I've finished a few 80% AR-15 receivers using the original Modulus Arms jig many years ago and they turned out OK.  Functional, but rough if you really looked at them.  Some of that was the early jig that was not the best (at the time it was), but most of it was my learning curve.  First one was bad, second one was better and third one was pretty good.  I also completely underestimated all the aluminum that would be - literally - all over my workbench, the floor, me and everywhere near.  Not easy to clean up, either.

Fast forward and I picked up a new 5D Pro jig for AR-15's and a decided to try my hand at six more 80% receivers.  These ones would be special ones for my kids based on the engravings and SN I put on them, so I wanted to do them really well.  I also wanted to avoid the huge mess that 6 lowers would create.  

I use a DWP611 router, so I got the part that attaches to it and allows a vacuum to connect.  That worked so-so.  Most of the chips come out the bottom of the router where the cutting is being done.  In the end, it mostly served to keep the vacuum within hands-reach to make cleaning out the chips in the receiver faster.  For $10, it was worth it even though it didn't help much.

I put the receiver in the jig.  I used an Irwin vise to hold the jig/receiver and used c-clamps to attach to my workbench.    I used a cut up plastic freezer bag, tucked it under the vise and taped it to the sides of the jig to prevent the shards from flying out the back and sides.  This helped cut down on the vast majority of the debris.  Then, since the mill throws aluminum 360 degrees, I opened both ends of an Amazon box and put it around the vise.  I put the rest of the plastic freezer bag on the top of the box and used some tape to hold it there.  I took one more box, poked some holes in it and used the c-clamp handles to hold the box under the edge of the workbench to catch chips that would make it out and fall into this box instead of onto the floor.  I also put a cardboard barrier around the back - but wasn't really needed.  It helped, but not super-necessary.

I had to lift up the box around the jig any time I wanted to measure the end mill length using the jig template - which wasn't an issue.  After 6 lowers (appx 60-90 mins per lower over 2 days), I had almost zero aluminum chips on the floor and very little on the workbench beyond the cardboard I had set up.  Worked well even though it looked like garbage - lol.

The end result of the lowers in the white was pretty good - considerably better (and easier and faster) than with the original Modulus Arms jig.  I test fit all the lowers with trigger pins and safety selectors and all fit perfectly.  The trigger pin holes I did on each side (not straight through), but if I did the safety selector that way, it was not a perfect test fit of the safety, so I did those on both sides and then did a "straight through" as a cleanup and it worked well.

Just shipped off all six lowers to be anodized today (military hard coat type 3).  Hope they turn out well!

Thats actually a great idea to cut down on the clean up

It really did work well.  I am almost embarrassed to post it because of how crappy the setup looks, but my field-expedient method did work in virtually eliminating the mess outside of the boxed area, so hopefully it will help someone else.  

That's a lot of effort to avoid using a broom...  Good on you, I guess...

lol.  I'm guessing you haven't done an 80% receiver using a router and a jig.  The cleanup for just one lower (much less six lowers) is more than just "a broom" or a vacuum.  Those aluminum slivers get EVERYWHERE, stick on everything and they hurt.  It's like having a ton of metal splinters being thrown in a 5 foot radius in every direction, including up and down.  For 10 mins of metal energy and cutting up old boxes and a bag, it was well worth the effort.

Excellent idea, OP.  I am going to do the same set up when I do mine.

Haha, it does make a hell of a mess, doesn't it? Roughly 87 million WD-40 soaked sharp aluminum chips.

Great idea!

After the first one I did the rest in the back yard on top of a tarp.

I work at a machine shop, we mill hundreds of pounds of aluminum. Crap gets everywhere.

OP has now officially machined more lowers than SOLGW!

Making a ghetto cardboard "blasting box" is a good way to go.  Looks/sounds silly but honestly once you realize the mess that these things make when getting milled you'll understand why.  Shopvac cleanup is significantly easier this way.

If it looks silly/stupid, but works, guess what it ain’t?


Nice setup, OP

Bravo Zulu.

Now melt down your chips and pour a 0% OP.  Make the liberals really cry.

Eh, you need more tools if you have time to clean up after doing every single project.  I vacuum off the mills, and usually keep the bed clean on the lathes, but the chip trays, nooks and crannies only get cleaned a few times a year.  Half of my hobby type milling projects the chips weigh more than the finished project.

But yeah, they get everywhere for sure.  Be happy aluminum isn't sharp.  Mild steel is terrible, stainless is awful.  They slice you or stick in you.  At least if you can't dig them out, the carbon steel will rust away eventually.   Stainless really gets under your skin.

I wish I had the luxury of leaving a partial mess - but my work area consists of a small 4' spot in an enclosed three car garage that has three cars in it (along with bikes, freezer and other accoutrements that a large-ish family keeps in a garage), so I need to keep it clean and walk-way friendly for my kids and wife.  If this were in the corner of my garage or a dedicated workshop, that'd be another story.

Let's play Find the Aluminum Chips, kids!  Take off yer shoes.  

