For anyone who likes this sort of thing, the Dave Gingery workshop book series is a hoot! http://www.gingerybooks.com In volume 1, you learn how to turn a 5 gallon bucket, some refractory cement, a shop vacuum, and a bag of bbq charcoal into a crucible furnace. In volume 2, you learn how to melt down your neighbor's screen door to build a lathe.
7 volumes total. Typeset on a manual typewriter.
My favorite Dave Gingery quote: "I spent half my life trying to figure out how to do a fifty dollar job for fifty cents. I spent the other half looking for the fifty cents."
Those books are amazing. I wound up building a forge, buying a crucible, and making some tongs out of strap iron.
One afternoon i had my mold ready. Fired up the forge, and melted down some aluminum. Then i realized how wildly unprepared i was for dealing with molten metal. i managed to pour a little bit, but that was a fairly dumb risk.
came up with a new plan for a side loading forge, smaller crucible and better tongs. Then i went and bought a little sherline mill.
The book on casting is amazing, and i have no doubt most people can build real tools. but it's going to take a long time, and it's going to take several tries to get anything worth anything.
I don't regret any of the time i spent on it. And perhaps i should have given it a few more weekends. i feel like i got far enough along to get a sense of the scale of what Gingery did. It's amazing. I think he undersells how much skill he built up over 50(?) years. And i think anyone attempting this will realize how painfully unskilled they are. But there's enough there. you can get there if you're willing to put in the time.
On the book front, I'd also recommend Foundations of Mechanical Accuracy by Wayne R. Moore. It's a great treatise on how you can measure things like one millionth of an inch, and has lots of incredible pictures.
Oh yes, those. I read those once when a "prepper" pointed me at them. It's how to build a machine shop from junk, if you're a master machinist. He assumes there's lots of aluminum around.
How many other aspiring machinists hang out here on HN? I have watched a bunch of youtube videos. Over the winter I worked with a guy who ran a small machine shop 3 CNC mills, 1 CNC lathe, a manual mill, a bridgeport. I found working in a shop so satisfying, even mopping the floors. The local makerspace has acquired a bridgeport and a small lathe (12x36) so I will be joining there soon.
I learned machining while in college, as a physics major. That's somewhat of a tradition in physics. Most physics departments have a shop, some are staffed by pro's. Today, there's a small shop at my workplace that's mainly used for custom work, but I use it occasionally for prototyping or modifying things.
In a previous life, I assembled extremely specialized custom CNC's for precise machining of small, delicate parts. We used off the shelf CNC controllers available at the time, which drove large stepping motors.
It's a blast. Be safe.
I noticed the key left in the chuck, on that blog. Oh, my eyes! Granted, it was probably just for taking the picture, but it still gave me the heebie jeebies. ;-)
I have mini home shop if that counts. I don't have much room so I have a Sherline mill and lathe. I used to own a 3020 but I sold that and now I have a shapeoko 2. But to be honest I use my 3D printer a lot more. Subtractive manufacturing is just too expensive. A set of good end mill can cost as much as my Ender 3...
I run a company doing hardware R&D in China, after only basic shop experience in high school (my grandfather was a successful metal factory operator). It's a privilege being here because you can literally summons any component with a few clicks and a couple of days waiting, and costs for precise external fabrication in a wide range of processes are low. So far it's surprisingly hard to find competent multidisciplinary mechanical designers capable of working across processes. We offer a pleasant design office environment as an alternative to a shop floor, which means real estate is more central and quality of life for design engineers goes up. We find this more effective than a self-run shop and it means any design fabricated is known reproducible via outside parties. It has been such an education getting to grips with the production costs and prototype iteration expenses (time and money) on a range of materials and processes. I wish there were an up to date book on this, if there is I haven't found it. As an example, we don't use our own 3D printers because having someone else print, pack, and deliver guarantees engineers stay focused. When you see the big metal shops here, each aisle of machines is often 20 machines and 100+ meters long. They have enormous presses, sheet working areas, laser cutters, many CNCS (Italian, Japanese, German, Korean, etc.) ... it's awesome. Then there's the plastic factories ... massive injection gear sunk in to subterranean concrete grottoes and staggering galleries of client molding stretching hectares.
Back when the TechShop still existed, I developed the original Safety & Basic Usage class for the manual injection molding machine. Not that I was an expert -- I wanted to learn injection molding. But another member was a total expert and he taught me enough that I could use the simple machine and teach the beginner course on it.
So anyway.... I needed to learn mold making. Which meant I needed to learn some CNC. So I did a few simple things on the Tormach 1100 that the TechShop had. Great fun, but it really takes a lifetime to learn all the tricks, if then. I have a friend who's dad owned a machine shop. The guy who finished the 2-year tech school degree and has been a full-time machinist for 10 years is "the new guy". There are so many tricks to planning and fixturing, it is endless. As a hobbyist, I think you just have to decide what it is you want to do, and learn enough to do that, and to do it safely. I have no delusions of ever crawling out of a pit of relative cluelessness.
