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Hobby CAD, CNC machining, and resin casting (2015)

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Re: Hobby CAD, CNC machining, and resin casting (2015)

#81

Post by dole »

blackeyeblitzar wrote: post #35

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.

Current hobby 3d printing of metals usually requires a clay-metal type of filament and sintering, usually by heat or laser to harden the metal, and often needing compensation for shrinking and a lot of other inconveniences.

The resultant pieces are "metal" but not strong enough for most internal firearms parts that need to be metal but not necessarily pressure-bearing like a barrel: most notably bolts and carrier groups, fire control group parts like triggers, hammers, sears, disconnectors.

Re: Hobby CAD, CNC machining, and resin casting (2015)

#82

Post by sottol »

Animats wrote: post #50
sottol wrote: post #43

Earlier quoted context omitted.

Good point - there is a provision for laser-cut steel or alu plates that sit inside pockets inside the enclosure panels as I figured many would be turned off by a full plywood design. The metal parts are symmetric so you can cut 2x of each - that is way cheaper on send-cut-send (afair only 25% extra for 2nd part).

> plywood design. Coolant and plywood do not play well together.

The bottom panel is hdpe currently and "trayed", but you wouldn't run this machine with flood coolant anyway. mql might work but the idea was to cut dry, suck away chips and rely on coated end mills.

I've seen people experiment with diesel heater pumps for mql, might try that some time.

coolant always ends up very messy. even mql lubricated chips can be a relative mess compared to dry cutting.

Re: Hobby CAD, CNC machining, and resin casting (2015)

#83

Post by ajot »

hnisoss wrote: post #8

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…

You may also like lcamtuf's current thingy, a substack

https://lcamtuf.substack.com/

Re: Hobby CAD, CNC machining, and resin casting (2015)

#84

Post by syntaxing »

potato3732842 wrote: post #61
syntaxing wrote: post #7

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 ey…

I'd just like to point out how stereotypical of a modern mechanical engineer it is to want to print everything out of plastic and not appreciate the greater versatility of a CNC router. I can't count the number of times I've converted gasketed joints into O-ringed joints, slotted holes, casting lines and welds I've smoothed out. Yes, there are better machines for performing these tasks in metal but I can just tell th…

I think it really depends. 3D printing allows you to be CAD lazy. Things don’t need to make sense as long as the interface is correct. You can also print another part if you mess up. You need to spend some time to make sure CNC parts are engineering sound. But most “experienced” and respectable engineers know their way around the shop. I have zero issues using a manual/CNC mill, grinders, brakes, or drill press. I did it all the time when the schedule is tight, my electrical engineer counter parts would order some off the shelf parts and I’ll modify it for the projects needs.

Re: Hobby CAD, CNC machining, and resin casting (2015)

#85

Post by syntaxing »

jwr wrote: post #73
syntaxing wrote: post #17

Earlier quoted context omitted.

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 have the Carvera (not Air) and it's a very good machine mechanically, the software leaves a lot to be desired. It isn't even close to being the Bambu Lab of the CNC world, unfortunately, but I'd say only because of the software. If they open-source their controller, things might improve quickly.

Oh bummed to hear that, how’s the ATC? The ATC was always the most fascinating part for me for the original Carvera. The Air does not have this feature but it’s expected given the price difference.

Re: Hobby CAD, CNC machining, and resin casting (2015)

#86

Post by syntaxing »

cjbgkagh wrote: post #24
syntaxing wrote: post #17

Earlier quoted context omitted.

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.

Yeah, the 1.5kW spindle + VFD sounds absolutely amazing. It would be pretty nice to be able to cut some steel but not sure if the structure is stiff enough for it

Re: Hobby CAD, CNC machining, and resin casting (2015)

#87

Post by syntaxing »

alnwlsn wrote: post #71
syntaxing wrote: post #7

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 ey…

Any time I see a guide like this, everyone will go on and on about the types of cutters, toolpaths, speeds & feeds, etc. but will always gloss over work holding. For every action, there is an equal and opposite reaction. Without reaction forces, the best cutter in the world is useless. A sizeable chunk of your tooling will just be clamps and indexing tools needed to align and secure the thing you're CNCing, while als…

I didn’t know soft jaws were a thing until I started working. Even in college, they just teach you to hold the part up with spacer plates and crank the vise. One of the vendors I worked with was explaining why 4-5 pieces cost the same as 1 piece. The time and effort to make multiple jaws for each operation is the time consuming and expensive part.

Re: Hobby CAD, CNC machining, and resin casting (2015)

#88

Post by WillAdams »

hnisoss wrote: post #10
WillAdams wrote: post #4

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://…

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..

If you want something lighter than FreeCAD I'd recommend trying Dune3D --- it's amazingly easy/nice to use.

Re: Hobby CAD, CNC machining, and resin casting (2015)

#89

Post by cjbgkagh »

syntaxing wrote: post #86
cjbgkagh wrote: post #24

Earlier quoted context omitted.

Like many things it’ll depend on your use case. Carvera Air is 200W vs Milo 1.5kW which could make a big difference.

Yeah, the 1.5kW spindle + VFD sounds absolutely amazing. It would be pretty nice to be able to cut some steel but not sure if the structure is stiff enough for it

There seems to be an upgrade path for cutting steel with a slower spindle and extra steel plates for added stiffness. There are other DIY CNCs that are designed for steel and use concrete for stiffness which are probably more appropriate - but they do cost more so it really depends on your needs.

What I think will really change things are the 3-in-1 fiber laser sources that can be used for welding, cutting, and cleaning. Building a CNC gantry that can use the cutter means large pieces can be cut from stock plate, assembled like a 3D puzzle, and very quickly welded together. While much more expensive than a Milo it is be a totally different category for capability. Plus a handheld laser welding, cutting, cleaning are very useful tools in their own right. I think laser welding is soaking up most of the supply at the moment but I also think it's just a matter of time before people figure out how to hook up the cutter to a CNC gantry like many already do with hand held plasma torches.

Re: Hobby CAD, CNC machining, and resin casting (2015)

#90

Post by doe_eyes »

blackeyeblitzar wrote: post #35

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.

You can't easily make a high-quality firearm a hobby mill, chiefly because the barrel needs to be made out of good steel and needs to be rifled. But the quirk in the US is that federally, only the receiver is the regulated part, and many types of receivers can be made out of plastic or aluminum. You can certainly use cheap three-axis CNC with some fixturing to make AR-15 receivers, for example, and many people did. Cody Wilson / Defense Distributed had this whole thing where they were selling CNC mills for cranking out guns.

You can also definitely make junk single-use guns using either technology, just like the 3D-printable "Liberator".

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