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Discussion Starter #1
...or "I mighta bit off a little more than I can chew"....



So... who thinks I'm gonna get killed when she gets home, who thinks I'm not gonna be able to figure out all the machining to get it done, and who isn't even sure from the pic, what it is?

:eek:
 

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I can't tell what it is. My gut feeling is something AR-related...

I'd need you to blow the cleaning fluid off of it, and take another pic....
Or I could just wait until Gil or RedHorseyGuy posts and says "Hey Fawktard, that's a ________ " :laughing:
 

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Discussion Starter #6
Sorry, no, I have no prizes. :(

AR-10 lower-to-be.
Gotcha is, I've never actually touched an AR-10, much less handled a stripped lower. Kinda flying blind, but at least scrap aluminum isn't very expensive.
 

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Fistful of Boomstick
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funny, I was at work using the bridgeport for something nifty I am making and saw a huge chunk of aluminum that I thought would make a nice milled AK receiver :laughing:
yes aluminum, with steel rail inserts :D

but then i was distracted by something else shiny
 

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Sorry, no, I have no prizes. :(

AR-10 lower-to-be.
Gotcha is, I've never actually touched an AR-10, much less handled a stripped lower. Kinda flying blind, but at least scrap aluminum isn't very expensive.
Did you get the CAD file from CNCmachine gunworks or whatever their website is?
 

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Discussion Starter #9
Did you get the CAD file from CNCmachine gunworks or whatever their website is?
Yeah, CNCGuns.com (used to be CNCGunsmithing.com); downloaded the model from there, then tweaked it a bit, and fed it to my mill. Unfortunately, my mill is nowhere near as smart as the one the guy on CNCGuns uses, so this will probably take me a fair bit longer, and involve a lot more setups, than his. But I like making stuff, so it's all good.
 

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Yeah, CNCGuns.com (used to be CNCGunsmithing.com); downloaded the model from there, then tweaked it a bit, and fed it to my mill. Unfortunately, my mill is nowhere near as smart as the one the guy on CNCGuns uses, so this will probably take me a fair bit longer, and involve a lot more setups, than his. But I like making stuff, so it's all good.
What on it did you tweak?? And just out of curiousity About how much time would it take a decent CNC to do this??? I'm thinking of having a local machine shop make an 80% billet for me
 

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Discussion Starter #11 (Edited)
What on it did you tweak?? And just out of curiousity About how much time would it take a decent CNC to do this??? I'm thinking of having a local machine shop make an 80% billet for me
I lowered the trigger guard floor and made it integral, extended the magwell accordingly, and that's about as far as I've gotten so far. Since my CNC capabilities are closer to 2D than true 3D, I'm kinda having to design on the fly as I figure out what will work with my mill, so there'll probably be some more changes yet to come.

Time? Probably well more than the couple hours you'd get for the $200ish that the Armalite 100% lowers, sticker for, and could very well still be more than the $400 that the billet DPMS one goes for. By the time I get done with it, I'll have a minimum of nine setups (right side, left side, top, bottom, buttstock, pistol grip, magwell, front end, buffer retainer) into it, and while a better machine (and a better operator) could crank this out a lot faster, I'd have to think that if you have to pay somebody to mill on one of these, you're money ahead to just buy a complete one. I'd bet Aloharover can get you one fairly quick-n-easy, and probably cheaper than the DIY thing too.

Granted, most of those setups are for minimal stuff; the "bottom" setup is two holes, the "buttstock" setup is a contour, three holes, and a tap, "pistol grip" is one hole and a tap, "front" is one slot and one hole, "buffer retainer" is one hole... but conversely, it looks like "right side" is probably going to be six entire programs by the time I get through with it.

And it's a good thing scrap aluminum is reasonably cheap, 'cause I just wasted the first one of these. :(

I'll probably go ahead and finish out a decent portion of my screwup, just for the sake of making sure that the other sides worth of programming, actually work right. I got enough aluminum to make four, but I'd really rather not scrap out more than one.
 

