3D printing with PLA has improved in the intervening decade. You can usually get a good print on good modern printers. The first generation of those things had poor extruders, and filament formulation has reportedly improved. There's complicated heat transfer going on in those things. You're welding a hot thing to a cold thing, which is inherently troublesome.
I'm told that works better now.
Machining resin molds is straightforward, because you start with a block of something and machine only its top. So there's no work-holding problem. Trying to figure out how to clamp something that needs to be machined on several sides is usually hard.
Not sure what's going on in tiny mills today. I've used Tormachs, the whole range of Shopbots, and some strange one-off machines that TechShop somehow obtained. (Never did use the beautiful little Pocket 5-axis machine. TheShop had one just before they went bankrupt.)
awesome dump, thanks for sharing. solvespace is cool but until they iron out the chamfer/fillet situation and parametric input I ll have to continue using freecad..
Former MechE for a decade and I owned personal CNC routers and on my 6th 3D printer. The biggest issue with CNC is the cost for consumables and accessories. Need a special bit? $$$ Need stock to cut? $$$ Want a nice ER11 or R2 collet set? $$$. A nice vise? $$$ Cut something wrong with a carbide bit? Shrapnel explosion. 3D printing has a bunch of limitations but is a way better machine for hobbyist. But I have been eyeing the Millennium Machines Milo. A very fair price point for a traditional style CNC. You can also decorate it however you want with your 3D printer.
It is definitely more expensive than 3d printing in terms of consumables but china/aliexpress has really good hobby-quality equipment now - if you don't mind the country of origin. Many of their coated end-mills are decent and < $5 depending on diameter.
Maybe not stuff you would want to run professionally but it works quite well in a hobbyist setting and a mistake won't cost you $50.
I also looked into the Millenium Milo, only downside for me and kinda why I decided to design my own Voron V0-ish sized mini CNC machine was the really large footprint for about 3x the work volume (work _area_ is ~2x afair). An enclosed Milo would take up about the same volume as two 350mm Voron's side-by-side. So footprint of a small desk.
Imo besides the price, the other big factor is just how much less forgiving CNC machining is than 3d printing - so many mistakes you can make, zeroing the WCS, wrong WCS, mounting the work different than you had it in CAM, ... bam, at least the work is ruined. That's kind of another longer-term goal with my CNC machine, reducing some of these errors if possible with a web-based UI and maybe some computer vision. But that's far off, I'm currently playing with using a camera for work-probing/WCS-zeroing and it's sloooow progress :')
Have you seen the Carvera Air? Not gonna lie, I'm equally tempted but that price point is tough to swallow. Its about $7-800 more than the Milo but has a bunch of things built in that you would probably would enjoy like touch probe leveling and camera zeroing. Its the "Bambulab" of the CNC world.
I was in charge of one of these when I was way younger and they are awesome. Downside is that I don't want to house Argon and they're such a pain to maintain. Getting parts ordered is definitely magnitudes more efficient and significantly cheaper nowadays. You can get really nicely machined and anodized parts from China for the same cost as custom part shipping cost here in the states, it's crazy.
The noise from having a router and vacuum dust-collection running all the time can become a problem in residential areas. Most would like a full-sized machine that could directly handle standard sheets of material, but the space is not the only limiting factor (i.e. the insurance provider could pull something nasty with your mortgage creditors etc.)
Peoples situations will differ, and definitely check out reverse-spiral flute carbide-cutters if you handle a lot of sheet-work on a 2.5D setup =3
Shameless plug if anyone is interested - I'm working on a $600-ish open-source, reasonably capable, but small and somewhat "tidy" hobby CNC machine with BOM cost around $600 that requires some DIYing.
It's meant to be an alternative to the Desktop CNCs like Nomad, Carvera, Bantam, ... moreso than a PCNC or other proper entry-level CNC.
The ultimate goal is to make it hobbyist-friendly, capable of easily cutting alumin(i)um and not taking up a lot space, not being messy or loud enough to require a dedicated workshop. Unfortunately, cutting metal is inherently loud so you probably would not be able to run it in an apartment as I'd hoped.
I've made a couple decisions around being friendly for people coming from the 3DP space around probing, using roborock CPAP as chipvac, running it mostly dry, fully enclosed. I'm also starting to work on computer-vision-based probing and the idea is to later enable a host of more user-friendly and safety-focused features and maybe integration with Kiri:Moto's CNC mode for "guided" CAM and so on - basically a beginner-friendly CNC that guides newbies using an integrated web-interface.
