AUG Bolt Mod

Discussion in 'Gun Building, Modifications & Repairs' started by ThompsonFTW, Oct 26, 2011.

  1. ThompsonFTW

    ThompsonFTW New Member

    So I was asked to do a guide on how exactly the bolt mod is done on the AUG. (Used to replace that POS “motor plate”). I will be including pictures that will pretty much explain it, but I will also be talking my way through the procedure. Anyways let’s get started.

    Does your “motor plate” look like this? [​IMG]
    Does your entire gearbox move when you pull the trigger? If you answered yes to either of these questions it’s time for you to begin the journey to a more reliable solution.

    First things first, you will need, a bolt, a nut, (I used stuff I had laying around, note I didn’t use a nut…) and a drill. Once you get everything together you’re going to want to remove the “motor plate”. Once done with that mark where the gearbox sits when all the way forward in the body. [​IMG]
    This is where you will be drilling through. Once you’re done with that start you’re drilling (remove the gearbox…), you want it to be as straight as possible and if you’re not quite straight it is better to be slanted towards the gearbox.
    Once done it should look like this.

    Now you will notice in my pictures that I have 3 more holes surrounding my larger hole. That is because I used a wood screw (?). It has three prongs on it. Here is a picture of what I used. [​IMG] Works really well because the threads are hidden in the body. This keeps the gun looking sleek…Much better than a nut. However if you don’t have any wood screws lying around a nut will work. In the picture you will notice one is longer than the other. That is because I had to take a hack saw to it to make sure it wasn’t to long. To do this you will simply screw it in making sure it isn’t to tight and mark where it is a little more than flush. Take it out and cut it off. (Mine needed grounding on the ends after cutting to insure it would easily go into the “cap”) Should look like this by now.
    You’re almost done! Now all you have to do is insure that the gearbox is seated all the way forward. To do that put the gearbox back in the gun. Press it all the way forward and insure that the bolt you have installed applies enough pressure to keep it there. (It doesn’t have to be “exact” but you want it to be pretty close otherwise you will have air leaks) If it’s not applying the pressure needed don’t freak out! There is an easy fix. All you have to do is insert the bolt halfway, (not into the “cap”/nut) and wrap it with electrical tape until its snug. This will push the gearbox forward that extra little bit. (I don't have a picture of this step because I didn't have to do it...) Hope this helped some of you wondering what I am referring to when I say the bolt mod.


    Thanks to 1Whitekid and Tackett.
    Last edited: Oct 26, 2011
  2. L5132

    L5132 New Member

    Looks good! I now understand what you meant, lol :)

  3. Tackett

    Tackett New Member

    I superglued some sorbo to the back of the gearbox where the bolt contacted it to make it even tighter.

    Thanks thompson.

    Oh and, not to be nitpicky, but you think you could change the title? I thought this was like modification to add a faux feeding bolt or something.

    Nice job bro.
  4. need2airsoft

    need2airsoft New Member

    Like that, gonna get stuck into it in the morning, thanks for posting dude!!
  5. cool4christ

    cool4christ New Member

    Very good thanks and I would also like to add that the "wood screws" are called t-nuts but other than that very nice.
  6. IHOP

    IHOP New Member

    Here's my type up from where I posted it in ASGIF's mini-mod thread. Slightly different.

    I have another mod for an AUG to fix the broken/sheared/cracked "motor plate" that you might find on an AUG from the AS Megastore bone yard. This "motor plate" as they call it just holds the gearbox tight with the receiver. This can also be done with an AUG that doesn't have a broken motorplate to free up some battery space.

    1)Acquire two allen screws long enough go about half way through the receiver at the point right behind the gearbox. Leave a few millimeters space between the receiver and screws. You'll also need a bolt coupler the same inner diameter as the allen screws.

    2) Measure the distance inside the receiver from the end to the part of the gearbox you want to secure it at. I put it in the middle part below where the spring guide would be.

    3) Mark on the outside of the receiver where the bolt should go.

    4)With a drill bit slightly smaller in diameter than the allen screws you chose, drill trough both sides of the stock at the same time to ensure the holes line up. try your best to keep it as horizontal as possible.

    5) With the allen screws, screw them into the holes partially. The holes shouldn't be so much smaller than the screw that is a job on its own to screw them in, but small enough the fight tight. Attach the coupler between the screws. You'll probably need a wrench to keep the coupler from spinning while tightening the screws.

    If it doesn't keep the gearbox snug in place, you put the hole too far back. Have no fear, for electrical tape is here! If that occurs, just take the screws out and wrap the coupler in enough tape so it pushes the gearbox all the way forward. After that, you might need to use a bigger wrench to tighten it, or cut enough tape away from the center of the coupler so the wrench fits while retaining tape on the sides to push the gearbox. I'm not sure how well the tape method would work with the coupler since I got it pretty much perfect the first time.
    It frees up a fair amount of battery space. I have no reference to how much since I never had the plate in to begin with, but I've talked with other people that have done this, and they say it frees up a good amount.
    It looks very clean on the external side.
    Last edited: Feb 18, 2012