Building an AR from an 80% Lower with Crap Tools

I didn't use mine, just the heavy backer plates so I didn't have a problem.

I messed up the brass barrel pin when my barrel bound up and went in crooked. Twice:/
 
I had a free evening last night, so I decided to give it another try. I've got a few more 80% lowers that I will eventually finish the right way, but I wanted to apply some lessons-learned from the first one and see if I could do better.

This one is an Ares lower, which had the rear takedown pocket already milled. I used the same setup as before, but I used an end mill with shorter flutes, so they didn't hit the jig. I did use a new top plate for the jig, to replace the one that was buggered.



 
mclina said:
I had a free evening last night, so I decided to give it another try. I've got a few more 80% lowers that I will eventually finish the right way, but I wanted to apply some lessons-learned from the first one and see if I could do better.

This one is an Ares lower, which had the rear takedown pocket already milled. I used the same setup as before, but I used an end mill with shorter flutes, so they didn't hit the jig. I did use a new top plate for the jig, to replace the one that was buggered.



Click to expand...

You say you used a jig??

Then how is the pocket so wide???
 
Took both of these to the range today and they worked perfectly with a couple of different uppers.

The first one has the anti-rotation pins from one of my CMC triggers with a standard FCG, and the second one has one of my CMC triggers with the provided pins (changed after the photos). I think these definitely help in forgiving the screwups in the pocket. Everything sits nice and tight, and works great.

I think the only other fear is that I weakened the lowers by taking off too much material, but they seem to be strong enough where it matters. I fired about 100 rounds through each, and then checked very carefully for cracks and didn't find anything. I will definitely keep my eye on them.

Suck it, Kevin de Leon.
 
And here is attempt number 3. I'm pretty happy with this one. It doesn't have the mirror finish inside that you would get from a proper mill job, but all of the dimensions are good, there are no thin spots, and the parts fit and work just fine. This one took me maybe 2 hours.







 
Getting better!

We have toyed with the idea of milling the takedown lug clearance in our 80%s. It does take a lot of the precision requirement out during the process. The problem is that the ATF is VERY critical of the amount of material removed in this location.

As for those of you speaking of a tool rental... We have also toyed with the idea of offering a tool/jig rental program. We would of course manufacture a jig capable of loaner duty...
 
Other Mfg's do it so I quess its ok with the ATF....

TR Enabling said:
Getting better!

We have toyed with the idea of milling the takedown lug clearance in our 80%s. It does take a lot of the precision requirement out during the process. The problem is that the ATF is VERY critical of the amount of material removed in this location.

As for those of you speaking of a tool rental... We have also toyed with the idea of offering a tool/jig rental program. We would of course manufacture a jig capable of loaner duty...
Click to expand...
 
slugworth said:
Other Mfg's do it so I quess its ok with the ATF....
Click to expand...

By that logic:

We should make a polymer lower with an opposite color polymer pocket to be removed...haha

But seriously,

We are fully tracking on the legality of the lug recess, What I am saying is that they are critical to the thousandth of an inch in regard to the forward progression of that lug recess.

Regardless, we will most likely begin production of our 80% units with this recess in the near future.

Not trying to threadjack...
 
Since TR Enabling has chimed in - I want to give them a thumbs up. I ordered a replacement top plate for my jig, at what I thought was a fair price, and they sent me two. And they shipped them super fast.

Now that I have my process down, I think my jig will last for twenty more lowers. Not that I plan on finishing that many. My house is already feeling haunted.
 
inerlogic said:
i won't post photos of the hack job i did on a 10/22 80% receiver...... oy vey.......
Click to expand...

Should I post some of my 0% (or is it 100%) 10/22 receiver? I printed it in my living room.

Now I am looking to see what it would cost to have an 80% equivalent cast in brass from my 3D printed patern (missing all the holes of course).
I have a feeling it is going to be cheaper to just buy the billet (~$70 for one receiver).

I should probably go start another thread for the 10/22 receivers...
 
TR Enabling said:
As for those of you speaking of a tool rental... We have also toyed with the idea of offering a tool/jig rental program. We would of course manufacture a jig capable of loaner duty...
Click to expand...

Tool hardened stainless? I can't imagine a jig capable of loaner duty!
 
massBRS said:
Tool hardened stainless? I can't imagine a jig capable of loaner duty!
Click to expand...

if there is one thing to be said about loaner tools [rofl] no steel is stronger than stupidity (or ignorance)

There are several 10/22 80% available. Some come with top tails milled. If you wanted to know, Ruger's 10/22 receiver is cast.

Also, I saw another site adverting router jig for lower making. I think that popularity for those is on the upswing.
 
I have a lower to finish, but I can't decide if I should jig it or do it manually.

I have a small mill, so I am not talking about eyeballing it with a marker and a drillpress.

