Should I Buy or Build My Gearbox?

Discussion in 'Gun Building, Modifications & Repairs' started by tim_the_bear, Dec 30, 2016.

  1. tim_the_bear

    tim_the_bear New Member

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    Tim Town
    So I'm looking to make a ground-up DMR and am wondering...should I buy or build my gearbox? I want to learn about how gearboxes work while I do it, but I also want it to work. I've never worked with the internals of an airsoft gun, but can get help from two people who have. I am not restricted by price, but would like to know how much the price difference is. And also, since I am building a DMR, should I make the gun have only semi-auto? I know that a lot of people don't like full-auto DMRs. If anybody has any knowledge on the subject, or knows of good DMR gearboxes, please comment. Thanks!

    --tim_the_bear
     
  2. toobladink

    toobladink Member

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    If you are building a DMR that takes a standard version 2 or 3 gearbox, I would suggest a complete lonex gearbox. They're about $150. All that's left is replacing the bearings, adding a MOSFET, and doing a proper shim job. Oh, and a spring that will yield your desired FPS. AOE is already corrected on these.
     

  3. tim_the_bear

    tim_the_bear New Member

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    Tim Town
    Thank you! I will definitely consider your advice!
     
  4. P4INC

    P4INC Active Member

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    If you're gonna build it. I would get one of those gearboxes that make it easier to get the spring in. I forget what they are called. Either you or someone else will know what I mean.

    I built my gearbox. Just watched a YT video and followed along. Do make sure you release spring tension before opening. An open area with flat surfaces is nice. Cuz stuff will fly out.
     
  5. MNairsoft7

    MNairsoft7 New Member

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    Quick Change (QC) gearbox?
     
  6. P4INC

    P4INC Active Member

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    That sounds right but I'm not 100%
     
  7. Sniper272

    Sniper272 Active Member

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    Hello there, I HIGHLY advocate for building your own gearbox especially for a DMR. DMR's are built not bought and you can build a really solid gearbox for less than the suggested $150 Lonex if you look around. Also, the suggested Lonex shell doesn't even come with everything you'd want in a DMR gearbox. Another thought, having a quick change spring gearbox is nice but also very unnecessary. Don't go out of your way to buy one. I've built several DMR's and could provide you a guideline parts list if you'd like.
     
  8. tim_the_bear

    tim_the_bear New Member

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    Tim Town
    Thanks for the solid advice. I think I will build my own.
     
  9. Twotone

    Twotone New Member

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    Something I'd like to add on the subject of quick change shells is the ease of opening them up when you're testing something, or diagnosing a problem. And closing them ofcourse, we all know what a challenge that can be sometimes :p Also, at least in the Netherlands where I live the national rules state that a single-only DMR is allowed to fire at 450fps, while some fields don't recognise the DMR class at all and limit one to 360fps. Having a QC shell helps tremendously in situations like that.
     
  10. E135

    E135 Active Member

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    Here in the US, semi only AEG's tend to only be limited by the sniper limits, which are usually 500 fps. The challenge with DMR builds is having a decent output, without having too much wear on the internals. Expect to use stock ratio gears with a really good high torque motor, as the tougher springs would require more torque to pull. As far as price, it may be best to wait until you have more experience with gearboxes, and don't you dare throw out those stock gears! It would definitely be cheaper to use stock parts from other guns, as you would then have almost no expense to it. However, if you were to buy and build, it would add up really quickly. Here is the list of parts you would need if you want to go from the ground up, and this is just all off the top of my head:

    -metal spring guide (no ball bearing may be best due to the strong spring)
    -spring
    -piston
    -piston head (if the piston did not come with one)
    -cylinder
    -cylinder head
    -air nozzle
    -gear set (bevel gear, spur gear, sector gear, maybe even the pinion gear on the motor)
    -tappet plate
    -tappet plate spring (can be hard to find)
    -selector plate
    -selector plate spring (tends to come with the plate)
    -cutoff lever
    -safety levers
    -safety spring
    -anti reversal latch
    -arl spring
    -trigger contact set
    -trigger contact spring
    -trigger
    -trigger spring

    That is not even including all the screws and the wires. That is why it is good to already have extra crap to salvage. I would encourage you to learn about AEG internals and tinker what you have, then use the stock pieces that you have replaced, and purchase boneyard guns for the gearbox screws and more salvageable parts to piece together the DMR, which is really just a harder hitting AEG with more care towards the hop up.
     
