A2 front sight post pins

Discussion in 'AR-15 Discussion' started by TheDaggle, Jun 25, 2010.

  1. TheDaggle

    TheDaggle Member

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    Alright, FTF, I need your wisdom. I'm trying to get a free float onto my upper, but my front sight pins have drawn a line in the sand. I've damaged 3 punches, and chipped away at the post, but the pins will not relent!

    What do I do? Heat it up? Freeze it? Yell forcefully at it until it gives way to the sheer gravitas of my persona?

    Picture 94.jpg
     
  2. willshoum

    willshoum New Member

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    No body likes to put heat to a rifle barrel. But you can heat the parts you need to if you submerse the barrel in water and only heat the part thats needed. Some times steam will do the trick in stead of a blow torch.
     

  3. Dillinger

    Dillinger New Member

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    Daggle - You have to remember that a lot of those pins are conical ( tapered ) and only go in and come out one way!

    You can apply heat very lightly by using a soldering iron on the pin itself, but you might want to turn the sight over first and give it just a light rap and see if that makes any difference.

    Gentle is the key word here. You don't need to MONGO them out, if they aren't moving, there is a reason why and another method of finesse is needed. ;)

    JD
     
  4. TheDaggle

    TheDaggle Member

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    I'm fairly certain I have the right end. it LOOKS smaller than the other end, and I've borrowed a block of some sort that's intended for this type of thing with "pins out" stamped on the side that I was using...
    Wouldn't heating the pin expand it, wedging it in there even worse?
     
  5. Dillinger

    Dillinger New Member

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    Some companies put them in with a low grade Loctite. Heating the pin will help release the agent, plus the site tower will dissipate the heat, pulling it away from the pin.

    These pins are a pain in the ***, but eventually you will be able to get it. :)

    JD
     
  6. TheDaggle

    TheDaggle Member

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    Thanks. I put a soldering iron to the pin for a while, but I didn't seem to be getting the pins very hot... I believe I'll have to come back to it tomorrow.

    I AM a little disappointed that the gravitas of my persona didn't do the trick :(
     
  7. Dillinger

    Dillinger New Member

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    Daggle - I hate to mention this, because someone will come along and tell you a thousand reasons why it's abad idea....

    HOWEVER - Do you have access to a drill press, a mill, or a level and a real steady hand?

    Because you can select a drill bit that is JUST BARELY bigger than the center hole in the roll pin ( and I am talking by the thinnest of hairs here - insert actual mic'd size of pin here ) and remove some material from the inside of the pin, thereby making it a tad more brittle. The heat from the drill bit will also work on any locking agent and you should be able to thump it right out with a solid hammer and a punch.

    In the times I have been in the shop, this process has been used, maybe twice, and both times it was on older units that just would not give up the ghost. :eek:

    Just a thought...

    JD
     
  8. Quentin

    Quentin New Member

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    Now that's a great idea, JD! Definitely need a soft, careful touch but it should work.
     
  9. Glasshartt

    Glasshartt New Member

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    Daggle, the pins should go out left to right and in right to left.
     
  10. Gatekeeper

    Gatekeeper New Member

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    When I took my FSB off I set it in between blocks of wood, I set a large punch on top of the small end of the pin and give it a hard wack. Reset the punch and wacked it again until they broke free. I'm not talking about lightly tapping it out, all you will end up doing is peening the ends of the pin over.
    Tapered pins are like wedges. To get them started I had to really smack 'em with a 12-14oz. hammer. Once started then they tapped right out.
    Soaking them with PB Blaster (or other penetrating oil) overnight may help

    I may have misunderstood Mr. Dillinger's suggesting drilling out the center of the "roll pins". They are solid pins holding on the FSB.:confused:
     
  11. Dillinger

    Dillinger New Member

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    Really? Huh. Well, I was thinking roll pins, which are very common in a lot of AR's that I have worked on.

    If you have solid pins, that is even better, as they are not self expanding like a roll pin does.

    Choose a very small drill bit and drill the center out of the full pin. But I would not do it by free hand. I would definitely opt for a drill press at the very least.

    Then saturate heavily with a penetrating liquid like Mobil 1 Synthetic and whack it with a good sized hammer and a brass punch.

    JD
     
  12. TheDaggle

    TheDaggle Member

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    50 tons.

    I took my upper to an engineer/machinist recommended by a gunsmith I consulted. He put my sight post in a press, and tried to punch it out. Nothing. So he milled a custom punch with a concave tip and tried again. He bent the punch and muttered, "That shouldn't happen. Hmm." Next he milled a sturdier concave tipped punch and a custom block to hold it steady, and tried again. Nothing. Finally he put a hardened steel T block on the pin, and put it in his heavy duty, no-bull**** press. The pins finally yielded to 50 effing tons of pressure. Even once he had 'broken the seal', so to speak, he still had to go back to his smaller press to get the pins all the way out. Del-Ton does not intend for their products to be disassembled.
     
  13. slowryde45

    slowryde45 New Member

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    Forgive me if this was already suggested, as I came in late on this one...but did you ever contact Del-ton directly and ask them how the pins were installed and how they get them out? Just curious. Everything you went through almost seems like they were welded in or something.
     
  14. TheDaggle

    TheDaggle Member

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    They said that the muzzle devices were fastened with loctite, everythin else should be normal. I guess they just don't mess around when they install pins... The machinist was blown away.
     
  15. slowryde45

    slowryde45 New Member

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    Wow, I think that's the first time I've ever heard of anyone going through all that you did to get the front pins out. I don't know if that's a tribute to the way they build their uppers or not - it sounded more and more like they were welded in or epoxied. But hey, my hat goes off to you for sticking with it to get 'er done ;)
     
  16. willshoum

    willshoum New Member

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    Loc Tite

    Hind sight is 20-20, A cigarette lighter would have worked in this case. 400 degrees would have broke down the Loc Tite and the pins would just tap out. :) Ps Iv'e got 4 pics of a machinist that was caught up in his work but never blown away!
     
  17. TheDaggle

    TheDaggle Member

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    No, the pins in question did NOT have loctite, just a crap load of pressure. The flash hider has loctite.
     
  18. Troy Michalik

    Troy Michalik Is it Friday yet? Supporter

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    No worries Daggle, Del-Ton made up for it on mine. They forgot to put a pin in it at all and I had to send it back. It was a close one too. I didn't see it until I was bore sighting the red dot I had just put on it.