AR15.Com Archives
 CNC Programs for Lower???
frozenny  [Member]
7/20/2004 4:23:45 AM EST
Hi Guys:

This may sound like a realy far out idea, but bar with me.

I am lucky enough to have access to a huge machine shop, complete with various CNC mills, lathes, etc. I've been putzing around making a number of neat widgets and thingmajiggys but now have my heart set on something more substantial. I've seen various 80% lowers, raw forgings, etc. I look at all this machinery and have visions of new lowers. Of course, there is a ton of cnc programming involved. For that matter I've seen a few websites where people have simply machined a lower out of bar stock, and these have an unbeleiveable finish...

Has anyone out there done this? If so, do you have cnc programs? I suspect I'd have some tweaking to do, but it would be a good start.
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Jservis  [Member]
7/20/2004 11:30:29 AM EST
http://www.roderuscustom.tzo.com/cgi-bin/ib3/ikonboard.cgi

check there. do a search. i know there is a guy that has done complete CNC'd lowers from billet aluminum and they looked great. he was also giving out the actually programs he wrote for the project, but i can't remeber his name. shouldn't be hard to find though. i wish i had those capabilities. hope this helps.
Jservis  [Member]
7/20/2004 11:35:50 AM EST
his name is jwh02017. he has programs for uppers, carry handles and all kinds of stuff. i think this is his website also detailing his builds http://www.cncgunsmithing.com
cncgunsmithing  [Team Member]
7/20/2004 11:43:46 AM EST
I'm not sure who you are talking about, but my user name on the Roderus forum is jwh02017. I have machined AR-15 lower & uppers from bar stock....along with AR-10 lowers. You can visit my website for all the details on my projects www.cncgunsmithing.com Below is a link to the programs and stuff for the AR-15 lowers.

Link for my programs/setup sheets and stuff from the Roderus Forum

How much programming & CAD/CAM knowledge do you have? Let me know if you have any questions, and I'll help you out the best I can.

Here is a pic of a polished AR-15 I made. On this rifle, I made both the upper and lower receiver.



Justin
frozenny  [Member]
7/20/2004 4:07:49 PM EST
Thanks! I have not opened the files yet (I'm at home on dialup). I'll unzip 'em at work. my CNC experience is very very limited. To be honest, I doubt I can pull this off. However, it is something to aspire towards.

I've been happy just putzin along with little dinky projects on a ProLight mill. I've been knockin out a few odds and ends projects and keep thinking about somethin "bigger". I may approach this AR lower as a series of smaller projects. (IE profile exterior as one project, EDM the mag well as another, etc) Rather than starting with bar stock, a rough forging may make for less machine time as it is kinda sorta already in the rough outline.

I've been playing with Frank DeHaas plans for various single shot rifles. Also been foolin' around with the idea of a repro BSA Martini Cadet single, or some form of break-type single shot pistol. All of these are relatively simple but are more or less intended as one-off hand fit projects. I'm starting from nothing. The AR is much more advanced but your files may give me a head start.

Thanks Much!

Frozenny
R14  [Team Member]
7/20/2004 4:12:18 PM EST
I thought you had to have a class 7 manufacture licencse to make a complete lower reciever, or any other type of reciever with a serial number.
viper5194  [Member]
7/20/2004 4:20:23 PM EST
dont think theres any requirments regarding a license if your manufacturing the lower for yourself and not for resale.
ar15zams  [Member]
7/20/2004 4:47:04 PM EST
My god, that rifle is beautiful. (and comming from an atheist, that's quite a comment!) That's an inspiration. I work in a machine shop, and will definitely attempt this project post haste.
cncgunsmithing  [Team Member]
7/20/2004 7:43:19 PM EST
I think if you took making the lower receiver in baby steps, you shouldn't have any problems. If you started with a forging, it would make it alot easier.

Making your own firearm is perfectly legal, as long as it's not ever for sale. It's all part of the 2nd Amendment :D "Right to keep and bear arms" Here is a link from the ATF's website...look under section A7... www.atf.gov/firearms/faq/faq2.htm

Justin

Jservis  [Member]
7/21/2004 11:51:52 AM EST
i have cncgunsmithing's lower set up blocks and they were invaluable. im about to finish mine today and will post picks. i did everything on mine with a drill press and some clamps. a cheap ass craftsman drill press. cncgunsmithing, you hvae inspired me to add CNC Machining to my engineering classes for next year. very amazing work.

Jservis
R14  [Team Member]
7/24/2004 8:45:03 AM EST

Origionaly posted by viper5194:

dont think theres any requirments regarding a license if your manufacturing the lower for yourself and not for resale.




I see. I might have to try something like this. Thanks for the info.
imcoltsguy  [Member]
7/24/2004 11:17:38 AM EST


A beautiful rifle. You are definitely well above the hobby gun builder class.

model927  [Member]
7/24/2004 12:33:51 PM EST
I saw your site,man you make some real nice receivers,Do you have the ability to sell them yet?if you ever start manufacturing them, I will be the first to buy a lower from you.The work looks great.
cncgunsmithing  [Team Member]
7/25/2004 5:15:02 PM EST
Thanks ....I'm glad you guys like the work I've done.