  11. P4INC

    P4INC Active Member

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    Make sure you have it "permanently altered" to semi auto. Or else it's an AEG at lost fields
     
  12. toobladink

    toobladink Member

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    I think what you should consider is durability and consistency. That's all that matters with this type of gearbox build. I suggested the lonex because it makes it extremely easy. I would highly suggest lonex compression parts, and one of their gearbox shells. They're very strong and durable, with allows stronger springs without the need for a sorbo pad or airpad.

    If you're building your own, are you going to buy all the parts separately and build from the ground up? Or use an existing gearbox in a current gun?

    I also think QSC is rather useless. I've only found it truly helpful in builds where I need to fit in a strong spring, usually M160+
     
  13. tim_the_bear

    tim_the_bear New Member

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    Tim Town

    I'm a planning on buying a Lonex 8mm V2 Gearbox Shell for $50, and then fill it up with SHS, Lonex, and Prometheus Laylax Parts, mostly. I'm also going to use some smaller and less important parts from an old gearbox. And thanks for the advice! It was extremely helpful!
     
  14. Businsky

    Businsky Member

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    I second the post about buying a complete Lonex. Brillarmory.com has them for a great price. Lonex shell as well as their internals are mid to top of the line. When you buy everything it will equal what a complete one costs. Then just add a mosfet and shim like they mentioned. You can even get them in different gear ratios such as 13:1, etc. this forum us all the threads to rewrite and install a mosfet as well. I've also figured out hat mixing and matching parts often makes it a little tougher to get things to fit/mesh perfectly.
     
  15. Sniper272

    Sniper272 Active Member

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    It might equal what a complete one will cost but you're not paying for what you don't need. Does he need the stock wiring without a mosfet? No. Is he going to swap out the piston for a full metal tooth one? Yes. Right there you already have another $40ish in parts on top of the initial cost. OP, here's a short list of parts that I'd recommend.

    Dboys complete gearbox (Shell is super strong and can be used or replaced but you get all the bits inside the gearbox as well, replace with lonex if you want to but I see no need to do it immediately if at all)

    SHS 12:1 gears (Great trigger response at a great price)

    SHS blue piston (Strong full metal tooth piston)

    Steel bushings (Doesn't matter too much the brand although Lonex and SHS are good ones, these are less prone to deforming unlike brass ones)

    O-ring air nozzle (simply helps with consistent FPS)

    SHS piston head (helps with compression and consistency, don't get a metal one or one with two O-rings)

    Mosfet of your choice

    High Torque Motor (paired with the low ratio gears will give you great trigger response.

    Ball bearing spring guide (keep torque tension from building up in the spring)

    M150 spring (aprox. 500 FPS with a .2)

    If the Dboys gearbox has any of these parts already such as steel bushings or ball bearing spring guide then you have no need to buy those. Also if you want to buy upgrade any extra parts then go ahead. This whole list of parts should only cost about $130 and you've got a really solid gearbox. Just make sure to check out the stickies on how to shim, lube, radius and correct AOE and you'll be good to go!
     
  16. toobladink

    toobladink Member

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    Lonex completes have a great FMR piston and piston head pretty much corrects AOE for you.

    $130 for some china gearbox,

    Or $200 for a full quality build. Maybe even less if you buy some parts used, like the motor, or the complete gearbox. That extra $40 you were talking about is more like an extra $10, because he can always learn how to make a MOSFET. Or choose to not go with one at all.

    You also dont need the gears. Just a low TPA motor will increase trigger response enough because of the overspin.