Mini crossbow for NERF dart

A NERF dart compatible mini crossbow that does not need any extra part other than the printed ones and a regular rubber band (and the NERF dart…duh!).

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Description

After numerous iterations of thoughts, plans and models, I finally started designing this mini crossbow for the #3dpgnerf4um2 competition, hosted by 3D Printing group of Facebook. I wanted to accomplish three specific things with this project:

  1. Make some that is kid friendly and can be used as a toy
  2. Make it as simple and fun to build as possible
  3. Use little to no parts apart from the printed ones

And I ended up designing this mini crossbow.

A simple crossbow would be truly a boring thing to design or make so I wanted to add a bit of extra to it. So I ended up designing a mini crossbow that have manual forward/backward motion via four wheels, left/right and up/down via manual gears. This models put a check mark next to all the three things that I planned on incorporating: it is kid friendly (and can be very colorful!), it is simple, yet fun to build (you will see!) and it uses only a regular rubber band (and the NERF dart; couldn’t do anything about it). A quick rundown of the model is given below:

https://c8.staticflickr.com/9/8056/29219078343a65cc7ab1bb.jpg

Despite looking very simple (which was one of the goals), the model had to go through quite a few iterations before I felt like it’s ready to be entered for the competition. The following picture is in memory of those parts who helped prototyping the project; you parts are awesome! Couldn’t have done it without the sacrifice from you parts :)

https://c3.staticflickr.com/9/8089/29809819466c75967b9f9b.jpg

I haven’t been 3D printing for that long, probably for few months until now and since this is my first 3D printed functional model, I became very excited once it was working. Since I couldn’t find anyone to ask for their opinion on how it is, I resorted to some things that I already have:

https://c2.staticflickr.com/9/8184/2921908819396ea817594b.jpg
Credit: Loubie @ Thingiverse

https://c7.staticflickr.com/9/8521/29809829206726bbf9b55b.jpg
Credit: 3DBenchy

https://c7.staticflickr.com/9/8094/298098269666fb71e8351b.jpg
Credit: MorenaP @ Thingiverse

https://c3.staticflickr.com/9/8051/297321998420c583a568db.jpg
Credit: SpierceTech @ Thingiverse

https://c8.staticflickr.com/6/5130/2921909894348d3c64388b.jpg

https://c1.staticflickr.com/9/8033/29732194392c999d4b9ffb.jpg

Materials and methods

For making this model, you will need the following:

1. A 3d printer or you can always ask someone to print the parts for you.
2. A heat gun/hair dryer to do some fun fittings.
3. A rubber band of correct size and tension (once you make the model, you will be able to find the right one for it).
4. Last but not least, zeal!

Here’s what I have used:

https://c5.staticflickr.com/9/8138/29809808076_c26fa83324_b.jpg

For the 3d printed parts, few of the parts will have to be printed multiple times (or multiple at one time) so here is the list of parts that you need to print:

X1 Base
X1 Crossbow Body
X1 Gear 1
X2 Gear 2
X1 Release Hold Pin
X1 Release
X1 Support Left
X1 Support Right
X2 Updown gear
X4 Wheel cap
X4 Wheel
X2 Wing

Assembling them together should be pretty simple and hence I did not put up an instruction for it. Once you have put on the four wheels, heat up the four wheel caps enough so that the caps are slightly soft but not too hot to get deformed (please don’t let kids do this). Once it is soft, put on the wheel cap on the portion protruding out from the wheel. Once the caps cool down, it will have a (to some degree) permanent fit and won’t come off. Heat gun will need to be used for release pin too. The release pin will need to go through either one of the holes at the rear portion of the crossbow body, then through the release pin and out through the other hole. When the release pin is slightly protruding out from the other hole, heat it up enough so that it is soft and slightly press it (using something since it will be hot!) against the crossbow body to seal it off. See, it is fun setting up the model :)

I have tried to keep the model as easy to print as possible but there is quite a significate bridging that needs to be done by the printer while printing the crossbow body. You have been warned!

I have made the parts to accommodate the tolerance of my printer so prints from other printers may or may not print well enough so slight adjustments using heat gun and hobby grade knife might be needed.

Alongside, some of the parts like the Updown gear is meant to be snug fitted so that the crossbow body doesn’t fall down on its weight.

Loading the crossbow should be very straight forward:

1. Aim using the gears (or manually if you feeling lazy).
2. Pull the rubber and have it rest on the small protruding shape near the release.
3. Load your NERF dart
4. FIRE! (using the release…duh!)

Here is the link to the video of the crossbow in action:

https://www.youtube.com/watch?v=Iasy4pHdnd8

As mentioned before, this is my first 3D printable model so there might be some mistakes and I do apologize for those. I would love to get your feedback on what needs to be fixed and how the model can be improved further.
Hope you liked it 

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Comments

Fd269a77ccfb56aea4b5d30e4bd6d2d5?default=blank&size=40andres lopez added this to the Cosas bacanas collection ago
A2ad4e358d33dbb9be26b1fbcb31fd11?default=blank&size=40Fernando Miras Sosa added this to the Juguetes collection ago
47c3b9cab1ad3ac94d09f4bef22e7d5f?default=blank&size=40mrhasan commented ago

Thank you :)

0d6e98cc4dfc4053c18c926ce1b800ef?default=blank&size=40ChatToBrian commented ago

Very nice design. Love it.

47c3b9cab1ad3ac94d09f4bef22e7d5f?default=blank&size=40mrhasan published this design ago