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dpmsman

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Reply with quote  #1 
I'm considering buying a jig and trying an 80% lower for my next build and have a few questions.
1. What is the durability of the hand drilled pin hopes? Meaning will they start to egg over time since they will not be anodized?
2. What is the best jig to go with router or drill press?
3. Is there a used market for the jigs? Meaning were would be a good place to find a used jig? If I can save a few bucks on the jig that's more money for the build right?

Any thoughts or ideas are appreciated. Thanks
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ussrangersm3

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Reply with quote  #2 
Paging Wikster... he's the man that can answer this I'm sure :-)
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Pirate24

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Reply with quote  #3 
1.  Hand drilled holes present no problem for me.  However,  you can eliminate any concerns with a drop-in trigger using anti-walk pins.  Also, to minimize any error, partial drilling into the blank from each side has been recommended by some manufacturers. 

2.  EP Armory has an inexpensive jig they claim will work with either drill or router, although I've not used either their jig or a router.  All of my 80% lowers have been hand drilled for holes then drill press for the pockets.  I believe a router would do a very fine job but I couldn't justify the expense. How many do you plan to make?   I've seen a composite jig once that I wouldn't hesitate to use for an aluminum blank but would still prefer a proper jig.  I've made several poly lowers and most come with their own jig.

3.  Never seen any used jigs for sale and can't remember where I bought mine (maybe off ebay back in the day).   I would imagine that any reputable business selling 80% would serve you well for a jig.  Look for one with replaceable plates if planning on several lowers.


The critical areas to watch when machining are your depths and sides!   My first one was a poly and I blew right through the bottom.   I patched it up with epoxy and a thin piece of aluminum, drilled out the trigger hole, and used a drop-in trigger and still use it with no issues.  Slow going gives the best results. "Measure twice, cut once" to quote a phrase.   I use a small fine flat and half-round file to clean up the pockets, a Dremel would work as well.   A cross-slide vise is handy if using a drill press.
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wikster1983

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Reply with quote  #4 
I agree with Pirate. I have done 8 or 9 80% lowers. I use a EP ARMORY jig, don't buy used as top plate almost always gets slight amount of damage through regular use and the reason they sell replacement plates. Just buy new first and damage it yourself, lol. I have only done one aluminum lower, was pretty easy, but just take it slow. I use a mill at my work, so they turn out pretty nice, when I do my part and slow down. Another easy poly option is the POLYMER 80, has a steel insert for the grip which I like better than taping into the poly like the ep armory ones (and others), they come with a one time use plastic jig that is pretty dummy proof, but they cost three times as much. Ep armory has good deals though, you can get buy 3 get one free for like $100 shipped, where as polymer 80 are like 60-75 shipped depending on sales or where you find it, and aliminum can be as cheap as $30 all the way up to $300 depending on what your needs/wants are! Manventure outpost will do custom engraved lowers in aluminum, they ship pretty quick, are fair priced, and are that little extra touch for your special build! Poly lowers had a bad name many years ago, and I'm sure there are bad ones still out there, but I have not had any problems with mine on my 223, 6x45, 277 wlvs, 300blk, and now my 357ar, going to flip one of my bigger cats (yeti/sabercat) on one to field test, try to break one and report back in summer after round count is there, 1000 seems to be the breaking point supposedly. I have well over that on some of my polys, some have been multiple calibers in multiple different types of setups. Sorry got long winded- just my experience $.02.

Edit: I have only one that has a mil-spec type trigger in it, no egged out holes after thousands of blk rounds, but I do not like mil-spec type triggers. Usually put drop-in single stage triggers in, I would suggest putting in anti-rotation pins in, if your worried about that, but most of mine just have anti-walk pins.

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kdbarker

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Reply with quote  #5 
I'm a big fan of 80% lowers and have done quite a few. I use the Juggernaut Tactical Universal Jig and it has held up great. I will admit I use a vertical mill so the jig does not take much abuse. I use ManVenture Outpost and more recently Tactical Machining for custom engraved 80% lowers.
One of the reasons I build from 80% lowers is NOT cost savings (as some would think) but is the ability to have custom engraving done. This allows you to build a truly custom rifle that is unique to you with your specified identification markings.

