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80% Milling Info (Page 5 of 5)
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Originally Posted By maggiethecat: I meant polymer, dont know why i wrote P-80. Originally Posted By maggiethecat: Originally Posted By backbencher: Polymer AR 80%. Not a P80. Drop a polymer AR lower in a thumbhole stock & it should hold up. I just need to learn how to do it instead of casting a lower from epoxy. I meant polymer, dont know why i wrote P-80. EP Armory's are pretty cheap, no reinforcing metal like Tennessee Arms? Just cast nylon. They used to have a bulk buy deal that got em down to $12 each, IIRC. Now they're $25 before shipping & tax. You're probably not saving money by the time you buy a Vism thumbhole, but you're not cutting on the Vism. If you screw up, you throw away a $25 learning experience vs a $50 aluminum one. |
Death to quislings.
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Originally Posted By maggiethecat: Using OP's numbers and brand new endmills I cut out a gorgeous receiver. Pocket is a couple thou narrow for the trigger (2 different ones) and a few thou shy on the fwd edge, hammer wont rotate. How much material did you cut in your last pass? 1.250 DOC plus enough stick out to clear the RE and I get a lot of deflection trying to clear more than .005 |
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Originally Posted By AFCarbon15: How much material did you cut in your last pass? 1.250 DOC plus enough stick out to clear the RE and I get a lot of deflection trying to clear more than .005 I ran in one cut, so .065. seems I had some deflection. I put them back in, ran the same numbers but got some chips. All good now, parts fit well. finishing passes are a good thing. EDIT- brain dump, it'd be half of the .062 |
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Originally Posted By maggiethecat: I ran in one cut, so .065. seems I had some deflection. I put them back in, ran the same numbers but got some chips. All good now, parts fit well. finishing passes are a good thing. So I cut to the final pass domensions with a 3/8 rougher. That leaves .031 to clean up with a finishing end mill. I then cut all but .005 short with the finisher is one pass, then run the final dimensions in 2 passes. Usually don't cut anything in the seconds, but it saves a lot of setup time if I had to do it again. Also, I always check with a hammer or trigger before removing from the mill. |
A firearm is like a parachute, if you need one but don't have one, you'll probably never need one again. IG @jimstagramguns
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Originally Posted By AFCarbon15: So I cut to the final pass domensions with a 3/8 rougher. That leaves .031 to clean up with a finishing end mill. I then cut all but .005 short with the finisher is one pass, then run the final dimensions in 2 passes. Usually don't cut anything in the seconds, but it saves a lot of setup time if I had to do it again. Also, I always check with a hammer or trigger before removing from the mill. yeah, brain dump, forgot to divide the difference by 2, so last pass was .031, not .062 |
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Originally Posted By backbencher: This is the link provided by the Flat Spot for their weld-together DPMS pattern steel lowers: http://www.theflatspot.net/uploads/6/9/0/0/6900641/dpms_308.pdf 
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"Whoever makes himself great will be made humble. Whoever makes himself humble will be made great." -Jesus
"if it can be destroyed by the truth, it deserves to be destroyed by the truth" - Linus from Charlie Brown
"if it can be destroyed by the truth, it deserves to be destroyed by the truth" - Linus from Charlie Brown
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Originally Posted By OG1: Holy poop....that link has changed over the years lol. It is a porn link now lol. My co-worker was entertained by my fumbling to close it. Originally Posted By OG1: Originally Posted By backbencher: This is the link provided by the Flat Spot for their weld-together DPMS pattern steel lowers: http://www.theflatspot.net/uploads/6/9/0/0/6900641/dpms_308.pdf Holy poop....that link has changed over the years lol. It is a porn link now lol. My co-worker was entertained by my fumbling to close it. Lol, that's 8 years old. I got warnings from my browsers to not even connect. Thanks, I went back & removed the link. I suppose given enough time, all links ultimately resolve to porn websites. |
Death to quislings.
