Hair trigger guide for V3 gearboxes

Discussion in 'Gun Building, Modifications & Repairs' started by Kujis, Jun 1, 2016.

  1. Kujis

    Kujis New Member

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    Kihniö
    At first I'd like to point out that hair trigger for AEG's isnt in anyway my own intention so all the credits for it go to Suzaku from airsoftforum (http://www.airsoftforum.com/board/topic/198550-aeg-hair-trigger-guide-necro-exempt/) I also want to credit Coldfusion from airsoftsociety for his great guide (http://www.airsoftsociety.com/forums/f10/coldfusions-aeg-hair-trigger-guide-113219/) and Maekiis rambling videos (https://www.youtube.com/channel/UC47U_j0ZrS8cPazS_OhYNww). This post isnt about inventing the hair trigger, just my way of doing it to V3 gearbox that has different kind of trigger mechanism than V2 gearboxes.

    This is my first post here as I have just been freeloader for years and using other ppls knowledge without posting any of mine but now that i got few V3 gearboxes to do this mod to and realized there really wasnt much guides I decided to post one. Hopefully this is of some help to someone.

    You must have MOSFET installed to your aeg and some knowledge about tecching before attempting this mod.

    I do not take any responsibility if you mess your gun while doing this, it worked on me but there can always be some errors.

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    I will be using LCT As Val's gearbox for this mod, it has some minor differencies to standard V3gearbox, such as safety and fire selector, but they wont affect to making this mod.

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    First open the gearbox and take out the trigger mechanism, there is a ton of guides for this already so I wont focus on that more.
    While taking off your trigger mechanism you notice how far away the sledge in the middle is from contacts in un modded mechanism, our goal is to make that distance a lot shorter.

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    Take the contacts out of mechanism and shorter them the amount you feel like is the best, pay some attention at this since if you cut them too short your trigger might not reach them anymore. I cutted them right after the opening starts to close. You should also file some material off from upper side of contacts, as shown in picture, this will shorten the contact time and prevent random bursts and other problems.

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    You want the contacts to be the exactly same length since the opening will be gone the sledge might not be able to go between contacts anymore so it needs to hit both of contacts at exact same time.

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    Next we need to limit trigger's backward movement, for this we need to add something behind trigger's second part (the metal colored one in picture).

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    I did this by drilling hole behind second part and adding 2mm thick iron wire to it. You should pay tons of attention for positioning this hole since if its too front the circuit cant open and with very narrow space you will also have to be very precision with modding the cut-off and safety, there will be more of this later. If you drill the hole too far away back it will kill the whole point of hair trigger so do use some time for positioning this. As you can see from picture I drilled little bit too high and had to file the wire down a little. Better way of doing this might also be adding threads to hole and putting screw there since it will probably last longer than super glue that i used to hold the wire down.

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    Next we need to add something in front of trigger sledge to prevent it move too much forwards and thus preventing cut-off from working, this isnt exactly must do thing since contacts should prevent sledge from moving too much front but it will remove the malfunctions incase it manages to slip past.

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    I did it again by drilling hole and adding 2mm thick metal wire to it. Pay attention that whatever you use to prevent sledges movement doesnt touch the contacts since it will cause the circuit to close continuously. Also keep in mind while drilling the hole that the sledge needs to hit the contacts.

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    Next we need to limit the trigger sledge's movement so that it can't get too far behind and escape from our trigger wich cant reach all the way back anymore. Again i did this by drilling hole and adding some metal wire as pin, suprise suprise. You can also do this by adding some material behind the sledge and that way preventing it from moving too back. You don't want to glue that pin since then you cant remove the sledge from inside the mechanism anymore, so rather just make it fit in there perfectly and the gearbox will hold it in its place. ¨

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    As you can see from the previous image the sledge is now permanently in forward position and the cut-off lever cant get over it anymore and full auto won't work. To prevent this you need to file off pice from sledge to let the cut-off get over it, dont file too much as cut-off won't work anymore if you do. You can also modify the cut-off lever but i chose to modify the sledge as plastic is much easier to work with and this way you can keep your cut-off lever in original shape.

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    Now we should have ready trigger mechanism so you can assemble the gearbox. Last thing left to do is to modify the safety pieces so that the black part can move to it's place and prevent the trigger from moving, you will most likely have to modify both parts depending on how forwards your trigger is.

    Remember to test your build with multimeter every once in a while to see that everything is working. Always make all the measurements and placings with gearbox closed to make sure thay everything is in it's own place.

    As I said that this is my first post and i have only done very few of these so there most likely is better ways to do things, this is however something to start with and improve it as you go. English isn't my first language so I apologize for types and weird words, hopefully you guys still get the point and that this guide is for some use to someone.
     
  2. Sitting_Duck

    Sitting_Duck Well-Known Member

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    270
    Thanks for taking the time, done a v3 - not exactly hairline trigger but a definate improvement over the very slack long travel 2 piece trigger system

    thanks again for such a good detailed tutorial on your methods used
     

  3. Kujis

    Kujis New Member

    6
    0
    Kihniö
    Glad that someone liked it. And yeah it's pretty hard to get it as good as V2 but I managed to get mine down to 3mm trigger pull (somewhere around 0.1") and it could get little better still by shimming the two trigger pieces so they wont wobble so much, havent yet figured good way for this though.