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Author Topic: How hard to build an 80% lower?  (Read 649 times)

JT

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How hard to build an 80% lower?
« on: April 03, 2020, 07:08:39 am »
Thinking of doing an 80% lower out of aluminum or poly. I have a drill press. How hard is it and do I need some other tools?

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    patkelly4370

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    Re: How hard to build an 80% lower?
    « Reply #1 on: April 03, 2020, 07:57:58 am »
    An AR lower? It's not difficult, but it is mildly time consuming and messy.
    I used a commercially available jig and a router instead of my drill press.
    Drill press is designed to push a bit into material.
    Milling a lower, the force is lateral. So a router was better for me.

    Sent from my SM-G955U using Tapatalk


    CMore

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    Re: How hard to build an 80% lower?
    « Reply #2 on: April 03, 2020, 02:22:53 pm »
    How difficult is it? 
    Well this is an interesting question to give and receive.  I like to compare it to a brain surgeon and auto mechanic.  If they ask each other how hard their job is both might reply there is a lot of learning but, after you start doing it,  no big deal...   I am sure you would NOT want me to do your brain surgery but, you might be OK with me working on your gun.  The short answer is if you are careful and mechanically inclined you should have no problem.  I have seen a few guys who were not and they still have functioning guns and I have seen a few 80's turned into 100% junk too. Worst case it should be a fun learning project so good luck.


    What to do it with...
    It is certainly doable on a press and a press will work well on drilling holes and cutting up and down.  One draw back with a press is rigidity. The shaft unlike a mill will move around a lot when you put a side load on it so, if you cut a pocket you will drill it out. What Pat said is a good idea and I have seen several made this way. The router is real good for hogging out the pocket areas. I think a combination of drill and router is the way to go.  As Pat said having a jig designed for how you are going to cut it will make it much easier.   


    How easy can it be?
     My last 80% took 4 minutes from beginning to end on a CNC machine. I have also designed and made them from a solid block of aluminum when I was working for a manufacturer.

    Jump right in and don't be discouraged if it doesn't work the first time,  I know far more guys who made a mistake on the first one than I know who did the first one perfect...   Just go for it...
    K1CJM

    patkelly4370

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    Re: How hard to build an 80% lower?
    « Reply #3 on: April 03, 2020, 05:40:38 pm »
    I will also clarify that I've been mechanically inclined all my life.
    I've  never particularly drawn to the AR. I decided to get one because California didn't want me to have one. At that time CA hadn't yet gone completely tyrant on 80% yet, so I went that route.
    Assuming I would bungle the first one, I bought 2 blanks.
    First one came out fine and functions as intended. Now I had another blank.
    So I milled that one intending for it to be a dedicated 22lr.
    Then just for fun I did a 3rd 80% polymer lower which became the 22lr.
    So now I have 3 that I seldom shoot because I'm not AR-centric. Nothing against them, just not my favorite.
    All 3 have functioned flawlessly and are extremely accurate (I attribute that to the uppers)

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    Clifffalling

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    Re: How hard to build an 80% lower?
    « Reply #4 on: April 03, 2020, 06:15:34 pm »
     80 % arms has it down.  Great jigs that, with the right router,  patience and care will turn out great lowers. Of course, if you can afford a table top cnc... you in business brother.  Err, not business... hobby i mean.😁
    Flagtaff: Poverty with a view.

    JT

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    Re: How hard to build an 80% lower?
    « Reply #5 on: April 04, 2020, 07:48:32 am »
    I have watched several videos on Utube and most look very crude. There was one that used a plate for a router to finish the well. It looked about the best. Looking at the cost of the vice, jigs and bits along with the lower it is a lot cheaper to buy a finished lower. The only advantage is not having a serial number or if you were building a bunch of them. I am not that fond of the AR either all though it is growing on me. Polymer lower kits came complete with jigs and tools for about $75. I can buy an aluminum stripped lower for that including the transfer. I can buy a complete polymer lower for $120 including the transfer.
    I have a piston AR15 with a red dot that works well for me. AR15 has too much forward weight for my wife to handle. We mostly shoot the 15-22's and AR9 pistol. My wife decided she liked the AR9 (it does not have the forward weight) so I was thinking of putting together another one. I can buy an AR9 pistol complete for $500 otd and I dont think I can build one for that.

    CMore

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    Re: How hard to build an 80% lower?
    « Reply #6 on: April 04, 2020, 11:03:22 pm »
    Cost wise the 80% is going to be a lot more expensive. If you shop around you should be able to pick up a stripped lower for as low as $50.

    Unless you are lucky enough like myself and have a machine shop at your disposal.
    K1CJM

    patkelly4370

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    Re: How hard to build an 80% lower?
    « Reply #7 on: April 05, 2020, 01:22:19 am »
    The lower blank costs less than a stripped lower + dros.
    Then there's the cost of the jig which is divided by the number of lowers milled with it. Or you can sell it.

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    ShooterReady

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    Re: How hard to build an 80% lower?
    « Reply #8 on: April 06, 2020, 11:53:59 pm »
    I've never seen a completed 80% lower that didn't look like it was completed by a drunk blind person with a wobbly router. 

    Machining should be left to professionals. 
    Have a good 'un

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