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Author Topic: 80% Arms brand 80% AR lower receiver review  (Read 6876 times)

Jefe

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80% Arms brand 80% AR lower receiver review
« on: August 17, 2014, 09:52:20 PM »

Discuss the review of this lower posted here:

http://80percents.com/80_arms_lower_review.html
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DamMan

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Re: 80% Arms brand 80% AR lower receiver review
« Reply #1 on: February 16, 2015, 05:58:33 PM »

I watched all the available videos, read the instructions multiple times and still botched my first lower so I can't comment directly on the 80% Arms lower.  What I can comment on is 80% Arms fantastic customer service.  80% is replacing my lower at half price, provided me with tremendous phone support and has already shipped my lower today, the same day I called in.  I am definitely an 80% Arms customer for life!
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Jefe

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Re: 80% Arms brand 80% AR lower receiver review
« Reply #2 on: February 16, 2015, 06:45:40 PM »

What did you do wrong on the first lower?
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DamMan

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Re: 80% Arms brand 80% AR lower receiver review
« Reply #3 on: February 16, 2015, 06:56:29 PM »

Let the end mill slip when I moved it a little further out of the collet for the last few passes, causing a hole in the bottom of the lower.  Even before that, I somehow got scoring on the trigger pocket guide where the end mill smooth shank was rubbing it.  Once the scoring started, I think the end mill got too hot and caused uneven milling on the sides of the lower.  80% Arms thinks it is possible my router has a bad bearing and that would also cause the sloppy milling.  I think a bad bearing could also cause overheating and scoring of the template.
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Jefe

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Re: 80% Arms brand 80% AR lower receiver review
« Reply #4 on: February 17, 2015, 10:10:21 AM »

I'd put my bet on a bad router as well. It seems like the collet didn't keep the end mill tight and the end mill must have been slipping around to cause that other damage. I don't know why else a smooth end mill shank would wear out that hard anodized surface. That rear pocket looks a little close to the buffer retainer hole too.
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DamMan

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Re: 80% Arms brand 80% AR lower receiver review
« Reply #5 on: March 01, 2015, 08:31:37 PM »


New router, new template and new 80% lower.  Thanks to 80% Arms for the no cost replacement template and the 1/2 price lower.  As the picture hopefully shows, things went much better this time.  No unintended holes.  What looks like a beveled edge at the top is an optical illusion.  The only problem is the project took 5 hours!  I tried increasing my depth of cut 1/4 of a hash mark or approximately 1/16'" each pass with very light cutting fluid but still felt I had chatter and didn't want to knock a hole into the mag release channel.  I dropped down to 1/8 of a hash mark or approximately 1/32" and used lots of cutting fluid for what felt like smoother cutting.  Did I go the right way to reduce chatter?  Instead of reducing to 1/8 of a hash mark, should I have increased to 1/2 of a hash mark?  I was so nervous after my first disaster, I may have been overly cautious.  I know it took way too long to complete the lower but I am happy with the result.
« Last Edit: March 02, 2015, 03:44:23 AM by DamMan »
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Jefe

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Re: 80% Arms brand 80% AR lower receiver review
« Reply #6 on: March 02, 2015, 10:11:57 AM »

It's better to take off less material at a time than more so you went the right way. Really 1/3 to 1/4 of a hash mark should be all you need to go for a smooth cut. The top right edge looks like it is wavy. Do you know what may be causing that? What RPM do you have the router set at? Where did you get your end mill?

Have you tried repairing your first lower? Maybe put some tape on the underside of the trigger pocket and then add some JB Weld to the trigger pocket bottom. Let it cure for a day or two then mill out small increments of the trigger pocket bottom.
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DamMan

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Re: 80% Arms brand 80% AR lower receiver review
« Reply #7 on: March 02, 2015, 03:01:41 PM »

My new router is the PORTER-CABLE PCE6430. It is single speed 31000 RPM. I don't know why the right edge looks odd in the pic because it is fine. My only disappointment was the time it took.
Yes I did repair the original lower for practice. I was able to fix the hole in the bottom but not the front of the trigger pocket. It works fine but I am much happier with this second attempt, although I haven't installed a LRPK yet
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Jefe

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Re: 80% Arms brand 80% AR lower receiver review
« Reply #8 on: March 02, 2015, 09:27:13 PM »

Edited: I was wrong about the speed I run my router. I thought the speed control was giving me the RPM in thousands but it's just a relative speed. I run mine around 18-20k RPM based on the place I set the speed control.
« Last Edit: March 05, 2015, 08:01:25 PM by Jefe »
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DamMan

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Re: 80% Arms brand 80% AR lower receiver review
« Reply #9 on: March 02, 2015, 11:07:28 PM »

Interesting. Both my original Dewalt and the new Porter-Cable are 80% Arms recommended routers.
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DamMan

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Re: 80% Arms brand 80% AR lower receiver review
« Reply #10 on: March 06, 2015, 09:21:43 PM »

Edited: I was wrong about the speed I run my router. I thought the speed control was giving me the RPM in thousands but it's just a relative speed. I run mine around 18-20k RPM based on the place I set the speed control.
Thank you for the update, I bought a variable speed control for my router and as soon as I receive my next lower from 80% Arms, I will be experimenting.  Thank you for this forum and advice.
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Jefe

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Re: 80% Arms brand 80% AR lower receiver review
« Reply #11 on: March 07, 2015, 08:58:50 AM »

Please report back on your experience at these lower speeds. The next time I do one I will try it at higher speeds and see what I encounter.
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tresguey

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Re: 80% Arms brand 80% AR lower receiver review
« Reply #12 on: June 27, 2016, 01:08:20 PM »

I am new to the forum here and am about to build my first project. I do have the 80% Arms lower on radar, but looking at the images in this thread I see porosity after some milling. I thought these lowers were billet. if there is porosity in the one in the image tells me it's a die-casting. Or are my eyes just off and there is no porosity.
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Jefe

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Re: 80% Arms brand 80% AR lower receiver review
« Reply #13 on: June 27, 2016, 01:43:06 PM »

I am new to the forum here and am about to build my first project. I do have the 80% Arms lower on radar, but looking at the images in this thread I see porosity after some milling. I thought these lowers were billet. if there is porosity in the one in the image tells me it's a die-casting. Or are my eyes just off and there is no porosity.

They're billet. Welcome to the forum!
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