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Posted: 4/7/2016 9:38:59 PM EDT
| I'm building my first AR and I ended up getting a MOE lower parts kit. The grip screw was a good bit wider, it seems, then the others I've had. I even had a Stag one to compare after I marred up the threads good with this thing and it seems a good bit narrower? I am looking for anyone who could possibly help me tap or sink these threads out, maybe a machinist who's some experience with a helicoil if I need it. It's only the first four or three rows of thread but now after I had the bright idea to take the damn grip off and try to just screw into the block, it will not thread past the point that is bugled. I can't recall the term for backing out the threads to try and straighten them out but I've not done this as well. I'm in northeastern PA looking for anyone who could lend a hand. |
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The standard bolt is 1/4" in diameter with 28 threads per inch. You need a 1/4 -28 tap to chase the threads. You can get one of these at the local big box store and clean up the threads yourself. While you're there, you can check your various screws and make sure they are the right thread count.
It is very common for the threads in the receiver to be rough and hard to capture, many of us routinely chase the threads on every build. They are also often just not fully cut all the way so some screws are problematic. Remove the handle and make sure you have unobstructed access to the screw drilling. Use a lubricant like kroil or PB blaster generously and be sure to advance and remove the tap multiple times, cleaning the metal filings off the threads along the way. If you use the right size tap and plenty of lube it is hard to screw things up. 1/4-28 tap You will also need a handle |
| It worked, Rick, thank you so much! For anyone else who has this trouble, at first the tap was resistant, and I was a bit afraid to keep driving it in but I did and tested after a few turns with the thinner screw I had from Stag Arms. I was able to turn the screw until I hit a new stopping point. I thought huh, that must be as far as I tapped thus far, as it seemed to be the same length, so I lubed up even more, I went with PB Blaster and boy does that stuff blast! It soaked the lower in all kinds of smelly brownish oil but the stuff really helped the threads as when I went back to tapping, the job seemed a bit smoother. I was seeing shavings the whole time and that worried me as I thought, there's no way I bungled this much aluminum around these threads but i figured well my thin screw was going well, so lets keep at it, I kept up until i got a bit of resistance again and I figured, this is probably far enough to test. I used my thin Stag Arms screw and I was able to thread it almost all the way to the head! Super excited I thought, I got it! Well I tried to use the stupid ass grrr fracking Magpul grip and with my lil head lamp I could see the flesh of the plastic didn't line up very well with the socket itself. I tried to tighten it in anyway and only got about three or four turns in til i felt a bit of resistance and thought. DAMN IT... I'm not going to do this again, I slowed myself down saying, and eased off before I went ham. I looked again and screwed the screw fully on once more to about the head and thought. WTF... Then I grabbed an old grip I had that wasn't Magpul Ninja assassin black majic ready, and low and behold, it fit nice and flush with the socket. Threading was extremely easy this time and i just barely put any force on the screw, threading it completely with new grip. It may be an odd camo for a black rifle but to hell with it. Thank you, thank you, thank you. And I really hate Magpul, I gotta say. |
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Quoted:Thank you, thank you, thank you. And I really hate Magpul, I gotta say. Just an FYI, if you're happy with the feel of that non-black piece of plastic, and really want that super powered ninja black color, then your local grocery and department stores probably have this completely weird thing called RIT dye. It's intended for fabrics, but the dye doesn't know that it's a nylon gun part, instead of nylon fabric. 
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