80% AR lower tips?

[Texas by God]

I'm going to build a couple of these in the future. I have the 80%Arms gen 2 jig, bits, two 80% lowers and all the stuff to make 2 5.56 ARs. Any tips for a first timer? This project kind of fell in my lap so here we go.
Thanks in advance!

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[trails4u]

Drill press and patience. And don't drill quite as deep as the jig....I mean not by much. Will be much cleaner with the endmill on the router as you won't have the drill tip dimples left behind....

[rancher1913]

use a quality jig, the ones that you drill and dremil out are crap for a hobby guy to get right. I got the 5d tactical that uses a router and if I take my time you can not tell it from a factory one.

[Texas by God]

Yes, this one uses the router. Good stuff, any videos you recommend?

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[Sig556r]

lotsa patience, measure twice/cut once...

[cwtebay]

I'm a little different I guess, I like the drill method. I use the included plate but then drill between the large holes with a 1/16" bit until no more holes will fit. Then I use a router to finish the material removal. I use headlight buffing compound to polish. There was a video on this on YouTube but I think it must have been taken down since I last used it.

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[cub45]

Use a milling machine, you have total control and can see what you are doing.
I've done a few.
kurt get a long 2 flute tool

[cub45]

oops, tried to edit, should be gap between kurt and the get 2 flute tool stuff

[merlin101]

Short of a milling machine the router method is next in line. When using the router chips fly EVERWHERE! After doing the first one I used a cheap harbor freight blue tarp and cut a hole in the center big enough to fit over my vice, the tacked up the back and sides. That made clean up a breeze. Cut slowly and carefully wear PPE! Make sure you check the collet is tight especially for the final cut they seem to want to loosen and the bit slides out making a deeper cut ending with a cut all the way thru the trigger area! Pay special attention to the difference in depth, notice that the rear is not as deep. Don't forget gloves, al. slivers are small and hard to get out.

[cwtebay]

Short of a milling machine the router method is next in line. When using the router chips fly EVERWHERE! After doing the first one I used a cheap harbor freight blue tarp and cut a hole in the center big enough to fit over my vice, the tacked up the back and sides. That made clean up a breeze. Cut slowly and carefully wear PPE! Make sure you check the collet is tight especially for the final cut they seem to want to loosen and the bit slides out making a deeper cut ending with a cut all the way thru the trigger area! Pay special attention to the difference in depth, notice that the rear is not as deep. Don't forget gloves, al. slivers are small and hard to get out.Excellent point, long sleeves and gloves (and something to keep them from going down your neck!!!) and face protection are definitely necessary. I built a mount for a shop vac on my vice which helps a ton. Good quality cutting oil helps with keeping the chips under control also.

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[ScrapMetal]

I haven't used the jig/router method and have only done it on my mill. The number one thing (after safety) that you need to make sure of is having a solid, stable vise to hold the work.

I made a set of vise jaws to hold mine. There are some pics at the start of my first 80% build at AR lower build (http://www.arcaneiron.com/phpBB3/viewtopic.php?f=19&t=28)



-Ron

[Texas by God]

It turns out that the router adapter is not present but Midway to the rescue. No directions either but the video is good.
I don't have a mill- yet.....

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[justashooter]

parts kits from palmetto state are reliable lately.

[nun2kute]

WHOA !!!! Scrapmetal Dude !!!! You stopped Waayyyyyyy to soon with the pictures. ! We need to see that whole process, step by step. With NFL instant replays. PLEASE !! [smilie=s:

[ScrapMetal]

WHOA !!!! Scrapmetal Dude !!!! You stopped Waayyyyyyy to soon with the pictures. ! We need to see that whole process, step by step. With NFL instant replays. PLEASE !!

Okay, but if this is deemed to be too "off topic" for the OP I'll pull this post. I'd hate to hijack someone's thread.

I started with a set of 6" x 3" x 1.5" aluminum soft jaws from Monster Jaws, fired up the mill.

http://www.arcaneiron.com/machines/arlowerjig01.JPG

Here is a shot of the completed "first operation". I set the quill stop for the proper depth and then "went to town" on drilling.

http://www.arcaneiron.com/machines/arlowerjig09.JPG

I pulled the lower out and swapped out the jaws to do some other work and here I put the drilled out casting back in the vise and used the DTI to make sure it was true with the mill.
http://www.arcaneiron.com/machines/arlowerjig14.JPG

I installed the pivot pin and touched off of it with the edge finder to set the "0" on my X-axis.
http://www.arcaneiron.com/machines/arlowerjig12.JPG

To set the Y-axis "0" I touched off one side of the casting, set the zero on my DRO, then switched to the other side and used the "1/2" distance function to find the center line.
http://www.arcaneiron.com/machines/arlowerjig13.JPG

Finally, here is a shot just as I'm finishing up the plunge/roughing out.
http://www.arcaneiron.com/machines/arlowerjig15.JPG

Finished with the firing mechanism cavity.
http://www.arcaneiron.com/machines/arlowerjig11.JPG

Switched back to a set of flat jaws and used some spacers to set the lower on it's side, level, and with enough clearance to drill through.
http://www.arcaneiron.com/machines/arlowerjig17.JPG

Installed a 1/8" spotting drill and marked the location.
http://www.arcaneiron.com/machines/arlowerjig20.JPG

Followed that up by drilling a 1/8" hole all the way through both sides of the casting.
http://www.arcaneiron.com/machines/arlowerjig21.JPG

End of part I see next post for part 2.

