Building the most accurate DIY CNC lathe in the world [video]
25 comments
·September 3, 2025WillAdams
jjk166
A lathe can't actually replicate itself completely. Specifically, a lathe can only make ways smaller than its own cross slide's stroke. It would also be impossible to make a typical lathe bed on a lathe, though you theoretically could design an unconventional lathe bed that is possible to make on a lathe, even if grossly impractical.
The real starting point for machine precision is rubbing 3 granite plates together.
WillAdams
Yeah, that's a different book, _Foundations of Mechanical Accuracy_:
https://mitpress.mit.edu/9780262130806/foundations-of-mechan...
IAmBroom
Lathes can certainly make cylinders, and a tube-based lathe bed is not a stretch.
A lathe can't replicate its own assembly, of course. It can't seat the spindle in the constraint bearings, for instance.
A CNC (without the word lathe) can make most of itself, and possible all. Nope: certainly all, if two of its dimensions fit within its work volume.
SAI_Peregrinus
Lathes can make cylinders, but not of unlimited length in one setup so they lose some accuracy making cylinders longer than their carriage travel. And their beds are by necessity longer than their carriage travel, since the carriage rides along the bed and isn't infinitely thin. They also can't make things like motor stator laminations, and you definitely need a motor for a replica of a motorized lathe. So lathes can't replicate themselves exactly.
Milling machines are also just lathes with a different orientation, an extra travel axis, and a motor optimized for higher speeds & lower torques, it's possible (and reasonably common) to use a mill like a lathe or a lathe like a mill in many cases. So "only machine" part is also a stretch.
jjk166
But it can't make cylinders as long as its own guide ways.
bluGill
> and is the only tool in a shop which can replicate itself
The real quote is a lathe can build any tool in a machine shop, - including itself. The books your mention describe how to build a lathe with the lathe you are building. (they assume surface plates that the other reply mentioned, but that too is something you can create)
hashishen
most are sold out any kinks to ebooks sold?
bluGill
You can buy the full series. Or check the likes of amazon. The books were first written in 1980, so they are fairly widespread. You can find plenty of youtube videos of people trying to make them, and once in a while forums dedicated to people making them (and suggested upgrades). They are not the best machine cools you can get/make, but they are serious tools and better than most DIY attempts (though the video here is better than most DIY attempts I've seen)
rfrey
People interested in this might also appreciate this small channel: a no-holds-barred 5 axis machine with expected sub-micron precision. I've learned a lot about what kind of components are available when budget is not an issue (I'll bet this machine will cost 100k by the time it's done). https://www.youtube.com/@kasramehraky9283
IAmBroom
Those are the kind of CNC kept in isolated rooms, and covered in gold foil to reflect heat. No humans allowed during the measurement cycle.
rtkwe
For a more rough and ready, but quite entertaining, version of the DIY CNC (mill however) build there's the sage of Not An Engineer's build of a DIY CNC mill.
https://www.youtube.com/watch?v=uallSKJGoug&list=PL3NwjxPeyb...
mdaniel
I love that channel so much
arethuza
Not CNC, but I am addicted to the Cutting Edge Engineering channel:
brcmthrowaway
I can't believe this kid can afford an incredible amount of expensive tools.. daddys money?
fusslo
I've been following Cylo's Garage for a while. I'm excited to see where he goes. Reminds me of Applied Science meets Tom Lipton, Robin Renzetti, or Dan Gelbart.
kragen
Normally I would assume that a YouTuber claiming to have built a more accurate DIY CNC lathe than Dan Gelbart's was full of shit, especially if he didn't mention Gelbart in the title. But Cylo's Garage is an exception. His objective is diamond-turning optics. So he does need tighter precision than Gelbart's 1μm, and he's been working toward achieving it in an astounding fashion for years—inspired, he tells us in the video, by Gelbart.
This video, though? You know how people say "this meeting could have been an email"? This video could have been a web page. Or an email. It's just a set of slides with a voiceover. Save yourself the time and just read the subtitles:
yt-dlp --write-info-json --write-sub --write-auto-sub --sub-lang en --restrict-filenames https://www.youtube.com/watch?v=vEr2CJruwEM
class3shock
It's so cool to see Cylo get posted here. I remember finding his channel via an air bearing video years ago and being so impressed at what a (then) kid was doing, cool to see him still doing stuff and getting recognized for it. For anyone enjoying this Dan Gelberts video on his lathe, which I think inspired this, is worth watching. Robin Renzetti also does cool precision focused stuff but I don't know if he does Youtube much anymore.
zokier
Worth noting that the lathe project itself is on indefinite hiatus right now as I understand it, so don't hold your breath waiting to see finished results.
Joel_Mckay
Most do not understand how difficult these machines are to handle, but there are some completed specialty CNC builds around.
"High precision air bearing CNC lathe and grinder" (Dan Gelbart)
https://www.youtube.com/watch?v=sFrVdoOhu1Q
Cylo's Garage spent a lot of time exploring these designs. =3
Hasz
Also of interest if you enjoy precision engineering: https://www.youtube.com/watch?v=sFrVdoOhu1Q&pp=ygUdZGFuIGdlb...
pillars
Cyrus(creator of Cylo's Garage) written a paper on the diamond lathe design:
https://drive.google.com/file/d/178KoqYAQUScSW27opubo9K794Pe...
Another awesome video on precision engineering resources in the same channel:
pillars
Results of Diamond lathe testing photage: https://m.youtube.com/watch?v=PuSHpD7hiQ0
SilverElfin
It would be interesting to see someone use basic hand tools to build up the evolutionary steps towards high end machining or manufacturing machines of all kinds. Sort of a playbook to restart civilization.
nighthawk454
How To Make Everything on YouTube is along those lines
For folks who are not familiar w/ machine shops, the lathe is a fundamental tool in a shop, and is the only tool in a shop which can replicate itself --- there is even a book series which uses this conceit, the "Gingery Books":
https://gingerybookstore.com/
where Vol. 1 has one setting up an aluminum casting foundry in one's backyard, and Vol. 2 has one using it to make a lathe which is then used to either improve itself or make a better lathe, then one uses it to make the balance of the tools in a machine shop.