be aligned, the bearings must be to tolerance, and best of all it’s small enough that if you screw up the mistake is glaringly obvious. If you decide to watch the video above, there is one moment when Quinn makes a near-fatal mistake and corrects it brilliantly – I cheered out loud.

Another way of doing amazingly high tolerance metal-work is to give an old Japanese guy a bunch of steel and a hammer and some polishing stones and eventually they can make you a katana. Which is the highest form (opinion alert!) of hand-machining humans do. Since a Japanese sword is not derived from a computational model; i.e.: the blade is not defined by a Bezier curve, it just looks like it – I don’t know how one could assign a precision measurement to the accuracy of its shape. But if you look at the facing sides of a masterpiece katana, I’d bet they’re symmetrical to within a thousandth of an inch. And don’t you dare take a machinist’s caliper anywhere near a priceless katana, or you will be murdered by angry old Japanese people. The ends of a machinist’s calipers are hardened and will easily scratch composite steel.

All of this meandering thought is because I keep wondering if I should try to build myself a die filer. I sure could use one in the shop. But the pre-built ones you find are expensive and heavy and have usually been beaten up pretty badly. You want a die filer where the platen is turned as flat as your lathe can manage, and all the surfaces are milled square.

That little beauty is an MLA-18 filing machine, and you can buy them for less than $200 “some assembly required” [mlatoolbox]

Except that “some assembly required” means you’ve got to turn that platen on a lathe, and mill and drill and tap and clean and turn and mill and powder coat and basically have a hell of a time building it. It is also a koan, and it’s one I don’t think I am ready for. I have my old Bridgeport mill, and a metal lathe with a DRO (no DRO on the Bridgeport, I’d have to … measure things)

But, damn, will you have a look at that thing? I want to hear it purr like a kitten. The bottom mechanism that translates the horizontal rotation in to vertical reciprocation lives in an oil-bath behind that bezel with the screws and the machined edges. That’s got to be right, or it’ll leak and then the bearings seize and the machine is 30lb of scrap metal.

I am tempted to buy the parts and work at them slowly over years, leaving them mostly sitting on a surface plate under a layer of WD-40, glaring endless reproach.

Anyhow, congratulations, Quinn, on your steam engine! It takes a whole industrial revolution to make a thing like that.

The Clearfield/Altoon, Pennsylvania area is where America’s great industrial-age machine shops were located. The big machine shop in Clearfield was torn down a few years after I moved here and an ethanol cracking plant was built on the slab. There are old old-school machinists kicking around out here and I’ve talked to a few of them, before the pandemic. They’re nice folks but they’ve generally been generous about knife-making, “it’s an art form, it’s not machining; you guys are more like wood-workers than machinists.” Ow.

Comments

  1. Tethys says

    I have intense shop envy.

    The lathe is prehistoric technology. I just this week watched a seminar on the source and find spots of Neolithic marble bracelets. The bracelets are cool, but my head boggles at the drill cores.

    How did they manage perfectly circular cores without steel tools? I have electricity and fancy diamond edged tools, and still can’t manage to cut out such perfect cores.

  2. StonedRanger says

    I will be 66 in less than two weeks. I went back to school at age 37, after being a high school dropout. It took three years of full time school but I got my degree in manufacturing tech. You are a very talented person, so dont sell yourself short. It only took me three years because of all the silly classes they make you take to get a degree that have zero to do with manufacturing. Its not out of reach. With that machineries handbook, you have every formula you will ever need to figure stuff out. And I have never been to a machine shop where they didnt have at least one surface plate in their inspection department. Even with cnc equipment it is possible to make things that are not parallel or perpendicular. With your skill set you are halfway to being a machinist already.

  3. says

    I loved the book “The Perfectionists” the bit about Wilkinson helping Watt build the steam engine was not something I had known before reading the book.