-Ron

[ScrapMetal]

Continued from part I

To finish out the first hole I used a 5/32" chucking reamer. Back gear and around 80 rpm.
http://www.arcaneiron.com/machines/arlowerjig22.JPG

Now it's on to the hole for the safety selector. Now with a 3/8" spotting drill.
http://www.arcaneiron.com/machines/arlowerjig24.JPG

In the next pic I used a 23/64" drill to make the hole through the casting. I could have maybe used a 3/8" but I don't trust the drills to be accurate and that would have left very little room for error.
http://www.arcaneiron.com/machines/arlowerjig25.JPG

Like the previous holes I chucked up a reamer, 0.376" this time, and put the finishing cut on the hole. Here you can see where I had to slide the aluminum spacer out of the way. Once again, back gear and 80 rpm.
http://www.arcaneiron.com/machines/arlowerjig26.JPG

The "finished" lower (sorry, I didn't take pics of milling out the hole for the trigger.)
http://www.arcaneiron.com/machines/arlowerjig27.JPG

A shot of the test fitting of both the hammer and trigger assemblies. I disassembled it and hit the milled area with Brownell's Aluma-Hyde II paint.
http://www.arcaneiron.com/machines/arlowerjig28.JPG

Finished lower waiting for upper.
http://www.arcaneiron.com/machines/arlowerjig30.JPG

I finished it up with Troy Industries folding battle sights, front and rear (in the lower picture the eyepiece is moved to the side in order to raise the rear sight), an EoTech holographic sight and magnifier, and all Magpul furniture. The Troy battle sight is high enough so that it can be used without removing the EoTech sight though it might not look it from the pictures.
http://www.arcaneiron.com/machines/AR762_02.jpg

Sorry for all the pics/detail but I tried to trim it down to the essentials (I really did!)

Let me know if this was too much,

-Ron

[nun2kute]

Beautiful !!! TY !

[Texas by God]

Actually kind of fun this way.https://uploads.tapatalk-cdn.com/20191026/5ed17ac48c53772076a2f484b3a66fdd.jpg

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[cwtebay]

Actually kind of fun this way.https://uploads.tapatalk-cdn.com/20191026/5ed17ac48c53772076a2f484b3a66fdd.jpg

Sent from my SAMSUNG-SM-G930A using TapatalkOk, that's cheating!!! But in a fabulous way!!

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[BNE]

Ron,

Thank you for the pictures and guide. I had always wondered what was involved.

Texas by God: - What are you showing? We need more details / pictures!

BNE

[Texas by God]

That’s a router for milling out the 15% then the drill press for the last 5%. The jig is the Gen 2 version mentioned in the first post. It works very well. I’ll post some more later.

[ScrapMetal]

That’s a router for milling out the 15% then the drill press for the last 5%. The jig is the Gen 2 version mentioned in the first post. It works very well. I’ll post some more later.

That does look much nicer than the jigs I've seen. I'll be looking forward to seeing your finished lower.

-Ron

[Texas by God]

I need to do a little deburring but overall I think it's ok. A lower parts kit will tell me soon enough.https://uploads.tapatalk-cdn.com/20191026/b8988236672494829e6c97227575095b.jpghttps://uploads.tapatalk-cdn.com/20191026/80ef51e6ef5456da2697b5a79a85e7dc.jpghttps://uploads.tapatalk-cdn.com/20191026/5a685f0e73c6256820485b3702a2349f.jpg

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[cwtebay]

Looks a darn sight better than my first attempt!!!

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[ScrapMetal]

Looks a darn sight better than my first attempt!!!

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I'll second that. Nice job.

-Ron

[Texas by God]

Thanks, guys. This jig set up is almost idiot proof but I'm a veteran decorated idiot so I managed to scare myself a time or two. But it turned out well so on to the black one next. I'll assemble the FDE one first, though to see if everything is everything.

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[lksmith]

Thanks, guys. This jig set up is almost idiot proof but I'm a veteran decorated idiot so I managed to scare myself a time or two. But it turned out well so on to the black one next. I'll assemble the FDE one first, though to see if everything is everything.

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Yeah, first one I did, i went too deep with the router and ruined the lower, but I've successfully done about 5 so far (AR15, AR9, AR10 Aluminum, AR10 Polymer). I actually took advantage of the free lower offer to get the AR9 lower, that is a fun toy for sure! Also, now that I have the lowers, I can piecemeal the parts to build my daughter a hunting rifle by the time she's old enough.
The one thing where I disagree with the instructions on, is once you get to the "3rd cutout" on the jig top plate that acts as a depth gauge, start fitting the trigger. I have found more often than not, if I follow the instructions exactly it isn't deep enough for full movement of the selector.