GH is a little outdated but I've been using the little machine to cut alu for a while (mostly parts for itself) and it's working quite well. There's more videos and such on the Discord linked in the GH readme - feel free to ask questions on the Discord, I try to respond as quickly as I can. The full model with all its components is completely open in Onshape (I know it's not ideal but how I learned CAD - link also on GH).
Fully enclosed with a chip vac is good. Chips all over the place is no fun. Especially with coolant.
Don't expect people to precision-cut wood for the frame. The Liteplacer people tried that for their pick and place machine, and most people never got a working machine.
If it needs plates with holes in them, make them in bulk and sell them. Waterjets are good for that. The holes will be where they are supposed to be.
(The Liteplacer was a really good idea - a pick and place machine for assembling prototype PC boards. Camera controlled, with the input parts in partitioned trays rather than reels, it was slow but did the job precisely. The PixiePlacer seems to be the next generation of this. But, as with the Liteplacer, you can't just order the metal parts. You have to make them or have them made. There are commercial machines, of course, but they're for production, feed parts from reels, and are more expensive.)
This would be a lot more interesting if it could cut steel and titanium. I guess that is more difficult.
Added: a dumb question, if the main cutting device is a router with a spinning bit, how do you cut angles? One thing I'd like to make is a 4mm hexagonal hole in a piece of steel, to turn little hex drive screwdriver bits and the like. Is it even possible to make that with a mill, or do you need a different machine?
That's usually done with something called a rotary broach.[1] This is a clever trick. You first make a round hole. The rotary broach is a hex-shaped cutting tool. Both workpiece and tool are clamped in a lathe. But the center of the tool is slightly offset from the rotational center of the workpiece. Both spin, but the eccentricity makes it cut a hexagonal hole. Here's the process.[1]
A milling machine can cut a hexagonal hole, but the inside radius at each corner cannot be smaller than the radius of the cutter. A 4mm hex hole would require a tiny cutter to do a good job. Here's that process for a larger hole.[2]
If the hole goes all the way through, just get a hexagonal punch. Might need to drill a round hole first.
Or just buy a 4mm socket with a T-handle. Cost US$4.99.[3]
Steel is sooooooooooooo much harder than al, it’s not even in the same ballpark. Aluminum is about as hard to cut as wood. For non round holes, you are looking at approximations or broaching. Look up manual hex broaching
What's the advantage of this over a 3018 or 3030 machine? With some basic upgrades (you mentioned needing to diy anyway) you can easily cut aluminum on those for $500 or less.
I tried [1] - replaced the sides with 2040s, blind-jointed every extrusion, replaced X with MGN12H + 4 carriages, replaced the whole Z with 4080U and even bolted it into an MDF box to stiffen it up. The 3018 could cut alu, but not well. Maybe it was the 4080U but it just didn't work for me, it could cut alu but had lot of chatter.
For $600-800 it is fully enclosed, includes a decent spindle, wifi-enabled +offline RRF-based controller with folding/rotating LCD screen, 2 power supplies (24V + 48V for the spindle), a chip vacuum and probably some more I forget.
This machine was designed [3] specifically to cut alu rather well for < $1000, can run adaptive clearing toolpaths at 0.5mm optimal load and 3mm doc at 1800 mm/min with a 6mm end mill and produce decent chips. It can probably do more, my standard settings are 1200mm/min, 0.5 woc, 3mm doc. Mind you, this is all still hobby-level though you could still push the feeds and speeds a bunch I reckon.
that looks like a nice project, reminds me of the ghost gunner 3 machine.
I like the safety note too. might hop into discord sometime next week. thanks for sharing!
With some concerted effort and money spent over several years I was able to more or less reproduce most of this document (but not nearly to the level of detail or variation on process). Eventually I was able to finely CNC engrave a wax block with extremely fine (0.1mm) features, make a mold, and then stamp out as many copies as I wanted. This guide was really helpful in understanding some of the core ideas.