| I’m having an issue with a polymer 80% lower. I have a 5dtactical jig that my JMT polymer fits into. The problem I have is that my compact router has a 10k-30k speed range while JMT recommends a speed range of 600-800 rpm using their plastic jig. Is there any reason or advice on using my router at 10k as long as I go shallow and don’t melt the polymer? |
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Originally Posted By RPGMan: I’m having an issue with a polymer 80% lower. I have a 5dtactical jig that my JMT polymer fits into. The problem I have is that my compact router has a 10k-30k speed range while JMT recommends a speed range of 600-800 rpm using their plastic jig. Is there any reason or advice on using my router at 10k as long as I go shallow and don’t melt the polymer? I think 10k will melt it really quickly. Harbor Freight sells a router speed control. That would be a cheap option to get you down to a reasonable speed. |
A firearm is like a parachute, if you need one but don't have one, you'll probably never need one again. IG @jimstagramguns
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Originally Posted By AFCarbon15: I think 10k will melt it really quickly. Harbor Freight sells a router speed control. That would be a cheap option to get you down to a reasonable speed. |
"Whoever makes himself great will be made humble. Whoever makes himself humble will be made great." -Jesus
"if it can be destroyed by the truth, it deserves to be destroyed by the truth" - Linus from Charlie Brown
"if it can be destroyed by the truth, it deserves to be destroyed by the truth" - Linus from Charlie Brown
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Originally Posted By Blowout: Nice to see this thread hasn't fallen into the archives. Lots of good information buried in it. I still average about one email per week asking for details or clarification on something Posted here. And I still cut into another here and there. Last week's AR308! Attached File |
A firearm is like a parachute, if you need one but don't have one, you'll probably never need one again. IG @jimstagramguns
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One additional detail or recommendation I would like to add.... For anyone that is contemplating using a super safety type FRT, you'll need to remove material behind the safety hole for the lever. Example...the red area needs to be removed for the lever to have full travel in SS mode. Basically your just moving the pocket behind the safety farther back. Attached File |
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Originally Posted By IdahoPCCinc: One additional detail or recommendation I would like to add.... For anyone that is contemplating using a super safety type FRT, you'll need to remove material behind the safety hole for the lever. Example...the red area needs to be removed for the lever to have full travel in SS mode. Basically your just moving the pocket behind the safety farther back. https://www.ar15.com/media/mediaFiles/517689/ar15print_jpg-3563602.JPG You're a couple of steps ahead of me. I have run FRT's in my cut lowers, but I haven't gone to a super safety, yet. I did have to push the pocket another .020 forward for one trigger pack, but otherwise no issues. ETA: I'm stoked you guys are still using this thread to spread knowledge on the topic. Maybe one day, we can make it look easy enough everyone will do it. |
A firearm is like a parachute, if you need one but don't have one, you'll probably never need one again. IG @jimstagramguns
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Originally Posted By IdahoPCCinc: One additional detail or recommendation I would like to add.... For anyone that is contemplating using a super safety type FRT, you'll need to remove material behind the safety hole for the lever. Example...the red area needs to be removed for the lever to have full travel in SS mode. Basically your just moving the pocket behind the safety farther back. https://www.ar15.com/media/mediaFiles/517689/ar15print_jpg-3563602.JPG i'm not sure that's 100% the same for every variation. meaning, for the super safety it really wants a low shelf lower, so if you cut for high shelf then yes, there is a clearance issue, which you can solve by either moving out some material or switching to low shelf. but some devices want a high shelf and others a m16 cut, so i wouldnt say that would be automatically how i'd cut the pocket without considering the type of FCG i'm using. |
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Originally Posted By AFCarbon15: ... ETA: I'm stoked you guys are still using this thread to spread knowledge on the topic. Maybe one day, we can make it look easy enough everyone will do it. |
Disclaimer - OP is bad at knowing things, and might catch on fire.
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Vet - Op MMAMA
Every other species kills off their stupid......we cater to them. -- spin-drift
Nobody ever called 911&said I just did something smart. -- TheFlynDutchman
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Originally Posted By Amish_Bill: Chatting with OG1, Reading the 0% booklet, and now this thread... I'm getting more and more eager to get my tools installed and ready so I can join the fun. Lots of good guys around here with a ton of good information. I've been following your machining threads too. Welcome to the adventure. There's a lot of good information in my other thread too. My Zero Percent Thread |
A firearm is like a parachute, if you need one but don't have one, you'll probably never need one again. IG @jimstagramguns
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Originally Posted By AFCarbon15: Lots of good guys around here with a ton of good information. I've been following your machining threads too. Welcome to the adventure. There's a lot of good information in my other thread too. My Zero Percent Thread that is a great thread! - i've always wondered - terminology wise is a raw forging a zero % or a 20% or what is the right term to differentiate a billet from a forging? |
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So a billet is just that. It's not a receiver, as it could be anything. A raw forging is headed down the road to be a receiver, but 0% of the machining ops have been completed. Thats my version of the story anyway. Not sure if I even heard the term 0% before I started using it. But I can't be the first. |
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I dont know if these guys own the terminology either - but i have seen this phrasing used before elsewhere also; 80% arms 0% Billet AR-15 Lower Receiver  "We are pleased to offer the finest 0% billet AR-15 lower receivers in the world. What is a zero percent lower you ask? As the name suggests, it's a lower receiver that is zero percent complete. In other words, solid aluminum bricks. Our lowers start off in the form of these billet aluminum blocks and are machined to 80% completion on our state-of-the art 5 axis CNC mills. These solid aluminum blocks are heavy and have very sharp edges. They could make a good weapon if thrown at an attacker." 20% Lower - Blank AR-15 Lower Receiver Forging  "This blank forging is the precursor to a forged AR-15 lower receiver. No milling operations have been completed on it. It's more complete than our 0% Lower Receiver, but less than 80% complete, so we're calling it a "20% lower receiver". This blank AR-15 lower receiver is a Cerro Forge lower forged from 7075-T6 aluminum." |
80% Milling Info (Page 5 of 5)
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