[lksmith]

I need to do a little deburring but overall I think it's ok. A lower parts kit will tell me soon enough.https://uploads.tapatalk-cdn.com/20191026/b8988236672494829e6c97227575095b.jpghttps://uploads.tapatalk-cdn.com/20191026/80ef51e6ef5456da2697b5a79a85e7dc.jpghttps://uploads.tapatalk-cdn.com/20191026/5a685f0e73c6256820485b3702a2349f.jpg

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I got some sanding "fingers" from harbor freight to use on my oscillating tool to clean up the sidewalls. on my that is the only part that doesn't turn out pretty, although totally functional. just haven't taken the time to try it yet.

[Texas by God]

I only had to scrape the right selector switch hole a titch and it's done. Well, except for sights.https://uploads.tapatalk-cdn.com/20191028/3c315ef865b1aeac6ff0b34d78745481.jpg

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[ScrapMetal]

Nice looking rifle. I have to warn you though, now that you've become an expert at %80 lowers, you'll start thinking things like, "Hmm, I can pick up a .224 Valkyrie upper cheap, and that Beowulf might be kind of fun, and why not a 10mm, and..., and..., etc.

It's a sickness I tell you. :-P

-Ron

[Texas by God]

It's just another symptom of the disease, Ron.[emoji16]

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[Texas by God]

I thought I'd done something wrong because it wasn't working right. 3 in 1 oil bailed me out and it's running fine now.
So I'm starting the black one......https://uploads.tapatalk-cdn.com/20191104/cc10f5c681a3287ce71b19bec669144f.jpg

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[cwtebay]

I find the more I do any sort of metal cutting, the more oil I use. And the more oil I use, the more I appreciate good cutting oil from junk. I used lard on recommendation for aluminum. I built my wife's with some whale oil I had aquired - worked awesome, but not sure that's a super viable option.

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[ScrapMetal]

When cutting aluminum I use WD-40 for cutting fluid. It works very well but be sure you have sufficient ventilation as burning WD-40 probably isn't something you want to breath too much of.

Also, make sure you have good chip removal. I've used a vacuum attachment to pull the chips out of the cut. If you don't clear the chips they will bet pulled into the drill bit/end mill and end up making your cut look rough.

FWIW

-Ron

[Texas by God]

The vacuum attachment works well. I used wd-40 on some cuts and diesel on some cuts and they worked the same.

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[lefty o]

thats definately not terrible for a first try. have seen some that look like they were cut out with a dull chainsaw.

[drac0nic]

My advice having used a couple of the drill press jigs is get a pack of the 1/8 bits and change out your bits fairly constantly. I use the drill press stops in conjunction with the table height to set the depth. It's kind of hard to explain. Also, my next one will probably be done with drill stops as well which I haven't done yet.

As a question I usually go from 1/8 to 3/8 bits with my jig. Does anyone just use a large drill and do the centers only then mill away the rest?

[Texas by God]

You start in the pilot hole and mill in small circles a fraction at a time. The ersatz shop vac connection is nice, huh? It works, though.https://uploads.tapatalk-cdn.com/20191107/dace724d4f47f33428baed34af99ffdb.jpg

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[cheese1566]

I am currently debating the same jig you are using, but also leaning towards the 5d tactical jig.

Did you get the optional side plate for helping to drill the pivot pin holes? Or just drilling through the side plates?

How is the end mill holding up?

[Texas by God]

The pivot / takedown pin holes are factory drilled. I just secure it on its sides to drill the selector, hammer and trigger holes. I've seen a bolt on alignment tool to use if you're using a portable drill. The end mill is still sharp- I'm tempted to go faster but I ask myself why?

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[sundog]

My personal experience is that the 5D Tactical works extremely well.

[Rockzilla]

Have all 3 jigs currently, prefer the Modulus Arms jig it's has some differences vs. the 5D Tac. like a refinement or version 5.2
Use Tap magic for Aluminum, works great. for the vacuum cleaner part, check out HomeDepot or such in the plumbing dept.
find a pvc coupler to fit the jig vacuum port. and those "chips" fly everywhere... you can't just do one..they multiply rather
quickly. Try your hand at some 1911's fun to build, and some of the HK family.

[merlin101]

Thanks Rockzilla! I couldn't remember what the tapping fluid I had out there and just sat down and didn't want to get up to check!
Tap Magic or Tapmatic not sure but a little goes a looong way, I've used it on the lathe foe super fine cuts too.
I have a 5 D jig and like it I've used a few others that where junk (want one?) the only drawback one 5 D is the special router bit, it's $$ I did find a place to get them a bit cheaper I believe it's American gun smithing supply.
Those chip do FLY! The last one I did I used a cheap blue tarp and cut a hole in the center and hung it over my vice, that kept the chips from going all over and when done I just wadded it all up and tossed it.

[Texas by God]

Here's my favorite. Raw lower, CMMG upper, Velocity trigger.https://uploads.tapatalk-cdn.com/20200220/512db0e0a003ef67b4dc7aea33c88f7f.jpg

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[cwtebay]

Well done Texas!!

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