    There is a museum in Windsor, Vermont that has some great exhibits on early precision machinery, it’s located in the old Robbins & Lawrence factory where many of the innovations in precision were made.
    https://americanprecision.org/
    Another great museum to see early precision machinery at is the Springfield Armory in Springfield Mass, they have some of the original lathes and mills from the 1800’s used to make early muskets, some of them made by Robbins & Lawrence mentioned above. They also have an amazing firearms collection.
    https://www.nps.gov/spar
    Here’s a beautiful old lathe they have:
    https://www.nps.gov/media/photo/gallery-item.htm?pg=3527459&id=871D7B73-155D-451F-6763F7960ECA5CDA&gid=86B997F9-155D-451F-675C87EBB6C66D6B
    It’s an original Blanchard duplicating lathe for making gun stocks.

  4. Pierce R. Butler says

    Winchester’s book is chock full of fun stories all of which amount to “increasing precision is the pre-condition of modern technology.”

    Also a central point of Robert Pirsig’s Zen and the Art of Motorcycle Maintenance, along with a rich assortment of intangibles.

  5. cafebabe says

    Great post. Oddly enough in the god-forsaken remnants of the British Empire(tm) Winchester’s excellent book is titled “Exactly”, with the same sub-title. This variant naming is a remnant of the carving up of the anglophone publishing world by a restrictive trade agreement that decreed that, for example, works published by a US house could only be read by Australians after a UK house licenced and republished the work.
    And as for Blondihacks – well of course women can do machining, the wonder is only that Quinn can overcome the sexism enough to get people to view her blog. I recommend it!

  6. says

    Tethys@#1:
    The lathe is prehistoric technology. I just this week watched a seminar on the source and find spots of Neolithic marble bracelets. The bracelets are cool, but my head boggles at the drill cores.

    That’s why I was careful to say “thread-driven lathe” and ditto milling machine. They existed before, but it wasn’t possible to do precision machining until the motion was controlled by a screw, which made it predictable – and, fascinatingly (to me) made it possible to machine precise screw-threads.

    Winchester, and I think he is right, dates the beginning of the industrial revolution to the invention of the thread-driven lathe. Prior lathes were as precise as their operator.

    I wonder if the potter’s wheel preceeded the lathe, or the other way around. The lathe is a horizontal potter’s wheel, which is a vertical lathe. Though potter’s wheels aren’t single-point shaping.

    I am endlessly amazed at how clever the ancients were. They weren’t stupid, they were just low-tech!

  7. says

    cafebabe@#7:
    And as for Blondihacks – well of course women can do machining, the wonder is only that Quinn can overcome the sexism enough to get people to view her blog. I recommend it!

    I enjoy and respect Quinn’s blog (and work) and I recommend it, too. I also appreciate that she doesn’t “sex it up” – there are a set of female youtube “makers” that make sure their thumbnails feature (prominent) cleavage. That’s OK but it really doesn’t say anything about their making skills, while it says something about their target audience that embarrasses me at male stupidity.

    There’s another really good youtube builder channel that’s run by an older and very well-spoken black woman who is a great mountain of sense. I don’t follow her (so I can’t put my finger on her channel quickly) because she’s a bit more aimed at basic stuff than I’m interested in. But she’s really good.\

    And there’s craftman steady crafting, whose narration just makes me happy.

  8. says

    Pierce R. Butler@#6:
    Also a central point of Robert Pirsig’s Zen and the Art of Motorcycle Maintenance, along with a rich assortment of intangibles.

    There’s that. I saw it as a set of parables about analytic method, which seemed more about debugging than precision. But that’s how koans are, aren’t they?

  9. says

    Patrick Slattery@#5:
    I assume you have seen this?

    Adam’s a hoot!
    I actually haven’t watched the whole episode, which I now need to do. I’m not sure if he goes into how much of the filer needs machining to assemble.

    There are certain things, like sword guards and blade shoulders, that it would be absolutely perfect for. And, I think StonedRanger@#3 is probably right – it’s within my reach. When I look at a platen like that, I can tell quickly where the platen is machined flat on a lathe, or a mill. This one is lathe-work and I do have a substantial lathe. It might be a great learning experience.

