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9/22/2017 12:11:25 AM
Posted: 3/3/2006 10:29:22 PM EDT
[Last Edit: 3/3/2006 11:47:56 PM EDT by Elijah]
Does anyone have pics of 80% lowers?Thanks In Advance
Link Posted: 3/4/2006 4:52:39 AM EDT
[Last Edit: 3/4/2006 4:56:22 AM EDT by die-tryin]

Originally Posted By Elijah:
What work has do be done to complete an 80% lower?



About 20% more. Oh!!!!! I crack myself up sometimes.

Look around here in the build section, there are quit a few topics on this. Some ppl have even used 0% lowers for their builds, etc.
Link Posted: 3/4/2006 5:31:23 AM EDT
It may be more work than you think. Unless you have machine tools.

I also recomend that you get a forged lower and not a cast one. The cast ones actually need LESS machine work to finish, but the quality of the cast lower I got was pretty poor. There was a lot of variations of density to the casting and I am concerned as to its strenght. The forged lowers need more finishing work, but the alloy is very dense and very strong.


This is the forged lower having its buffer tube hole cut and threaded.

I don't have a photo of the cst lower handy, but I may be able to shoot one if you really need it.

efxguy
Link Posted: 3/4/2006 8:15:13 AM EDT
I'm not so sure every 80%er is the same. Most of the work is hole drilling. Oh, and tapping the buffer tube hole. That seems to be where alot of hearache comes from. The chances of hand tapping that hole square are pretty low.
Link Posted: 3/4/2006 9:26:22 AM EDT

Originally Posted By mongo001:
I'm not so sure every 80%er is the same. Most of the work is hole drilling. Oh, and tapping the buffer tube hole. That seems to be where alot of hearache comes from. The chances of hand tapping that hole square are pretty low.



I have access to a mill.Hopefully I can get it square. Other that drilling is there any areas that have to be milled?
Link Posted: 3/4/2006 1:50:17 PM EDT
[Last Edit: 3/4/2006 1:50:56 PM EDT by anotherred]
Kt AR15 A. Drill out the premarked holes, tap the buffer hole that has tap "leads", and file/machine out the ft take down notch. Oh dont forget to look into anodizing DIY or having it done. This reciever almost finished its self for me. http://www.hunt101.com/watermark.php?file=548/32211ar15_034-med.jpg
Link Posted: 3/5/2006 5:13:11 AM EDT
Great info on lower build projects here:

Linky

This applies to a 0% forging, but will cover an 80% lower very very well.

efxguy
Link Posted: 3/5/2006 3:47:13 PM EDT
I have been thinking of trying this method of "build my own".....Has anyone used the CNC jig for this?....and did it work well?
Link Posted: 3/5/2006 10:41:18 PM EDT
ive used the "cnc" jig on a kt15-A and it woked great.

i finished the sucker with a dremel and a drill press. I got the KT15-b now and thats even easier to finish.
Link Posted: 3/5/2006 11:09:07 PM EDT

Originally Posted By sysops666:
ive used the "cnc" jig on a kt15-A and it woked great.

i finished the sucker with a dremel and a drill press. I got the KT15-b now and thats even easier to finish.



How much were was the kt15-a and the kt15-b recievers?
Link Posted: 3/6/2006 10:22:16 AM EDT
Basic Info every 80% builder should have:
Front pivot pin - hole drilled with 1/4"
Rear takedown pin - hole drilled with 1/4"
Trigger pin - hole drilled 5/32
Hammer pin - hole drilled to 5/32
Selector - hole drilled to 3/8
Bolt hold-open plunger drilled with 5/32" to a depth of .470"
Trigger guard - left side - drilled with 1/8" through both ears
Trigger guard - right side - drilled with 1/8" through only one ear
Front pivot pin detent - hole drilled with 3/32" to 1.125" deep
Rear takedown pin detent - hole drilled with 3/32" through to detent pin hole
Selector detent - drilled through to selector with 1/8" then countersunk with 5/32"
Bolt hold-open pin - hole drilled to 3/32" with 6" aircraft bit
Stock index hole - drilled with 1/2"
Grip hole drilled - with 7/32"
Buffer stop plunger - hole drilled with 1/4" to .712" deep
Fire control well milled - by .030 with a 3/8" end mill - optionally shave down your parts to fit the undersized pocket.
Rear takedown well milled - by .030 with a 3/8" end mill - optionally shave down the rear lug of the upper receiver to fit the undersized pocket.
Buffer hole reaMed - to 1 1/8"
Buffer hole tapped to -1 3/16" with 16 tpi
Rear takedown pin relief - cut with a 3/8" end mill
Grip hole tapped - with 1/4" By 28 tpi

This site is very helpful:
concealcarry.org/ar15/bs-home.htm
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