I figured out a way to accurately locate the trigger and safety holes based on the locations of the already machined take down pins. I calculated the radial distance for each hole from each pin. A 0.25 inch pin with a center divot and a pair of dividers will let me mark an arc from each pin. Where they cross is where the hole goes. My trial runs at marking the lower look really good.

My real problem is holding the lower to mill the pocket.

It looks like I need a jig of some sort anyway just to be able to grab the thing.

The only think that looks promising is clamping the already machined grip area. My concern is that this puts the cut mighty far from the vise. Anyone done it this way before? Am I nuts? Should I just get a jig?

Also, is it a good idea to have the lower parts kit on hand while completing the lower, or does it not matter?
 
JackOfAllTrades said:
I have a lower to finish, but I can't decide if I should jig it or do it manually.

I have a small mill, so I am not talking about eyeballing it with a marker and a drillpress.

I figured out a way to accurately locate the trigger and safety holes based on the locations of the already machined take down pins. I calculated the radial distance for each hole from each pin. A 0.25 inch pin with a center divot and a pair of dividers will let me mark an arc from each pin. Where they cross is where the hole goes. My trial runs at marking the lower look really good.

My real problem is holding the lower to mill the pocket.

It looks like I need a jig of some sort anyway just to be able to grab the thing.

The only think that looks promising is clamping the already machined grip area. My concern is that this puts the cut mighty far from the vise. Anyone done it this way before? Am I nuts? Should I just get a jig?

Also, is it a good idea to have the lower parts kit on hand while completing the lower, or does it not matter?
Click to expand...
Getting a jig will make your life a lot easier. It can definitely be done without one, but they're relatively short money and last a long time if you're not chopping into them with the bits, so why not?

I think that it's already been mentioned in this thread, but if you decide to get a jig, get the one from aimsmall. It's really nice and high quality.

Having an LPK around when completing an 80% lower helps a lot for double checking that everything is done like it should be.
 
there is that famous PDF (ARblank.pdf) about making a lower from 0% casting. The lower has to be held down with some really odd-ball setups to square away surfaces etc. but not of them is an actual jig. It's doable but take your time and make sure that you secure the piece well. The pdf can give you some ideas how to hold down the part.
 
Golddiggie and Dave coached me. And mine came out perfect [smile] Got me into actually machining things and now I work for a MIL-I-45208A Registered machine shop (Soon to be ISO 9001 under my supervision). But all in all I think some people never even touched a screwdriver that showed up to that party [rofl]
 
Last edited:
dyer01905 said:
Golddiggie and Dave coached me. And mine came out perfect [smile] Got me into actually machining things and now I work for a MIL-I-45208A Registered machine shop (Soon to be ISO 9001 under my supervision). But all in all I think some people never even touched a screwdriver that showed up to that party [rofl]
Click to expand...

I have been present for at least fifty 80% AR lower machining jobs. We did have some teething pains starting up,
but the finished milling procedure has been well simplified with minimal tool changes. My last Billet AR lower was
machined in just under 1 hour and within 24 hours of receiving the package.

Malodave
 
Boris said:
there is that famous PDF (ARblank.pdf) about making a lower from 0% casting. The lower has to be held down with some really odd-ball setups to square away surfaces etc. but not of them is an actual jig. It's doable but take your time and make sure that you secure the piece well. The pdf can give you some ideas how to hold down the part.
Click to expand...

For 80%
I just made taller soft jaws and made some spacer stock for a friend. Have the jaws wider then the take down pins. Mill the top of the jaws. Sticks pins in the take down holes. then rest them on top of the jaws. Now you know the lower is sq to the spindle . A jig is nice if you don't have dro's/ dial type device(I forget what it's called) think analog dro's.... Or really shitty back lash.
 
71montess said:
Any thoughts on this tool used with a drill press. Dont know about its quality.http://m.ebay.com/itm/231531175589
Click to expand...
It's usually called a milling vice. The problem with using one of those with a drill press is that actually milling with the drill press puts sideways pressure on the chuck, which drill presses aren't designed for. Your chuck will keep dropping out. Better off saving your nickels and dimes and getting a real mill.
 
knfmn said:
It's usually called a milling vice. The problem with using one of those with a drill press is that actually milling with the drill press puts sideways pressure on the chuck, which drill presses aren't designed for. Your chuck will keep dropping out. Better off saving your nickels and dimes and getting a real mill.
Click to expand...

Plus it looks frickin tiny... [shocked] [laugh]
 

Similar threads

Modifying preban uzi mags for AR9 colt lower
Replies
15
Views
147
Marty McFly
Marty McFly
How to Remove an Older Handguard
Replies
10
Views
346
mac1911
M
Muzzle-loading cannon (from extruded brass stock)
Replies
11
Views
217
MisterHappy
MisterHappy
Colt vs. Glock AR-9
Replies
4
Views
179
jayhitek
jayhitek
Anyone know a skilled woodworker in Boston Metrowest area?
Replies
0
Views
97
hminsky
H
Back
Top Bottom