  10. says

    Patrick Slattery@#4:
    There is a museum in Windsor, Vermont that has some great exhibits on early precision machinery, it’s located in the old Robbins & Lawrence factory where many of the innovations in precision were made.

    Well, I’ll be going to Vermont again some day. We spent a summer there when I was 4. I need to check that place out.

    The Springfield museum sounds great, too. As Winchester documents, standardizing the machining of firearms allowed for repairable mass-produced firearms, which was a huge innovation that made a great difference between the Napoleonic wars and the US civil war: guns had gotten a lot more accurate and reliable.

    I could spend an hour or two figuring out that Blanchard lathe but I can’t make sense of it from the picture.

  11. says

    Unfortunately Adam does not show the machining necessary the get to the point he shows off in the video, he did make reference to how much he learned though during the process.
    That Blanchard lathe has been out on the floor the few times I went there (My wife goes to the horse show nearby and I go to the Armory) so you can get up close to it.
    Last time I was there, they had a great exhibit with all the major machine guns of WWI.
    They also had an exhibit of the manufacture of the M1 Garand, and the collection has some beautiful Revolutionary war muskets that I thought were modern replicas but that the park ranger assured me were original period.
    Here’s a good video: https://www.youtube.com/watch?v=yIfyzai6Uzk

  12. lorn says

    The only parts that really need to be high tolerance are the piston and valves. A bit of slop in bearings won’t stop it from running. These are typically made as hobby/ proof-of-mastery projects so machinists tend to show off just how fine and pretty they can make things.

    On the other hand, if you just want a little steam engine quick and dirty works. I knew a man who made a rough little engine that drove a small fan that distributed the heat around his cabin. This was a rusty, blackened little engine that he lubed with cooking grease and placed on his wood stove. It would hiss and vibrate but it worked for many years.

    I had an old machinist show me how to hand grind using undersized plugs until you got close and then you mate and lap the parts to a fine fit using the finest abrasive. Even staying with hand power it doesn’t take that long. Use an electric drill and it is a couple of hours at most. The key is using several grades of grinding compound and slow the amount of material removed as it gets almost there.

    In this process there is not a lot of measurement. The actual size of the piston is largely irrelevant. A difference of a tenth of an inch makes no significant difference. What matters is the fit of the piston to the bore and valve to valve body. Once you make one you can produce another in less than a day.

    Depending on materials it is possible to polish a crude little steam engine up and sell them for a considerable profit. The old guy used to make sale models out of copper plumbing fittings, silver solder the major pieces together, polish them on a wheel and sell them at craft fairs. The copper would wear pretty quickly but they were executive toys so nobody complained.

    He could make them out of pretty much any common metal. The one I built was built out of scrap, mostly a fairly mild steel.

    I’ve never tried it but a simple EDM setup could automate the boring/fitting process.

  13. says

    lorn@#14:
    Depending on materials it is possible to polish a crude little steam engine up and sell them for a considerable profit.

    Yep, I know an old guy out here who gets old hit/miss engines and refurbishes them so they look new. He pays less than $100 for one and then sells them for around $1000. They’re works of art by the time he’s done with them.

    I’ve never tried it but a simple EDM setup could automate the boring/fitting process.

    I think the modern way of doing it would be to sand-cast the parts then CNC them. A decent CNC machine ought to be able to fit the parts closely enough that it’d just be a matter of assembly. Of course, there’s no point in jiggering it up for CNC unless you’re going to make lots. So, use the same model(s) to 3D print PLA and make your sand casting molds with the 3D printed pieces. Nope, haven’t been thinking about that stuff at all.

    Then there’s this guy, who uses new listeroid engines to power his neighborhood during bad weather:
    https://utterpower.com/listeroi.htm

  14. lorn says

    Thanks for the link. Those are some lovely old engines.

    In my youth I used to spend time around a dock where some very old fishing boats ran. Several of them had those old single-cylinder diesels. The quirky, irregular, popping and wheezing was music to my ears. Particularly when there was heavy fog. More modern engines, efficient and powerful but without character or heart, came and went while those one-lung-wonders just kept going.

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