I'm not too excited by the idea of making little plastic precision gearboxes for robots, so when PLA printing isn't good enough, I mostly want to machine metal. Not car parts or firearms but flashlight bodies, knife blades, small tools, that sort of thing. Nothing wrong with robotics but there are other interesting areas too. I think the article skips over that a little too easily. That said, it's a good article.
oh my! I found this exact page in ~2017. I m something of a tab hoarder and I had around 2k open tabs back then. I loved the page and content and wanted to get back to it, but you know how it goes. Somewhere in early 2018 my browser crashed and I lost the tab. I distinctively remembered losing that page and I tried to find it, over and over again. I actually had one of the pictures saved (blue-red-white wheel), so I opened it in new tab as placeholder until I find the page. 6 years later here we are!!! tnx hughgrunt xd
Has anyone here tried using CNC machines for gunsmithing as a hobbyist? Is that even feasible? What about 3-D printing metals instead of plastic? To be clear, I know little about either firearms or metal working, but it seems like it would be an interesting engineering challenge for a hobbyist.
For one thing, IME with cheap hobbyist 3d printers (e.g., Ender printing PLA), the article is dead on about accuracy... people say 3d printers are good for 0.1mm but I don't know how long they spend tuning the machine. I mean, they are... kind of... just not reliably. CNC accuracy of 0.025mm is much easier to achieve (IME).
If you mean to tell me that I should just have a resin printer to start with, well I agree but I think we should be specific about what kind of 3D printing we are discussing.
Remember, the guide was written over a decade ago. Certainly 3d printing has gotten better, cheaper, and a lot more reliable. Resin is really strong, though.
That was written before resin printers were affordably available or input shaping and so forth had made such a leap in print quality for fused filament printers --- that said, I get much better surface finishes on my CNC machines than my 3D printers, and casting will reproduce even the tiniest imperfection.
It depends on the accuracy you are trying to achieve, and with what technology.
If you mean FDM, it's absolutely true.
If you mean SLA/MSLA these days, i think you could get there.
On the first - i have an entirely ballscrew + linear rails driven FDM printer with closed loop servos and proper absolute encoders - I got bored and do lots of CNC retrofits/etc, so had lots of parts around. Think of it as insane version of the Pantheon HS30, if you didn't care at all about costs or practicality.
It can position, at speed (IE 300mm/s+), and repeat, the nozzle placement to within 0.0005 inches on all axes, easy.
But even with input shaping/etc, you will not get a better surface finish than CNC, and definitely not one good enough for casting.
Filaments are just too finicky, even with really really good hotends, sensors everywhere to monitor response and optimize, etc.
Now, i did this for giggles, and yeah, i never get misplaced layers, my parts are consistent, etc.
But 0.4mm is still a pretty big feature size, and that's the minimum if i don't want prints to take until the heat death of the sun.
So I could still machine the same thing on my metal mill and achieve castable surface finish, etc, in much less time and effort.
This sounds fun, have you written anything up about this project? I’ve been considering switching to ball screws and closed loop servos on my next project. I’d be especially curious for component recommendations for hobbyists, as it seems like ball screws and servos are often super expensive or suspiciously cheap.
Previous discussions:
https://news.ycombinator.com/item?id=41467268
https://news.ycombinator.com/item?id=27645605
This was a resource which was mentioned on the Shapeoko wiki --- while it's off-line, it's still on the Wayback Machine: https://web.archive.org/web/20211127090321/https://wiki.shap...
Since then, some of those pages have been made available on Reddit:
https://old.reddit.com/r/hobbycnc/wiki/index
https://old.reddit.com/r/shapeoko/wiki (ob. discl., I work for Carbide 3D)
And there have been a number of other developments
- FreeCAD has hugely improved since that was written.
- Solvespace as greatly improved, adding some basic CAM functionality
- Blender has had the Solvespace sketcher ported to it as https://www.cadsketcher.com/ and BlenderCAM has gotten quite a bit more workable
- Dune3D was created and is remarkably capable: https://dune3d.org/
Also a fair number of forums discussing CNC were gathered at: https://forum.makerforums.info/
Right. This article is (2015).
3D printing with PLA has improved in the intervening decade. You can usually get a good print on good modern printers. The first generation of those things had poor extruders, and filament formulation has reportedly improved. There's complicated heat transfer going on in those things. You're welding a hot thing to a cold thing, which is inherently troublesome. I'm told that works better now.
Machining resin molds is straightforward, because you start with a block of something and machine only its top. So there's no work-holding problem. Trying to figure out how to clamp something that needs to be machined on several sides is usually hard.
