Interested in the ggflex

I was looking at the ghost gunner and came across the ggflex. I’m new to the 3D printing world, but this really intrigues me. I found the complete kit on eBay and wanted to know if there is anything else I need to purchase to start finishing my 80 lowers? I’ve read through some of the posts on this forum and it all seems kinda confusing. I enjoy diy and fairly good with a computer. Is this over my skill level? Would something like this be capable of milling a lower from a block of aluminum with the right programming?

Thanks

Here’s the link to the one I was looking at

The kit offering produces a rough equivalent to the factory GG2 unit.
The FLEX project itself defines all the motion components, framing components, and printed parts to build the working frame and CNC/mechatronic motion system. All of these parts were designed and/or specified to make as close of a dimensional clone of the GG2 as possible (in case users want to use a combination of factory and DIY'ed parts, or certain accessories, aftermarket parts, and jig/fastening systems).

The listing you've linked adds a couple additional items onto the basic FLEX design to allow buyers to produce a fully functional machine and not have to source the remaining parts themselves:

1. The Arduino Uno R3/CNC Shield is a basic and affordable microcontroller platform that does all the CNC motion control, specifically by interfacing with a host PC running DDCut software (available through DD's website). This Uno setup is not a perfect analog for current factory machines' control boards, but is more or less identical to older generation Uno/Gshield combos that powered the first couple generations of GG2s. As a side note, the current generation GRBLDC boards are available from DD's online store as replacement parts periodically, but we were unable to grab them in time for the bulk of our development and got the Uno R3/CNC Shield combo going instead.
2. A Carbide Compact/Shapeoko Router spindle; these are a rebadging of OEM Makita RT0701's that are the current spindle standard for the FLEX. They have a couple of desirable features compared to factory Makita's and are more or less as bulletproof as commercially available RT0701's. They are variable RPM, constant torque, and have higher overall power output at given speeds than DD's BLDC spindles, but less fine speed control and more runout as a downside. We've found they are excellent in a wide variety of materials and wanting to make the parts for the FLEX as commercially accessible as possible, the Makita was an almost unanimous choice among the original development team. I'm finishing development of a BLDC spindle setup comparable to DD's factory units, and the toolhead is also modular enough that the machine can be used for whatever tool a user might want to swap on... just in case you need more performance.

So, putting these all together, you'd have a complete machine with more or less the same performance characteristics and capabilities as a factory GG2. To run any of DD's projects (or other projects shared within their community space) you'd just need the associated jigs, tooling, and material; the Uno's functioning through DDCut means all the G-code and motion control is plug-and-play with any .dd files provided... the sole exception being the spindle RPM, which would have to be manually adjusted on the router...

We currently have a wide variety of skill levels among users and I've been trying to help everywhere I can while we build up more of a userbase and I get more devs and forum moderators/troubleshooters on board. There were six of us super active back in November but at the moment I'm almost entirely soloing the project development and management. I'd say if you have some familiarity with 3DP technology and/or DIY'ing other mechanical or shop equipment the FLEX isn't too complicated to get rolling. Unless you've been very active in DIY CNC and 3DP projects there is definitely a learning curve though...

Producing an AR-type receiver from scratch would be *possible* on a larger version of the machine (the framing and motion parts are modular and can be scaled up to accommodate larger material and parts) but would definitely be a task... in short, it would involve a lot of jigs and specialized, long-length/odd-sized machining tools and custom fixtures. My background is in an aerospace and high-pressure parts/tooling job shop, and while I never produced any actual receivers, we did turn out some similarly complex parts that - even with a couple of extremely capable and expensive 5-axis VMC's on the floor - required up to a dozen different drilling and locating fixtures and some specialized tooling to finish... not to mention the work involved in metrology and getting repeatable results out of the machines.

From a glance over the AR lower and some knowledge in the field, I'd say it's probably upwards of 6 different jigs, at least 10 different tools/bits, two distinctly different types of CNC machines, and some hand-finishing on top like tapping and broaching/grinding corners. Doable, but only recommended as a learning/skill-building project or feat of insanity to be able to say you did it. A bunch of other receivers, frames, and parts are simpler and there are a lot more people in the space nowadays trying to make parts completely from scratch... but for now, building absolutely from scratch is still a significant task that is rarely worth the time/money spent. If you're trying to produce dozens of something fairly specialized though, the math changes a bit.

Although... technically the only functional features are the takedown holes, FCG pocket/slot, magwell, and buffer tube mount... so if you don't mind a really ugly and feature-sparse part, you could probably machine these into a ~1.25"x1.75" piece of bar-stock and get something that's actually 'functional' pretty easily.

Regarding the receiver; doing a quick search for my own education, cncguns(dot)com has a fairly understandable and concise writeup. He counts nine distinct operations and I see four (possibly five) different jigs and seemingly around 8 different endmills/threadmills/drills total.

EDIT: He also makes it look way easier than it is, and doesn't mention cost details. Both of these are not to be overlooked... his skill level in particular is obviously significant from the quality of his work. But it is doable!