Attached Images
jpeg 20171210_101839.jpg (5.29 MB, 18 views)


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ussrangersm3

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Reply with quote  #6 
Quote:
Originally Posted by kdbarker
One of the reasons I build from 80% lowers is NOT cost savings (as some would think) but is the ability to have custom engraving done. This allows you to build a truly custom rifle that is unique to you with your specified identification markings.
that makes sense... I never could understand with the cost of lowers nowadays why somebody would build an 80%

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dpmsman

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Reply with quote  #7 
Thanks for all the great info! KDBARKER those are some great looking lowers! So what is better aluminum or polymer?
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wikster1983

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Reply with quote  #8 
Quote:
Originally Posted by dpmsman
Thanks for all the great info! KDBARKER those are some great looking lowers! So what is better aluminum or polymer?

For what caliber were you thinking? Anything .223 based a polymer would be fine unless you want to abuse your gun harder than a 4x4 post. If wanting to use with a .308 based 'cat, then I would say an aluminum, only because I haven't personally tested it with a polymer .......yet!

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dpmsman

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Reply with quote  #9 
Well I just bought 3 80% billet lowers and a jig from Noreen firearms. They are running a sale $39.99. Forged were $29.99 but were sold out. I figured if I'm going to dive in it might as well be head first! Jig was $65 but no bits or end mills. Just need to figure out what color to cerakote them.
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Moleman

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Reply with quote  #10 
I have done only aluminum ar15's with a Tactical Machining jig and ar10's with a aim small jig.  Now it's cheaper in the long run to go with a FFL lower, but I think they're fun to make and as KDBARKER mentioned you can mark them however you want since you're the manufacturer.  My son picked out a Michigan outline with a deer skull in it for instance.  Coated it in FDE gunkote baked it, then went back over it with HK black to color in the logo and info. I was able to wipe off the overspray with MEK and leave the black in the low spots. Baked it a second time and it turned out great. Did the same thing on my ar10 and my oldest daughters ar15 only with the colors reversed.  Kept the MI deer logo on them for a family deer hunting type thing. 


N15.jpg  357AR.jpg  44BGM-Hybrid.jpg 

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kdbarker

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Reply with quote  #11 
Nice builds there Moleman. Dpmsman, it's a very rewarding experience to make you own lowers from 80%. Once you are comfortable doing it, it opens up some unique options for engraving, customizing, etc... I do have a couple polymer lowers, but for the custom engraving option you will want to buy aluminum.



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battle rattle

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Reply with quote  #12 
i'd be careful using the M word
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dpmsman

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Reply with quote  #13 
Moleman you sure build some awesome rifles! Not sure if you've mentioned this before but are you self-taught or have you gone to school for Gunsmithing?
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Moleman

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Reply with quote  #14 
Thanks DPSMAN, self taught. Was always mechanically inclined and ended up taking machine shop for three years in high school. Didn't touch another lathe for about 20 years when my wife bought me a 9x20 lathe, then a bench mill.  Added two more bigger lathes and a horizontal mill over the years.  It's a hobby for me and luckily things have worked out that I have space for the machines and can work on them when I want to or take a break. 
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kb31416

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Reply with quote  #15 
I checked the Noreen 80% lowers. I have found that it is easier to mount in a jig using the two takedown pin holes if there is a pocket already milled out around the rear pin hole. Most 80% lowers have this design now, the Noreen don’t. As a result, I did not get any.
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Moleman

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Reply with quote  #16 
If the 80% has the pocket already around the rear take down pin, then you don't have to connect the fire control pocket to it.  Less machining.
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dpmsman

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Reply with quote  #17 
I guess that wasn't a real deal-breaker for me. I'm going to be in there Milling anyways so what's a little bit extra. I thought the price was right at $28.99.
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dpmsman

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Reply with quote  #18 
Moleman where do you get your gun kote at? I was looking at cerakote what's the difference between them?
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Bajabusdoc

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Reply with quote  #19 
Mark as always I will support what ever you make sign me up for 1. "Never disappointed. Quality worth paying for"
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Moleman

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Reply with quote  #20 
Quote:
Originally Posted by dpmsman
Moleman where do you get your gun kote at? I was looking at cerakote what's the difference between them?
 

Midway, brownells or straight through KG industries.     http://www.kgcoatings.com/products/firearm-related-products/protective-coatings

Only ever used the airbrush style with a cheap airbrush. Your sort of just mist it on gradually building up a finish on a warm part.  Then bake it at some point as the paint isn't tough at all until it is.  I have some of their air dry that we were going to use on a scope but haven't yet.  Small parts in a toaster oven and bigger stuff in the oven in the house.  Do it when the wife isn't home and air out the house as it gives off a smell while it's baking.  

I've never used cerakote, but it looks good also.  The only thing I have coated with it is my suppressor from the factory and it seems to be holding up fine. 
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