So I have one of those cheapie manual mini-mills. It is OK for some simple things, I could never make a mold on it. Someday I want to have my own Tormach -- but I already can't park any cars in my garage :/
"Since cylinder bores are bored exactly parallel to each other and at exact right angles to the cylinder head surface, multimachine accuracy begins at the factory where the engine block was built."
My understanding is that this isn't entirely right. The block deforms under the combination of temperature and head bolt tension when fully assembled and in operation, and this is taken into consideration when machining the block.
When cylinders are re-bored there's supposed to at least be a mock head attached and fully torqued to spec to ensure correct results when assembled.
>When cylinders are re-bored there's supposed to at least be a mock head attached and fully torqued to spec to ensure correct results when assembled.
that's not usually true, and it'd be pretty difficult to achieve without a different jig for every engine.
When I spent time in the engine shop, we used a mag-table/mag-chuck for steel parts, and we used table vices/clamps for the rest of it. We would start with inspection and disassembly, move on to parts-holding, and then finally we'd bore/hone/surface, in that order.
There is a 'mock head' installed in that the piece is being held to the work surface, but other than that it's not typical to add more structure when machining -- it makes things much more difficult to move around.
For (very) high performance engines, some manufacturing processes require the engine to wear an external girdle before finish; but it's not too common elsewhere or in the aftermarket world.
For flow-benching head I've have seen the head bolted down like you're talking about, but for that they're trying to approximate an engine's flow.
Are Cummins B series diesel engines considered "very high performance" [1]?
While use of the torque plate in re-boring is apparently more optional than I thought, the point stands; these things aren't ncessarily square when unassembled and the original manufacturer of warrantied engines is going to take distortion into consideration when machining the new parts.
On an unrelated note; EVs can't take over fast enough, good riddance of all this archaic ICE junk.
From what I can see the largest source of inaccuracy with this machine would be in the bed rails. Angle iron has wild tolerances. Still impressive work, more than I can do.
That's an ingenious design, and I get building it as a hack, but old manual machine tools aren't that expensive. I have seen large (16"+ swing 48"+ travel) lathes sell for under $1000 regularly. A couple of observations about old machine tools.
1. The manual machines are really only used by hobbyists anymore. This is less true for Bridgeport mills (almost every shop has one) and manual lathes. For one off jobs which are always needed in a shop, it's much quicker to perform on a manual machine vs a CNC. Manual lathes tend to have a larger work envelope than common CNC lathes.
2. Price doesn't scale with machine size, often the opposite. Bridgeports are universal and in every shop, larger mills less so. A Bridgeport weighs 2000 lbs and sell for $1500-$5000, when you get into 6000+ lb manual machines, they sometimes sell for $500-$3000. The reason is that they are no longer used in production and they are too big for most hobbyists. Moving larger machines is much more difficult. North of 6000 lbs, it is very difficult to haul the machine without a CDL (CDLs are generally required when the trailer is 10K+). Riggers (the craftsmen who load the machine onto a trailer) and transport can cost more than the machine itself.
3. Tooling (drill bits, lathe tools, mills, fixtures) is frequently much more expensive than the machine itself. Finding a machine with tooling is a really good call.
4. There are great deals on machines in the midwest. I scan the detroit and chicago craigslist in particular.
5. Kearney and Trecker milling machines are super cool. They are noted for being the pinnancle of machine tool engineering - all done mechanically [1].
6. For lathes the top brands are probably Monarch and Axleson, followed by mid tiers like Clausing, Leblonde.
7. For all machines, the machinist is more important than the brand of the tool.
8. Avoid older CNC machines, parts are hard to get and expensive. I would be afraid of any CNC machine made before probably 1995.
9. Rigging equipment is pretty cool and necessary for running any type of shop. People do all kinds of cool machine moves with combinations of pallet jacks (~$100 - lifts 5000 lbs), hoists, anchors, Egyptian rolling bars, digging bars, machine skates, and engine hoists. [2] [3] Hire a rigger though.
Patience, a 9’ pry lever, some iron pipe for rollers, and a stack of 2x6 cut offs will handle moving pretty much any machine around the shop. (A pry lever is a long lever with a pair of small sturdy wheels to act as a fulcrum and a short metal tang to jam under equipment. Mine gives me maybe a 2” lift for a 5’ sweep of the handle, so something like a 30:1 advantage.)
Mostly it is just lift-pivot-lower repeated many times to walk a machine along. For longer distances I’ll get it aimed right and up on rollers. For raising or lowering you need an assistant to put the cribbing in or out, but raising a ton of lathe 2 feet to work on the motor underneath is pretty easy, just always have secure cribbing in place so it can’t fall.
Bolting parts together is better because it means you can disassemble it for transport or maintenance. Perhaps surprisingly, this doesn't harm the performance. Lathes, and machine tools in general, are built for extreme stiffness, not extreme strength. Dan Gelbart has a very interesting demonstration showing how a weak structure can still have good stiffness:
7 volumes total. Typeset on a manual typewriter.
My favorite Dave Gingery quote: "I spent half my life trying to figure out how to do a fifty dollar job for fifty cents. I spent the other half looking for the fifty cents."