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[ARCHIVED THREAD] - 80% Lower, Drilling Too Deep In Back Pocket

Posted: 11/17/2013 12:09:49 AM EDT

So my drill-press noob self was working on finishing my 80% lower receiver, when I realized that I misread the plans and milled-out too much material (about 1" in depth instead of .630") in the rear-most pocket of the receiver (behind the trigger, by the safety-selector switch hole up to by where the stock attaches). Clearly I screwed it up, but how critical is this? Will the gun still function if I put it together or do I need to restart?

Thanks

Posted: 11/17/2013 12:32:07 AM EDT

[#1]

As long as you have the correct width it should be fine. If you cut to wide you will expose the selector detent hole.

Posted: 11/17/2013 7:57:33 AM EDT

[#2]

Drop some Milliput epoxy putty into the thing. Practice a bit before putting it into your lower. Use water to keep your fingers wet and tamp the putty down with the flat end of a tool like a punch.

Posted: 11/17/2013 1:14:34 PM EDT

[#3]

look at the blueprints for a M-16, that area's milled out anyway to accomodate the auto sear.
don't worry, if you can't see daylight through it, it's ok.(just watch out laterally like's been posted that selector detent hole is close)
and don't worry about it (maybe,probably not) being able to accept a auto sear, as long as the auto sear holes aren't drilled you're ok there,too.
there's no law that says we have to do a lower any one way.

but you certainly COULD fill the void with epoxy and remachine if you wish.
there's a epoxy putty available at auto part stores that you cut off a section (iboth halves are in a tube) and knead it till uniform then push into place.
i've actually tapped it once cured and it holds for light duty.

it's all up to you.

Posted: 11/17/2013 3:05:47 PM EDT

[#4]

1" deep at the rear take down pocket is pretty damn deep, that's gotta be close to poking out of the back strap radius.

Posted: 11/17/2013 4:43:15 PM EDT

[#5]

if thats the area (commonly called the shelf, as in low shelf vs, high shelf) then its ok as long as its not all the way through.
close and thin don't count, can't put it back anyway.

Posted: 11/17/2013 5:33:56 PM EDT

[#6]

Thanks everyone, glad to have the help and thanks for the idea with the putty!

Posted: 11/17/2013 7:15:39 PM EDT

[#7]

Quote History

Quoted:
As long as you have the correct width it should be fine. If you cut to wide you will expose the selector detent hole.

View Quote

I did this tonight and exposed about 1/3 of the selector detent hole before I knew it.

Is this lower trash now?

Posted: 11/17/2013 9:20:31 PM EDT

[#8]

Quote History

Quoted:
1" deep at the rear take down pocket is pretty damn deep, that's gotta be close to poking out of the back strap radius.

http://global.fncstatic.com/static/managed/img/Scitech/3d%20printable%20gun.jpg

View Quote

While the original AR-15 print does call for a .630" depth, IMHO it is way to deep and unnecessary from a Engineering perspective...I would
submit that a .525" depth for the rear shelf take-down pocket is more than sufficient (just like in the AR-10B original prints)...It will give you
a stronger lower and will require less machining time for your 80% builds.

Also, please read your prints carefully before attempting to start your 80% AR-15 builds, you don't want to wind up with a expensive paperweight.

There are plenty of good Engineers/Machinist's/Builders on this board that can help some of the new builders out there on this forum...

Good Luck.

Posted: 11/18/2013 7:56:37 AM EDT

[#9]

Quote History

Quoted:

I did this tonight and exposed about 1/3 of the selector detent hole before I knew it.

Is this lower trash now?

View Quote

No...
Just like above. use some Epoxy putty, or my favorite J-B Weld.
Fill in - Build up the affect area. Let Epoxy fully setup overnight!!
Now just finish mill the area as needed.
The Re-Drill the detent pin/spring channel..

Good Luck

Posted: 11/18/2013 9:47:33 AM EDT

[#10]

Quote History

Quoted:

No...
Just like above. use some Epoxy putty, or my favorite J-B Weld.
Fill in - Build up the affect area. Let Epoxy fully setup overnight!!
Now just finish mill the area as needed.
The Re-Drill the detent pin/spring channel..

Good Luck

View Quote View All Quotes

View All Quotes

Quote History

Quoted:

Quoted:

I did this tonight and exposed about 1/3 of the selector detent hole before I knew it.

Is this lower trash now?

No...
Just like above. use some Epoxy putty, or my favorite J-B Weld.
Fill in - Build up the affect area. Let Epoxy fully setup overnight!!
Now just finish mill the area as needed.
The Re-Drill the detent pin/spring channel..

Good Luck

I will try that out.

This was my first try and milling so I am not to mad.

Posted: 11/18/2013 6:23:48 PM EDT

[#11]

You are not the first guy to over-mill that area, or to mill the shelf too deep. Luckily it isn't taking much stress there, so the epoxy will be fine.

Posted: 11/22/2013 3:40:07 AM EDT

[#12]

.630 is the Low Shelf measurement if you desire to go to a legal DIAS.

Posted: 11/22/2013 4:14:12 AM EDT

[#13]

Quote History

Quoted:
.630 is the Low Shelf measurement if you desire to go to a legal DIAS.

View Quote

Correct, for which 99% of user will never use...and it can always be re-milled if they change their mind as well...

Posted: 11/22/2013 5:01:15 AM EDT

[#14]

Please see response with quote

Posted: 11/22/2013 5:11:30 AM EDT

[#15]

Quote History

Quoted:

I did this tonight and exposed about 1/3 of the selector detent hole before I knew it.

Is this lower trash now?

View Quote View All Quotes

View All Quotes

Quote History

Quoted:

Quoted:
As long as you have the correct width it should be fine. If you cut to wide you will expose the selector detent hole.

I did this tonight and exposed about 1/3 of the selector detent hole before I knew it.

Is this lower trash now?

I did this and simpliy used a hardened steel dowel to make a longer detent pin and cut the spring length to compentsate

[ARCHIVED THREAD] - 80% Lower, Drilling Too Deep In Back Pocket

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