Make a K'nex Custom Attachment for Your Nerf Blaster!




About: Hello! I'm Nerfrocketeer, also known as Nefrock', Nerf, or NK. I am an avid fan of Nerf wars, engineering, and animal activism (but no I don't go overboard). Thank you for A MILLION views (woah!) and making ...

In a Nerf war, it is important to be able to use your Nerf blaster to the best of your ability. Though many blasters come with high performance right out of the box, it is sometimes necessary to take matters into one's own hands via various attachments sold separately. There are plenty of options, from fore grips, to stock extensions and aiming devices.

Even so, sometimes the attachments you can buy just aren't enough...

K'nex, as usual, can solve the problem. The small versions of the classic rods and connectors for children (also known as micro-K'nex), can easily be used to build a customizeable reverse tactical-rail to go on any Nerf blaster, with any type of attachment.

This guide shows just one example of the many, many variations of attachments you can build using the simple NK3AE K'nex Tac-Rail system.

Step 1: Pieces

To build this version of the K'nex Tac-Rail system, which is based off of a basic red-dot sight, you will need;

  • Nine black connectors.
  • Two blue large hole connectors.
  • Two red connectors.
  • Six grey connectors.
  • 24 Yellow connectors.
  • One orange connector.
  • Two green loop connectors.
  • Four tan "Y" connectors.
  • One black cap.
  • Eight purple rods.
  • One red rod.
  • Three yellow rods.
  • 27 black rods.
  • You will also need a Nerf blaster with a tactical rail on the top (for a scope piece).

All of these pieces are in micro-K'nex, so colors may vary. The shape and orientation of each piece is what's important.

Step 2: Reverse Tac-Rail; Part One

The Reverse Tac-Rail pieces are the perfect width and shape to easily slide on to a Nerf tactical rail while providing a secure fit.

To build the basic components of the reverse tactical rail, attach two yellow connectors to a black connector using two black rods, as shown in pictures 1 and 2. Repeat this process to create a total of eight pieces as in picture 3. Also create two similar pieces, but with blue large hole connectors in place of black connectors as in pictures 4 and 5.

Step 3: Reverse Tac-Rail; Part Two

Connecting all of the pieces from the previous step will give them the stability necessary to create a snug fit on the tactical rail of any Nerf blaster.

Add a purple rod to each of the openings shown on a reverse Tac-Rail piece with a blue large hole connector, as shown in pictures 1, 2, 3, and 4. Next, add two green loop connectors to the purple rods indicated in pictures 5, 6, and 7. Then continue adding reverse Tac-Rail pieces in the order shown in pictures 8 and 9. Finally, spread the pieces evenly out on the purple rods, as shown in picture 10.

Step 4: Attachment Sides

The sides of the attachment will give it a realistic look and feel while adding accuracy and stability.

To build the sides, attach one red connector to one grey connector using a black rod as in pictures 1 and 2. Next, add two tan "Y" connectors as in pictures 3 and 4. Rotate the "Y" connectors 90 degrees as shown in picture 5. Add another grey connector using a black rod as in picture 6, and add a yellow connector and a yellow rod as in pictures 7, 8, and 9. Repeat the process to get two identical sides (picture 10). Add the sides to the reverse Tac-Rail piece as shown in pictures 11 and 12; the green loop connectors should connect to the yellow rods as shown in picture 13.

Step 5: Adding the Orange Sight Piece

The orange sight piece will greatly increase accuracy. The crossbar will add rigidity to the attachment, and the dial will give the piece a realistic feel.

First, add a red rod to the scope as shown in pictures 1 and 2. Next, add a grey connector to each side, making sure they are facing in the proper direction, as in pictures 3, and 4. The dial comes next, add it to one end of the red rod from the beginning of this process, and secure it with a black cap, as in pictures 5, and 6. Finally, add the orange sight piece to the front blue piece using a black rod, as shown in pictures 7, 8, 9, 10, and 11.

Step 6: Locking Security Pin

The locking security pin helps keep the attachment from sliding off of the tactical rail when the blaster is in use.

Connect two yellow connectors using a yellow rod, as in pictures 1 and 2. Next, add two purple rods, as in pictures 3 and 4. To store the locking security pin, slide it through the openings of the yellow connectors on the reverse Tac-Rail as shown in pictures 5, 6, and 7.

Step 7: Attaching to a Nerf Blaster

To add your attachment to a Nerf blaster, simply extend the locking security pin, slide the attachment on the tactical rail of the blaster, and hook the pin around the rear of the tactical rail. Lock the pin in place, and the attachment will be secure.

NOTE: The blaster shown is a Nerf Elite Alpha Trooper CS-12. Blaster styles may vary.

Step 8: Attachment Complete

You now know how to build your own K'nex Tac-Rail piece and scope attachment! Customization is easy with the NK3AE K'nex Tac-Rail system, and many more types of attachments and accessories can be made! Thank you for reading this guide, may your foam wars be fun!

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    29 Discussions


    1 year ago

    Cool! i would make it, but i don't have the pieces.

    the glasses kid 05

    3 years ago

    i didn't have the pieces, so i did a different variation for my stryfe.


    Reply 4 years ago

    Instructables author MyOmy has made a few of those already! Check out his page for some awesome stuff!

    (I'll make one eventually as well, though).

    Make sure you hook it over the plastic nubs at the end of the tac-rail and that shouldn't happen. :)

    Thanks! Your attachment? I'm not sure what you are referring to. Perhaps you meant 'any' attachment? If so, yes any attachment, grips, scopes, sights, bayonets, masterkeys, and so on will work with this system, provided you know how to build them! ;)

    Actually, I meant the attachment that was in my Nerf Reflex modifications Instructable . You actually commented on it, so I thought you would know what I meant. Then again, it was posted almost two years ago. :)