Not sure what's going on in tiny mills today. I've used Tormachs, the whole range of Shopbots, and some strange one-off machines that TechShop somehow obtained. (Never did use the beautiful little Pocket 5-axis machine. TheShop had one just before they went bankrupt.)
"GatorCAM for CNC"
Instructions to download: https://youtu.be/hqyPzCKGUQc?si=VJ0KRhQOl_-d7Bmm
Download here: https://sites.google.com/view/gatorcam/home
Very user friendly. Tab support, v-bit, ATC, sorts toolpaths for faster carving.
These also had discussions:
https://news.ycombinator.com/item?id=4679939
https://news.ycombinator.com/item?id=34339459
awesome dump, thanks for sharing. solvespace is cool but until they iron out the chamfer/fillet situation and parametric input I ll have to continue using freecad..
Former MechE for a decade and I owned personal CNC routers and on my 6th 3D printer. The biggest issue with CNC is the cost for consumables and accessories. Need a special bit? $$$ Need stock to cut? $$$ Want a nice ER11 or R2 collet set? $$$. A nice vise? $$$ Cut something wrong with a carbide bit? Shrapnel explosion. 3D printing has a bunch of limitations but is a way better machine for hobbyist. But I have been eyeing the Millennium Machines Milo. A very fair price point for a traditional style CNC. You can also decorate it however you want with your 3D printer.
It is definitely more expensive than 3d printing in terms of consumables but china/aliexpress has really good hobby-quality equipment now - if you don't mind the country of origin. Many of their coated end-mills are decent and < $5 depending on diameter.
Maybe not stuff you would want to run professionally but it works quite well in a hobbyist setting and a mistake won't cost you $50.
I also looked into the Millenium Milo, only downside for me and kinda why I decided to design my own Voron V0-ish sized mini CNC machine was the really large footprint for about 3x the work volume (work _area_ is ~2x afair). An enclosed Milo would take up about the same volume as two 350mm Voron's side-by-side. So footprint of a small desk.
Imo besides the price, the other big factor is just how much less forgiving CNC machining is than 3d printing - so many mistakes you can make, zeroing the WCS, wrong WCS, mounting the work different than you had it in CAM, ... bam, at least the work is ruined. That's kind of another longer-term goal with my CNC machine, reducing some of these errors if possible with a web-based UI and maybe some computer vision. But that's far off, I'm currently playing with using a camera for work-probing/WCS-zeroing and it's sloooow progress :')
Have you seen the Carvera Air? Not gonna lie, I'm equally tempted but that price point is tough to swallow. Its about $7-800 more than the Milo but has a bunch of things built in that you would probably would enjoy like touch probe leveling and camera zeroing. Its the "Bambulab" of the CNC world.
Like many things it’ll depend on your use case. Carvera Air is 200W vs Milo 1.5kW which could make a big difference.
A reasonable quality plasma-cutter CNC table offers the speed and low operational cost most fabricators can manage well.
Having a CNC Router table in a non-industrial zoned area will not work for most people. Services like sendcutsend.com makes life so much easier... =3
I was in charge of one of these when I was way younger and they are awesome. Downside is that I don't want to house Argon and they're such a pain to maintain. Getting parts ordered is definitely magnitudes more efficient and significantly cheaper nowadays. You can get really nicely machined and anodized parts from China for the same cost as custom part shipping cost here in the states, it's crazy.
Budget 3D metal printers will eventually enter the hobby market, but I only get to work on my hobby on Saturdays. =3
I use mine in my (finished) basement, or if cutting tropical hardwoods out on my back deck (I have a machine on a wheeled cart).
The noise from having a router and vacuum dust-collection running all the time can become a problem in residential areas. Most would like a full-sized machine that could directly handle standard sheets of material, but the space is not the only limiting factor (i.e. the insurance provider could pull something nasty with your mortgage creditors etc.)
Peoples situations will differ, and definitely check out reverse-spiral flute carbide-cutters if you handle a lot of sheet-work on a 2.5D setup =3
Shameless plug if anyone is interested - I'm working on a $600-ish open-source, reasonably capable, but small and somewhat "tidy" hobby CNC machine with BOM cost around $600 that requires some DIYing.
It's meant to be an alternative to the Desktop CNCs like Nomad, Carvera, Bantam, ... moreso than a PCNC or other proper entry-level CNC.
