
Metal Lathe Made from Scrap Auto Parts - SQL2219
https://flyingkmachines.wordpress.com/
======
dbcurtis
For anyone who likes this sort of thing, the Dave Gingery workshop book series
is a hoot! [http://www.gingerybooks.com](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."

~~~
jfoutz
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.

~~~
mhb_eng
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.

[https://mitpress.mit.edu/books/foundations-mechanical-
accura...](https://mitpress.mit.edu/books/foundations-mechanical-accuracy)

~~~
mhb
Looks good, but it's out of print.

~~~
jdblair
[https://www.ebay.com/itm/FOUNDATIONS-OF-MECHANICAL-
ACCURACY-...](https://www.ebay.com/itm/FOUNDATIONS-OF-MECHANICAL-ACCURACY-BY-
WAYNE-R-MOORE-1970-FIRST-EDITION-NEAR-
FINE/362572699593?hash=item546b0457c9:g:RXMAAOSw2RJcdZZH)

~~~
mhb_eng
There are also a few pdf copies floating around that are acceptable quality.

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paddy_m
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.

Who has a home shop?

~~~
syntaxing
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...

~~~
contingencies
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.

------
sandebert
When society fails and we all live in the dystopic now, I want this guy on my
team.

~~~
gh02t
That and Clickspring. He's got a ton of videos on making ancient tools and
other stuff, well worth watching.

[https://www.youtube.com/watch?v=SOw9WqMOHjA](https://www.youtube.com/watch?v=SOw9WqMOHjA)
\- making files for his recreation of the Antikythera device.

------
newnewpdro
"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.

~~~
serf
>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.

~~~
newnewpdro
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.

[1]
[http://www.engineprofessional.com/TB/TB031516-2.pdf](http://www.engineprofessional.com/TB/TB031516-2.pdf)

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paddy_m
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.

[1]
[https://www.youtube.com/watch?v=kANvdzoVUfw](https://www.youtube.com/watch?v=kANvdzoVUfw)

[2]
[https://www.youtube.com/watch?v=bx80iYfgXkY](https://www.youtube.com/watch?v=bx80iYfgXkY)

[3]
[https://www.youtube.com/watch?v=BjksLl9xur0](https://www.youtube.com/watch?v=BjksLl9xur0)

~~~
jws
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.

------
davidbanham
That's awesome! I wonder what kind of tolerance its able to work to.

------
jmpman
Needs some JB Weld

~~~
mrob
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:

[https://www.youtube.com/watch?v=MtxA20Q-Uss](https://www.youtube.com/watch?v=MtxA20Q-Uss)

The rest of this video series is also well worth watching.

