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Page AK-47 » Build It Yourself
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Posted: 4/12/2006 9:53:43 AM EDT
A friend of mine has a complete, serialized receiver that he wants to sell (thru an FFL) to me for a Polish UF build.  My question is, how difficult would it be to modify the receiver to work with an UF? Would it involve enlarging any existing holes that would have to be drilled off-center for the rear trunion?

thanks hug.gif
Link Posted: 4/12/2006 10:23:15 AM EDT
[#1]
What is the "regular" receiver built for?  If it's a Yugo UF receiver, no, it would take lots of work.  Probably wouldn't be worth it.  If it's a plain jane NDS-3 or something like that with fixed stock rear trunion holes, you will need to weld in the holes and drill new holes for the UF.  Here's a link to my Yugo UF build on a Tapco fixed stock rear trunion flat build: ak47.net/forums/topic.html?b=4&f=51&t=84665
Link Posted: 4/12/2006 10:25:56 AM EDT
[#2]
Well, depends on your skill level.  TIG over the old rear trunnion holes and grind the welds smooth inside and out.  Go to http//www.ar15.com/content/page.html?id=92 for the proper placement of holes for trunnion and UF stock hardware.  Use drill press with metric bits.  Clean up any burrs.  Test fit UF stock.  Once everything fits well, take it apart, bead blast and blue/parkerize.  Or go the cheap route and paint it.
Viel Gluck!
Link Posted: 4/12/2006 10:34:10 AM EDT
[#3]
Thanks guys - that's just the info I was looking for.  It's a receiver for a fixed stock AK, and since I don't have a TIG I think I'll just go for an 80% receiver.
Link Posted: 4/12/2006 2:19:53 PM EDT
[#4]
Are you guys sure? I thought the rivet holes for a standard stock were correct for an underfolding stock, it just need the 3rd rivet hole, and the holes for the stock itself.

Im pretty sure thats how it is, because some guys are modifying their tapco flats to use and underfolder and are simply drilling more holes, no welding and grinding.
Link Posted: 4/12/2006 3:36:29 PM EDT
[#5]
I have a Polish UF kit and recently purchased an NDS-3 from Nodak.  The front trunion holes line up perfect, on the rear trunion, the rearmost hole lines up well.  The second is off by about the diameter of the rivets themselves, and there is no third hole for the rear trunion.

You could use two holes to mount the trunion to the receiver, cut the extra holes for the UF.  But if you live in a free state, the 80% option is probably better.
Link Posted: 4/12/2006 5:11:47 PM EDT
[#6]
The holes in a fixed stock receiver were "close" for my Polish build.  I used one of my bent Tapcos and the upper rearmost hole worked fine, but the one down and forward of that one had to be "egged" a little.  Other than that I just put the rear trunnion in and held it with screws and slowly hogged the rest of the necessary holes out with a dremel.

Link Posted: 4/12/2006 5:13:57 PM EDT
[#7]
I built a Polish folder on a standard receiver. It will work just fine. The forward rear hole will not be used and will be covered up by the folder. No need to weld it up unless it just bugs you being there. You'll just have a bunch of holes to drill. 4 rivet holes, 4 locking lug holes  and the 2 big holes for the main support sleeve.
Link Posted: 4/12/2006 7:38:59 PM EDT
[#8]
+1 what joebud said!!
Link Posted: 4/14/2006 10:04:13 AM EDT
[#9]

Quoted:
The holes in a fixed stock receiver were "close" for my Polish build.  I used one of my bent Tapcos and the upper rearmost hole worked fine, but the one down and forward of that one had to be "egged" a little.  Other than that I just put the rear trunnion in and held it with screws and slowly hogged the rest of the necessary holes out with a dremel.




Nice idea, I think I will borrow this for tonight.  I was close to using a big drill bit last night to cut the holes, good thing I decided to sleep on it.
Thank you
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