The ultimate goal is to make it hobbyist-friendly, capable of easily cutting alumin(i)um and not taking up a lot space, not being messy or loud enough to require a dedicated workshop. Unfortunately, cutting metal is inherently loud so you probably would not be able to run it in an apartment as I'd hoped.
I've made a couple decisions around being friendly for people coming from the 3DP space around probing, using roborock CPAP as chipvac, running it mostly dry, fully enclosed. I'm also starting to work on computer-vision-based probing and the idea is to later enable a host of more user-friendly and safety-focused features and maybe integration with Kiri:Moto's CNC mode for "guided" CAM and so on - basically a beginner-friendly CNC that guides newbies using an integrated web-interface.
More info on Github: https://github.com/thingsapart/mini_nc
GH is a little outdated but I've been using the little machine to cut alu for a while (mostly parts for itself) and it's working quite well. There's more videos and such on the Discord linked in the GH readme - feel free to ask questions on the Discord, I try to respond as quickly as I can. The full model with all its components is completely open in Onshape (I know it's not ideal but how I learned CAD - link also on GH).
Fully enclosed with a chip vac is good. Chips all over the place is no fun. Especially with coolant.
Don't expect people to precision-cut wood for the frame. The Liteplacer people tried that for their pick and place machine, and most people never got a working machine. If it needs plates with holes in them, make them in bulk and sell them. Waterjets are good for that. The holes will be where they are supposed to be.
(The Liteplacer was a really good idea - a pick and place machine for assembling prototype PC boards. Camera controlled, with the input parts in partitioned trays rather than reels, it was slow but did the job precisely. The PixiePlacer seems to be the next generation of this. But, as with the Liteplacer, you can't just order the metal parts. You have to make them or have them made. There are commercial machines, of course, but they're for production, feed parts from reels, and are more expensive.)
What about the lumen from opulo?
I uploaded a quick video of it cutting some alu recently if anyone's interested:
https://youtube.com/shorts/XUsj06iMbb0
At first I was skeptical, but that's an impressive demo for such a small machine.
The documentation on your github is a tad lacking however. :)
But good luck on your machine, I like your CPAP fan idea.
This would be a lot more interesting if it could cut steel and titanium. I guess that is more difficult.
Added: a dumb question, if the main cutting device is a router with a spinning bit, how do you cut angles? One thing I'd like to make is a 4mm hexagonal hole in a piece of steel, to turn little hex drive screwdriver bits and the like. Is it even possible to make that with a mill, or do you need a different machine?
That's usually done with something called a rotary broach.[1] This is a clever trick. You first make a round hole. The rotary broach is a hex-shaped cutting tool. Both workpiece and tool are clamped in a lathe. But the center of the tool is slightly offset from the rotational center of the workpiece. Both spin, but the eccentricity makes it cut a hexagonal hole. Here's the process.[1]
A milling machine can cut a hexagonal hole, but the inside radius at each corner cannot be smaller than the radius of the cutter. A 4mm hex hole would require a tiny cutter to do a good job. Here's that process for a larger hole.[2]
If the hole goes all the way through, just get a hexagonal punch. Might need to drill a round hole first.
Or just buy a 4mm socket with a T-handle. Cost US$4.99.[3]
[1] https://www.youtube.com/watch?v=_AYEFjbGaL4
[2] https://www.youtube.com/watch?v=zOqSIRuBgCY
[3] https://www.amainhobbies.com/rc4wd-metric-hex-twrench-tool-4...
Steel is sooooooooooooo much harder than al, it’s not even in the same ballpark. Aluminum is about as hard to cut as wood. For non round holes, you are looking at approximations or broaching. Look up manual hex broaching
What's the advantage of this over a 3018 or 3030 machine? With some basic upgrades (you mentioned needing to diy anyway) you can easily cut aluminum on those for $500 or less.
I tried [1] - replaced the sides with 2040s, blind-jointed every extrusion, replaced X with MGN12H + 4 carriages, replaced the whole Z with 4080U and even bolted it into an MDF box to stiffen it up. The 3018 could cut alu, but not well. Maybe it was the 4080U but it just didn't work for me, it could cut alu but had lot of chatter.
For $600-800 it is fully enclosed, includes a decent spindle, wifi-enabled +offline RRF-based controller with folding/rotating LCD screen, 2 power supplies (24V + 48V for the spindle), a chip vacuum and probably some more I forget.