Sorry, I can't sell any receivers right now. I'm still working on getting approved by the ATF to sell my version of the 80% AR-15 receiver. After the AWB sunsets, I'll be pushing harder to get my receiver approved. I kinda think the ATF may be dragging their feet because of this ban.

Justin
utahcybercowboy  [Member]
7/28/2004 5:02:55 PM EST
What type of aluminum does one use for building a lower on a CNC mill? How does this compare in stregnth to forged or cast lowers?


Steve

edpmedic  [Team Member]
7/28/2004 5:31:34 PM EST
Jservis...I have a question when you use your drill press wasn't there to much radial runout? I have a Craftsman 17" floore drill press with the 16 speed and 5/8 chuck.
I was going to try one of the 0% lowers I got off the EE but I don't think the tolerances will stay tight enough. I use to do Tool and die work and als have a Automotive mechanical engineer degree. That was before CNC was around or just starting with Sunstrad machines. I was always taught a drill press is for drilling.

I did use the drill press on my HK usc to make the slotted vents and thats when I realized it might not be a good idea to do it and that was on plastic. Yea I checked to make sure everything was tight and has much runout out of the thing.

I have been doing this project slow and still looking for a mill or a lathe mill combo setup before I proceed.

frozennyThe Roderus Custom Gunworks and Private Ryan are who I started e-mailing also jwh02017 and the tannery shop have given me lots of info along with his site. Get good clamping devices and good bits, taps, and etc. I see and hear alot of people doing it with a press and also files. IMHO that aint for me.
Good luck and keep me informed
asltrfl  [Member]
7/28/2004 6:56:51 PM EST
I too, work with Haas milling centers, Chiron 20 position 4 axis milling centers, and an assortment of CNC lathes, knee mills, manual lathes, etc. We need the program!! Who knows where to find the RIGHT program for the receivers? We are already in the parts business and getting a class 7 is not a problem. If anyone can help, let me know. Can perhaps make a deal.
cncgunsmithing  [Team Member]
7/28/2004 8:34:44 PM EST
utahcybercowboy: For my receivers, I used 6061 T6 aluminum. It's much cheaper than 7075 aluminum. I finished the receivers with a black anodize finish. I have put more than 1000 rounds through one of my lowers, and I can't see any wear what so ever. Most of the 0% forgings you'll see out there are made of 7075, but I think that's kinda over kill......but forgings are to mil-spec (as for the material type) and I think the military kinda done an over kill in this area. But a receiver may last a little longer if it was made of 7075. I think you'll be good using either 6061 or 7075.

You might be able to complete a 0% forging with a drill press, but you need to make sure your drill press is really beefy.....since there is alot of machining to be done on a 0% forging. Your best bet, if you just have a drill press, is to start with a 80% receiver.....usually those just have the drilling left to do.

asltrfl: You want a deal on the AR-15 lower programs? how about FREE!!! I posted all my programs on the Roderus forum. AR-15 lower programs If you find the programs and the info on my website useful, perhaps you could make a donation to my website to help keep it up and running so other people in the future can have access to this info.....but if not, they are still FREE

Justin
Winston_Wolf  [Team Member]
7/28/2004 8:38:50 PM EST

Originally Posted By utahcybercowboy:
What type of aluminum does one use for building a lower on a CNC mill?




... My first choice would be 2024-T351 Plate, has a high copper content, very tough shit
xtremist  [Member]
7/30/2004 6:10:47 PM EST
I have a few questions about doing this, because it sounds VERY interesting and I hadn't ever even considered this a possibility.

1) What are the starting measurments for the aluminum block you start with? I've been trying to find different places to pick this up and the biggest challenge so far is finding many places that offer it deep/tall enough. I can measure my current RRA lower, but I have no idea how much "excess" you need to have...

2) What are the chances or reversing the design to make a left-handed AR? I'd guess reversing the design would be fairly easy, but I'm worried the other internals wouldn't operate correctly. For instance brass ejection, mag release, safety, etc... I'd really love to have a lefty AR, especially a custom one like this.

Any ideas?
Winston_Wolf  [Team Member]
7/30/2004 6:24:48 PM EST

Originally Posted By xtremist:
I have a few questions about doing this, because it sounds VERY interesting and I hadn't ever even considered this a possibility.

1) What are the starting measurments for the aluminum block you start with? That largely depends on which machine you post the program to and considerations like how many set-ups, tool changes and how many axes your machining center has. OTOH, if your doing a free-standing set-up on a knee mill, you just need enough to "clean up" and clamp. If a knee mill is your choice, 8"X4"X1.5" is a doable envelope. I've been trying to find different places to pick this up and the biggest challenge so far is finding many places that offer it deep/tall enough 4" X 1.5" extruded plate is a common shape, readily available in most big cities. I can measure my current RRA lower, but I have no idea how much "excess" you need to have...

2) What are the chances or reversing the design to make a left-handed AR? No problem with the lower receiver, it's the upper where you're going to run into some challenges. I'd guess reversing the design would be fairly easy, but I'm worried the other internals wouldn't operate correctly. For instance brass ejection, mag release, safety, etc... I'd really love to have a lefty AR, especially a custom one like this.

Any ideas?

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