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you better engrave someting funny or cool into the sides or I will be pissed :laughing:
like the "fire" and "safe" should read "OFF" and "BACON" or something :flipoff2:
 

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Discussion Starter #13
OK, so that was really weird... I had dreams of writing G code. :eek:

But on reflection, yeah, I f'd it up, but I think I can save it. It'll just mean more machine work; center has yet to be defined off of anything that I haven't machined, and if I machine it down another 1/8" or so, it just means center is a little closer to the table in this setup. Since the left side heights will be cut based on the height of the right sides (the right side, semi-obviously, is what I'm starting with), it doesn't matter all that much where the right side is in the block, just as long as there's enough block to still contain the part. Fortunately, I started with a 2" thick block for a 1.6" wide part.

My mill isn't smart enough to engrave. I'll do what I can with the vinyl cutter to try and bring the funnay anyway, though.
 

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OK, so that was really weird... I had dreams of writing G code. :eek:

But on reflection, yeah, I f'd it up, but I think I can save it. It'll just mean more machine work; center has yet to be defined off of anything that I haven't machined, and if I machine it down another 1/8" or so, it just means center is a little closer to the table in this setup. Since the left side heights will be cut based on the height of the right sides (the right side, semi-obviously, is what I'm starting with), it doesn't matter all that much where the right side is in the block, just as long as there's enough block to still contain the part. Fortunately, I started with a 2" thick block for a 1.6" wide part.

My mill isn't smart enough to engrave. I'll do what I can with the vinyl cutter to try and bring the funnay anyway, though.
What post do you use? I could write the code for engraving for you.......
 

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Discussion Starter #15
What post do you use? I could write the code for engraving for you.......
I'm using Powerstation Xpert as a post processor.

The machine is a 1981 Wells-Index with an early Bandit controller; it'll only accept raw oldschool G, no special stuff.

On the plus side, though, I did just find out that it'll accept just over a thousand lines of code... I was under the impression before that it'd choke at 256, so this is good news.

I've actually been experimenting with exploding text in AutoCAD, turning it into lines and arcs and whatnot, and if I explode it and then postprocess it to cut on center, it should work reasonably as ghetto-engraving. Artwork is out the window, though; just too complex.

And it looks like, if I go back to the original part height, I can fix my earlier screwup. An omission of one line of code, resulted in my milling-off my low mag release fence, but shifting part center again should have that fixed. No more screwups on this one though, or I won't be able to mill out the fire control group pocket any more. :eek:
 

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Discussion Starter #19 (Edited)


A little more progress, and a little more apparent as to the trigger guard reshape that I referenced before.

I've been making more progress at fine-tuning my machine code and machining sequences, than at actually carving on this chunk of aluminum, over the last couple days.

I'm now more or less done with what I can (and want to; I'm deliberately leaving the trigger guard over-wide for the moment) actually do from this side of the receiver for now; I need a long-reach relatively small-diameter end mill (1/4 to 5/16 diameter) to cut the mag release button well, and I have no such animal, and can't even get one to ship before tomorrow.

In retrospect, I probably should've reshaped the mag button fence to resemble the KT Ordnance AR15 style; would've been a ton easier to cut that shape than trying to mimic the Armalite forging that the CNCGuns solid model looks like. Or maybe get a smaller diameter chamfer mill so that I can do finer work with it.

Edit: Scratch the long 5/16" endmill thing. Patience (and the presence/disposability of my buddy Dave's too-dull-to-cut-medical-grade-stainless throwaway tooling) owns me. Mr Endmill, meet Mr Grinder. Reduced shank endmill = long enough reach to mill out the mag button well. :)

Editagain:
One more pic, out of the mill and chopped off the excess garbage--most of the remaining junk will end up milled off in the process of profiling the left side, a little bit of it, I'll have to reprofile the part from the left side. No biggie, other than that it's ugly right now.

 

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Discussion Starter #20 (Edited)
Well, I officially suck at machine work... while trying to profile the left side today, I milled off the area where the two little nubs that hold the bolt catch retainer pin, go through. :(

Pic's not great, but you can kinda see that the bolt catch nubbins are missing. :( Fixed that in the code, next try won't be so bad.

 
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