This machine was designed [3] specifically to cut alu rather well for < $1000, can run adaptive clearing toolpaths at 0.5mm optimal load and 3mm doc at 1800 mm/min with a 6mm end mill and produce decent chips. It can probably do more, my standard settings are 1200mm/min, 0.5 woc, 3mm doc. Mind you, this is all still hobby-level though you could still push the feeds and speeds a bunch I reckon.
[1] https://youtube.com/shorts/C0ngUJrWrB4
[2] https://youtube.com/shorts/XUsj06iMbb0
Not made in china though since many parts come from china anyway...
that looks like a nice project, reminds me of the ghost gunner 3 machine. I like the safety note too. might hop into discord sometime next week. thanks for sharing!
With some concerted effort and money spent over several years I was able to more or less reproduce most of this document (but not nearly to the level of detail or variation on process). Eventually I was able to finely CNC engrave a wax block with extremely fine (0.1mm) features, make a mold, and then stamp out as many copies as I wanted. This guide was really helpful in understanding some of the core ideas.
I'm not too excited by the idea of making little plastic precision gearboxes for robots, so when PLA printing isn't good enough, I mostly want to machine metal. Not car parts or firearms but flashlight bodies, knife blades, small tools, that sort of thing. Nothing wrong with robotics but there are other interesting areas too. I think the article skips over that a little too easily. That said, it's a good article.
I read this when I was 25 and now I have a fanuc Robodrill in my garage. CNC is quite the bug
oh my! I found this exact page in ~2017. I m something of a tab hoarder and I had around 2k open tabs back then. I loved the page and content and wanted to get back to it, but you know how it goes. Somewhere in early 2018 my browser crashed and I lost the tab. I distinctively remembered losing that page and I tried to find it, over and over again. I actually had one of the pictures saved (blue-red-white wheel), so I opened it in new tab as placeholder until I find the page. 6 years later here we are!!! tnx hughgrunt xd
I remember reading this around a decade ago. Still holds up though
Has anyone here tried using CNC machines for gunsmithing as a hobbyist? Is that even feasible? What about 3-D printing metals instead of plastic? To be clear, I know little about either firearms or metal working, but it seems like it would be an interesting engineering challenge for a hobbyist.
It’s hard for me to believe that using a CNC to mill a model for resin casting works better than 3D printing it and casting it.
I’d expect that with 3D printing you can even print the spruce and risers.
For one thing, IME with cheap hobbyist 3d printers (e.g., Ender printing PLA), the article is dead on about accuracy... people say 3d printers are good for 0.1mm but I don't know how long they spend tuning the machine. I mean, they are... kind of... just not reliably. CNC accuracy of 0.025mm is much easier to achieve (IME).
If you mean to tell me that I should just have a resin printer to start with, well I agree but I think we should be specific about what kind of 3D printing we are discussing.
Remember, the guide was written over a decade ago. Certainly 3d printing has gotten better, cheaper, and a lot more reliable. Resin is really strong, though.
That was written before resin printers were affordably available or input shaping and so forth had made such a leap in print quality for fused filament printers --- that said, I get much better surface finishes on my CNC machines than my 3D printers, and casting will reproduce even the tiniest imperfection.
It depends on the accuracy you are trying to achieve, and with what technology. If you mean FDM, it's absolutely true. If you mean SLA/MSLA these days, i think you could get there.
On the first - i have an entirely ballscrew + linear rails driven FDM printer with closed loop servos and proper absolute encoders - I got bored and do lots of CNC retrofits/etc, so had lots of parts around. Think of it as insane version of the Pantheon HS30, if you didn't care at all about costs or practicality.
It can position, at speed (IE 300mm/s+), and repeat, the nozzle placement to within 0.0005 inches on all axes, easy.
But even with input shaping/etc, you will not get a better surface finish than CNC, and definitely not one good enough for casting.
Filaments are just too finicky, even with really really good hotends, sensors everywhere to monitor response and optimize, etc.
Now, i did this for giggles, and yeah, i never get misplaced layers, my parts are consistent, etc.
But 0.4mm is still a pretty big feature size, and that's the minimum if i don't want prints to take until the heat death of the sun.
So I could still machine the same thing on my metal mill and achieve castable surface finish, etc, in much less time and effort.
This sounds fun, have you written anything up about this project? I’ve been considering switching to ball screws and closed loop servos on my next project. I’d be especially curious for component recommendations for hobbyists, as it seems like ball screws and servos are often super expensive or suspiciously cheap.