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Thread: 80% Build - Old School style

  1. #1
    Gunco Regular Rocster's Avatar
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    Default 80% Build - Old School style

    So...after having it sit for a few years in the shipping box, I got it out a month or so ago and determined to get it built. _It_ was an old-school style cast 80% AR lower - the kind with the fully finished mag well and trigger area.

    I just had to locate the special tools needed to do the tricky areas..the buffer tube hole ala the big F&*# Drill (BFD) and the big 1 3/16- 16tpi tap. These days those tools are a bit more rare as all the current 80% lowers now have those features completed for you. After months of trying to locate these tools on eBay I was ready to give up and buy them full price somewhere. But with a little help from the Gunco community I was able to get a loaner set of goodies to complete the build. Heck yeah, and a big thanks to everyone involved.

    Guidance and reference for the build steps and setup tips came from:
    CNCGUNSMITHING - www.cncguns.com - AR15 80% Lower Receiver Tutorial
    And the excellent Ray-Vin "Machining the AR-15" free ebook.
    Ray-Vin Technical Pages

    On to the build...
    First up was opening up the buffer tube hole to 1 1/8". I was advised to use a step drill first before the BFD to make it go smoother, and not bind.


    No pics of the actual BFD, but prepping with the Uni drill first helped a bunch! The next pic shops my 'unique' bubba style clamping jig. Its some pine molding I had, and was soft enough to not mar the lower. (And cheaper than those fancy drilling jigs)


    Next was tapping...using a punch in the chuck it setup nicely, and went thru fast.


    After that I tilted the table, and drilled the pistol grip hole (I luv my old Shopsmith). With that done I could then tap that too.


    Now the bolt release hole is pretty tricky, luckily the Ray-Vin book shows you how to make a tiny drill jig out of a small piece of bar stock. I made one and then clamped it to lower with a Quik-clamp as shown, then drilled thru with a long aircraft drill.


    I did some of the other misc. holes, and then it was time for the holy trinity...Hammer hole/trigger hole/safety selector hole. Doing these just by measurement seemed a bit scary, so I opted to be cheap & resourceful by making my own jig from the PDF DIY template I found that was posted at the WeaponsGuild site. I printed it out and then transferred the pattern to a piece of scrap aluminum I had in the workshop. I drilled the holes and it looked pretty good...
    I clamped it up to the receiver left side using the top edge and left casting ridge as my reference points. Drilled the saftey selector hole first , then clamped with a bolt carefully before moving on to the trigger and hammer holes.






    After a few more misc steps it was ready for marking. I opted to use electro-etching as I built my own etching machine. I have been having problems using the photo stencils, so I decided to give it a try using the vinyl decal stencil and Q-tip method. (There is a great detailed thread on this at CalGuns by VaderSpade). I was able to get a great custom stencil made up by Tom L. in Az. at a very reasonable $10. He is more than willing to make them for other folks...PM me for his email contact info if you are interested)
    Here is the finished etching.


    I am setting this up with a AR 7.62x25 custom upper from Prexis, hope to have a final assembled pic up shortly.

  2. #2
    No Hope For Me Coils's Avatar
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    Thanks for the pics and info, I'll try to watch your progress
    "Government is not the solution to our problem, government is the problem" Ronald Reagan

  3. #3
    Gunco Member HHollow's Avatar
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    You should have milled the top plane first. Now I believe your bolt stop hole is going to be high.

  4. #4
    Gunco Regular earnie's Avatar
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    Quote Originally Posted by Rocster View Post
    So...after having it sit for a few years in the shipping box, I got it out a month or so ago and determined to get it built. _It_ was an old-school style cast 80% AR lower - the kind with the fully finished mag well and trigger area.

    I just had to locate the special tools needed to do the tricky areas..the buffer tube hole ala the big F&*# Drill (BFD) and the big 1 3/16- 16tpi tap. These days those tools are a bit more rare as all the current 80% lowers now have those features completed for you. After months of trying to locate these tools on eBay I was ready to give up and buy them full price somewhere. But with a little help from the Gunco community I was able to get a loaner set of goodies to complete the build. Heck yeah, and a big thanks to everyone involved.

    Guidance and reference for the build steps and setup tips came from:
    CNCGUNSMITHING - www.cncguns.com - AR15 80% Lower Receiver Tutorial
    And the excellent Ray-Vin "Machining the AR-15" free ebook.
    Ray-Vin Technical Pages

    On to the build...
    First up was opening up the buffer tube hole to 1 1/8". I was advised to use a step drill first before the BFD to make it go smoother, and not bind.


    No pics of the actual BFD, but prepping with the Uni drill first helped a bunch! The next pic shops my 'unique' bubba style clamping jig. Its some pine molding I had, and was soft enough to not mar the lower. (And cheaper than those fancy drilling jigs)


    Next was tapping...using a punch in the chuck it setup nicely, and went thru fast.


    After that I tilted the table, and drilled the pistol grip hole (I luv my old Shopsmith). With that done I could then tap that too.


    Now the bolt release hole is pretty tricky, luckily the Ray-Vin book shows you how to make a tiny drill jig out of a small piece of bar stock. I made one and then clamped it to lower with a Quik-clamp as shown, then drilled thru with a long aircraft drill.


    I did some of the other misc. holes, and then it was time for the holy trinity...Hammer hole/trigger hole/safety selector hole. Doing these just by measurement seemed a bit scary, so I opted to be cheap & resourceful by making my own jig from the PDF DIY template I found that was posted at the WeaponsGuild site. I printed it out and then transferred the pattern to a piece of scrap aluminum I had in the workshop. I drilled the holes and it looked pretty good...
    I clamped it up to the receiver left side using the top edge and left casting ridge as my reference points. Drilled the saftey selector hole first , then clamped with a bolt carefully before moving on to the trigger and hammer holes.






    After a few more misc steps it was ready for marking. I opted to use electro-etching as I built my own etching machine. I have been having problems using the photo stencils, so I decided to give it a try using the vinyl decal stencil and Q-tip method. (There is a great detailed thread on this at CalGuns by VaderSpade). I was able to get a great custom stencil made up by Tom L. in Az. at a very reasonable $10. He is more than willing to make them for other folks...PM me for his email contact info if you are interested)
    Here is the finished etching.


    I am setting this up with a AR 7.62x25 custom upper from Prexis, hope to have a final assembled pic up shortly.
    i am sending a pm in regards to the etchings, this lower looks great

  5. #5
    GuncoHolic Sprat's Avatar
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    PM sent on the vinyl transfer info

    sprat
    Sprat and sprat1 are one and the same.

  6. #6
    Gunco Regular Rocster's Avatar
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    PMs replied to.

    ALSO:
    Here are links to the 'Vaderspade' etching tutorials:

    Etching HOW TO #1:
    Electro Etching an AR-15 80% lower. - Calguns.net

    HOW TO #2
    Vader Spade’s 80% AR-15 build - Milling, Etching, & Anodizing - Calguns.net

  7. #7
    Gunco Regular earnie's Avatar
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    here is my 80% lower in work
    i am hoping to do a hydramatic m16a1 clone on this and think the markings will make it really stand out

    http://www.gunco.net/forums/f255/buf...uestion-64186/
    here is another link

    http://www.gunco.net/forums/f255/ar-15-80-build-63636/

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