Whats the legality /cost of having you do a couple 80% lowers for me?  I can ship the blanks.

You gonna pay for his 07 FFL and insurance as well?

He can't make it for you. He could make one and sell it Face to face needs to be same state residence

Just curious but does lube really help with the milling? It seems like you would just be milling dry metal after the first circle cut when the lubed surface was removed.

We CNC it dry with air blow to clear chips.

You've got a driveway....got a leaf blower?

Your suggestion is to not only litter but to blow aluminum shards all over the street and others' yards?  

Forbidden ice cream sprinkles

You assume I'd blow it into the street or other people's yards....Interesting. I bag my grass clippings and don't make a habit of running around in my yard barefoot. After a few mows I don't have any significant number of shavings in the lawn

Finally, someone that blows into the proverbial Kleenex instead of everywhere else!

Most of us seek DIY suggestions, and this one appears to work.

LOL I just went to letting them hit the shop floor then sweeping them up.   I tried a couple vacs etc and at the end of the day the broom was easier to deal with.  It wouldnt work that well on your workbench though.  


Also, Where for the HC3 anodizing?

Who did you send it to for plating?

OP can't even make one w/ the intent of selling it.

Vegas Metal Finishing.  It's a subsidiary of New Frontier Armory.  Very reasonable cost if you have multiple.  Not the best if you're only doing one since the process they use is the same if you're doing one lower or six lowers.

How does that old saying go? "If it's stupid, but it works, it's not stupid."

Clever use of materials at hand to solve a problem!

"Intent" it's like the mind police. I can't form one a can with the intent of using a flashlight because the intent already made it a suppressor part.

Whoa whoa hold on there.... You're the man of the house? The garage is your cave brother. Carve out some space for yourself. It's good for you.

Remember, we're in a tech forum, not GD.

My garage is what it is - which is not a workshop - nor do I have any desire for it to be a full-on workshop.  It's rare for me to use my non-airconditioned, enclosed garage in AZ for anything other than storing mechanical things and occasional small tasks.

I also used an Amazon box on my last one, but only three sides to keep them off the bench. All the chips came toward me and I vacuumed them up at the end.

My intent is to force them to try to ban Legos.

I have always used oil when drilling and milling 80% lowers.  It is still messy, but chips do not fly around.

I went a different route.

Got one of these tote bins from HD, cut a piece of 3/4 plywood oversized for the base, and mounted a drill press vice in the center to hold the jig.  Use some C Clamps on the plywood to lock the assembly to whatever work surface I'm using.

I hook the shop vac hose to the jig coupling for the buffer tube, and most of the excess chips remain in the bin for the shop vac.  

Bonus feature; when I'm done, all the tools and parts I need for milling fit inside the bin, so I don't need to scramble to find tools the next time I want to mill.

Yep; cool rig -  you did a much more formal process for essentially the same thing.  I thought about doing something similar, and even thought about designing and fabricating something formally to do this and selling it - but clearly those who feel that the mess is bad enough to merit something like this already do something about it - but most are just fine with a cursory clean-up after doing the work.

I opted for just the temporary, inexpensive box and bag setup because milling out 80% uppers is something I'll probably only do once or twice every 10 years based on my history with it.

I do a cardboard box to enclose back and sides of jig while mounted in my bench vise.

Not perfect but it helps keep chips off rest of bench.  Don't mind some on the floor where it's an easy clean up.

Looks good OP

I wonder how many you'd need to mill to get another lower forged from the chips?

Got notice from Vegas Metal Finishing that the lowers were done, and I paid the invoice today (just under $270 total for all six), so hopefully they should ship back to me tomorrow and hopefully will have them early next week.

I'm super curious and anxious to see how they look after professional hardcoat type 3 anodizing has been done on them!

Especially curious to see how the insides look and if the anodizing affects the lower parts fitment at all (it shouldn't).

Got my receivers back and WOW!  Vegas Metal Refinishing did a superb job on these - they look like OEM receivers.  I was curious if I'd see the light tooling marks from my milling job, but nope - they are perfectly flat and smooth everywhere due to the process.

The only thing I didn't take into account was that the Type 3 Hard Coat Anodizing process adds enough thickness that the formerly easy fitting (not snug) trigger pins and safety selector were super tight.  In the end, I just used a Geissele trigger pin tool to push into the pin holes and lightly spin it and wiggle it up and down (barely).  That was enough for the trigger pins.

On the safety, I had to use a file - only a few light passes - not even enough to remove the finish from inside the hole - and then the safety fit well and would move normally.

Nice!

Awesome, thanks for sharing the pics

Tell me about the router setup deal.
I don’t really follow any 80% builds and just kinda decided to click this while I’m in a waiting room.
I have a small Makita already as well as a drill press.

You'll have to look up your specific router against the different 80% jigs.  

Here's a list of the routers compatible with 5D, but I don't think the list has been updated in a while.  The Makita RT0701C is on the list.

Thanks for the link