Sunday, March 04, 2012

CNC'n'thee

Og's second post on the manufacturing behind the AR.

Interestingly, it's the sophisticated manufacturing processes that allow the rifle itself to be so simple. And it is mechanically simple, don't let anybody tell you otherwise. I've assembled a lower while sitting on the futon watching television with no tools other than a punch and using a TV tray and my lap as work surfaces, and the carbine built on that lower then went through a three-day Awerbuck class, an Appleseed, and several range sessions without a malfunction.

12 comments:

Homer said...

Which is why the AR platform is such a great tool. The engineering and manufacturing ends absorbed the expensive head work so everything downstream didn't have to. Users can concentrate on using.

Angus McThag said...

But but but...

Arfcom and M4carbine both say that any home built AR will fail catastrophically, killing you, maiming your family, causing your car to explode and pets to develop loss of appetite and ringworm!

Only Colt (PBUT) can make a carbine capable of surviving even a single shot under "course conditions".

Or is Tam secretly a Tier One manufacturer sitting there with her TV tray?

I've said too much!

Tam said...

McThag,

"Or is Tam secretly a Tier One manufacturer sitting there with her TV tray?"

Or maybe Tam used Tier One parts on her Tier Seven TV tray. ;)

DirtCrashr said...

It's the Uppers that take a few more resources and patience - and a vise mounted to the TV tray! :-)

Roberta X said...

Nope. I did my AR on a TV tray (or hand-held), too -- all of it.

They're just not that complicated nor are they tricky, except for the teeny little spring-loaded pins that leap out and are Lost Forever. Luckily, I had spares.

Roberta X said...

WRONG! Tam reminds me that I cheated and bought a fully-assembled upper. ::blush:: Gee, I thought that part was way easy....

Tam said...

DirtCrashr,

"It's the Uppers that take a few more resources and patience - and a vise mounted to the TV tray! :-)"

Nah, you just buy those pre-assembled. ;)

Noah D said...

I still love AKs. I know, bad design, flexes all over the place, cracks at the trunnions, short sight radius, yeah, yeah...

It's not a rational thing.

(So when it comes to replacing the carbine-shaped hole in my gun rack, the money will go to an AR. Love the AK, AR's a better tool.)

Angus McThag said...

Even if you use Tier One parts they are somehow magically transformed into Tier Five unless assembled by a genuine Tier One Manufacturer.

I determined this by asking what breaks on the common FrankenAR and where I should buy parts. I was told that using the top shelf parts wouldn't change anything.

So, you must be a Tier One manufacturer!

I must be too since my Tier 2 parts have been going strong.

Sigivald said...

Angus: Weird, since Arfcom also has the "how to assemble your own lower" guides I always follow.

Tam said: I've assembled a lower while sitting on the futon watching television with no tools other than a punch and using a TV tray and my lap as work surfaces.

Lies! You also need a mallet for the roll pins, and ideally a wood block or equivalent for backing.

(And ideally roll pin holders. God damn roll pins.)

Mod_God said...

Just a little bit of insight from a CNC Machinist and Gunsmith in training:

The amazing thing about the AR was not particularly the machining, the machining of a %90 finished forging is actually quite menial and can be done on manual machines. It's the NC machinery that DARPA had a hand in developing during Stoner's design process that's truly the amazing thing. Even the barrel extension was still pretty doable by hand if you had access to EDM, which was gaining popularity at the time.

With the AR it's all about repeatability. Now instead of manual machinists putting these forgings through their steps and fitting everything, you're just clamping down a rough forging in the vice and pressing a button.

We have developed many more amazing manufacturing capabilities since then. The mills used back in Stoner's day to finish up the forgings were simple 3-axis mills. We now have 4,5 and even 6 axis machines that seem magical in comparison. If you ever get the chance go on youtube and find the videos that describe the manufacture of H&K Pistol slides.

As someone who pays close attention to the leaps and bounds made in manufacturing technology, I can say with certainty that the next iconic battle rifle will be even more ingenious given the seemingly magical things we're able to accomplish in creating useful parts out of plain blocks of metal, dust, and even gases.

Mod_God said...

Just for example, since I could not find the original video I had in mind, look here:

Guess the part!