K'nex Flywheel Powered Machine Gun

Please read this whole intro before you ask questions in the comments (I know it's long but this gun deserves it).

Let me introduce to you the first ever flywheel powered k'nex gun. Instead of most guns where you pull back rubber bands that push a ram rod that shoots a rod, in this gun there are 2 motorized wheels that propel the ball forward much like a pitching machine or a battery powered Nerf gun. This mechanism makes it much easier to create a true semi-automatic or fully automatic gun.

I originally made this to practice my ping pong spikes (that is why it shoots ping pong balls) but I thought this "gun" was extremely innovative so I am posting it in hopes that someone will develop this mechanism into a better gun that actually shoots k'nex. If you do develop this, please give me some credit because I introduced this idea, (if someone else actually came up with this before me, please let me know). Also, if you develop this please use a stronger motor! This machine only shoots the balls about 5 feet (I know, it's a bummer) because the power all depends on the motor (there are no rubber bands required) and we all know how powerful k'nex motors are. Like I said, this isn't made for performance, it's mainly just to introduce the idea of a fly-wheel powered gun. This machine uses a standard green k'nex motor, just about the weakest out there, so I only got the wheels cranked up to about 900 RPM, or about 15 rotations per second, and with around 2 inch diameter wheels, the edges are traveling about 7.85 feet per second, which is only about 5.35 miles per hour. With a stronger motor, you could get this going much faster, and probably turn it into an actual gun that shoots real k'nex.

I do strongly recommend that you build this, even though it isn't really an actual gun, because it is insanely cool to watch the 2 wheels shoot the ping pong balls. I made 2 sets of directions, so if you don't want to build the whole gun you can just make the mechanism and save a lot of time and pieces. If you do only make the mechanism, though, you will have to hand load each individual ball into the wheels to get it to shoot. If you do have all the pieces, or you just want to make something cool, you can make the whole gun. This includes the shooting mechanism, the feeding mechanism, a stand, a magazine that holds about 22 balls, (this is easily extendable or optional) and an optional funnel to make it easier to load the balls. Overall, you can fit about 40 or so balls into the magazine and the funnel, but the funnel will not constantly feed the balls into the magazine, because they will get stuck. Because of this, only about 22 balls will get fed into the shooting mechanism at a time. This is why there is a huge magazine on top of this gun. I would have made the gun hopper fed instead of magazine fed if the balls didn't get stuck. The feeding mechanism controls the feeding to about 1 per second, so they all don't get shot out at once. You could easily modify this to make it into a faster firing machine gun or a semi-auto with a trigger. I just wanted to keep it at a relatively slow rate of fire.

For some reason this gun is very picky about the size of the ping pong balls used. The smaller the better, I tried some slightly bigger balls and they didn't fit. The orange ones in the pictures are Kevenz 50 pack training balls. You can get the whole pack for around 3-4 dollars.

Lastly, this is my first instructable, so please comment and tell me what was good in this ible and what I should change for my next. I know the k'nex instructables days are pretty much over, but I would like to keep them going. Although I only joined instructables recently, I have surfed around this website and built pretty much every ball machine, gun, roller coaster, or cool contraption on the site. So I am not new to instructables, I just only decided to join recently.

Sorry for the terribly long explanation. Congrats if you made it this far. I just thought this gun deserved to be explained so I won't have to answer thousands of questions in the comment section. Alright, let's get building!

Note: Be sure to either read the image notes, or the numbered directions at the bottom of each step. (Or you can read both, but they say mostly the same things).

This gun uses a lot of pieces, but you can substitute many of them. There are 2 piece counts, one for just the mechanism, and the other for the whole gun.

Important Note: In this gun, there are an absurd number of y-clips, metallic blue clips, one slot grey clips, etc. This is only because this gun needs a lot of spacers to function and I ran out of spacers about half way through designing this so I substituted them with small clips, which I happen to have a lot of. You can substitute many of the clips in this piece count with more spacers, or other clips. I will specify where in each step.

Piece count for just the mechanism (picture 2)

Connectors:

• Dark Grey (1 slot): 10
• Red: 6
• Yellow: 11
• Green: 10
• Light Grey (2 slot): 2
• White: 24

Rods:

• Grey: 4
• Red: 5
• White: 12
• Blue: 32
• Yellow: 22

Other:

• Small Triangular panel: 4
• Standard Grey Wheels (Picture 6): 4
• Wide Thin Tires (Picture 7): 2
• Micro Black Rods (Picture 3): 2
• Orange 1-slot Tubing Connectors (Picture 5): 3
• Y-clips: 36
• Micro Chain Gear (Picture 4): 1
• Large Yellow Gear: 4
• Metallic Blue Clips: 5
• Small Gear: 4
• Motor: 1
• Tan-Clip: 9
• Blue Spacers: 36
• Grey Spacers: 42

Grand Total for the Mechanism: 290

Piece count for the whole gun (including the mechanism)

Connectors:

• Blue 3D: 8
• Purple 3D: 40
• Light Grey (2 slot): 20
• Dark Grey (1 slot): 85
• Red: 36
• Orange: 42
• Green: 48
• White: 96
• Yellow: 120

Rods:

• Grey: 33
• Red: 59
• Yellow: 65
• Flexible Orange (Yellow Rod Length): 4
• White: 130
• Green: 204
• Blue: 127

Other:

• Micro Chain Links: 54
• Micro Chain Gears (Picture 4): 2
• Micro Black Rods (Picture 3): 2
• Large Yellow Gear: 4
• Medium Red Gear: 1
• Small Gear: 5
• Metallic Blue Clips: 16
• Standard Grey Wheel (Picture 6): 4
• Wide Thin Tires (Picture 7): 2
• Orange Tubing Clips (Picture 5): 3
• Tan-Clips: 15
• Small Triangular Panel: 4
• Motor: 1
• Y-Clips: 47
• Grey Spacers: 57
• Blue Spacers: 69

Grand Total for the Entire Gun: 1,406

This is the mechanism for this gun. If you want, you can build just this but you will have to hand feed the balls into the machine. Many Y-clips are used in this step, and you can interchange most of them for spacers. You will need two micro black rods to lock the wheels to the gears, and you will also need two of the wide thin tires that fit two standard grey wheels inside of each of them.

1. What you will make this step
2. Make this
3. Make 3 more
4. Make this
5. Attach them like so
6. Make this
7. Attach it like so
8. Another view
9. Make this
10. Another view
11. Another view
12. Attach it
13. Another view
14. Make this
15. Another view
16. Another view
17. Attach it
18. Another view
19. Gather these
20. Put the 2 wheels inside the tire
21. Build this with the wheel you just made
22. Another view. Be sure to put this micro black rod inside the hold in both the wheel and the gear
23. Build this
24. Attach it
25. Make another
26. Build this. You can use spacers for the Y-clips. The orange tubing clip is helpful if you have it as it is extra wide so it spreads the Y-clips out more
27. Build this. You can use spacers for the Y-clips
28. Build this. You can use spacers for the Y-clips
29. Attach it
30. Build this
31. Attach it
32. Attach this
33. Attach this
34. Build this
35. Another view
36. Another view
37. Make this
38. Another view
39. Attach it
40. Attach it
41. Another view. Make sure you put the blue rod in place
42. Attach the wheels
43. Another view
44. Another view
45. Done!

This is the system that feeds the balls one by one into the flywheels. It is a long step but important.

1. What you will make this step
2. Make this
3. Make a second panel, but make it a mirror image of the first one
4. Make this. You can use spacers instead of the 4 gray clips
5. Another view
6. Make this
7. Make this. You can use spacers instead of the 6 gray clips
8. Connect them together
9. Another view
10. Attach them to the second panel you made
11. Another view
12. Another view
13. Another view
14. Attach the other panel on (the first one you made)
15. Build this
16. Build 2 of these
17. Make this
18. Attach them together
19. Another view
20. Attach this to the track you just made
21. Attach what you just connected to the frame section
22. Another view
23. Another view
24. Build this
25. Another view
26. Another view
27. Make these
28. Connect them to the axle like so
29. Connect 54 micro chain links together
30. Attach the chain to the wheel. It doesn't connect to anything else yet
31. Build these
32. Build this
33. Build these
34. Connect them
35. Connect them
36. Build this
37. Another view
38. Another view
39. Connect them
40. Connect them
41. Another view
42. Another view
43. Build this. The 3 dark grey clips in the middle can be spacers instead
44. Connect them
45. Gather these
46. Clip these on the front
47. Clip these on the back
48. Another view
49. Attach the axle to the track you just made
50. Another view
51. Attach the bottom part of the magazine you made to the feeding system you just made
52. Another view
53. Another view

You finished the feeding system! I promise it gets easier from here.

This is the top half of the magazine for this gun.

1. What you will be making this step
2. Build this. You can use spacers instead of the 6 gray clips snapped on to the white and blue rods
3. Another view
4. Another view
5. Another view from the back
6. Build a second one, but make it a mirror image of the first one
7. Make this
8. Make this
9. Another view
10. Connect like so
11. Connect like so
12. Build this
13. Another view
14. Build this
15. Another view
16. Connect like so
17. Another view
18. Build this
19. Build this. You can use spacers instead of the 2 y-clips for this
20. Another view
21. Connect like so
22. Another view
23. Make 2 of these
24. Make this
25. Connect like so
26. Make this
27. Connect like so
28. Another view
29. Connect these pieces together
30. Another view
31. Another view
32. Another view
33. Put the other track piece on
34. Another view
35. Another view
36. Another view
37. Attach the cover to the magazine
38. Done!

This is the front stand and support for this machine. The reason there are these pillars is to take the weight off the mechanism and put it on the stand at the bottom. This lets the mechanism run smoothly. If the pillars weren't there, the motor wouldn't be strong enough to power the machine because of the weight on it.

1. What you will make this step
2. Make 2 of these
3. Make 2 of these
4. Gather these
5. Connect like so
6. Connect the others like so
7. Another view
8. Make this
9. Make this
10. Make this
11. Another view from top
12. Connect the first 2 together
13. Add the 3rd on. The 2 orange connectors on either end must be perpendicular to one another
14. Make this
15. Connect like so
16. Another view
17. Make a second one
18. Gather these
19. Connect like so
20. Connect to the pillars
21. Gather these
22. Connect like so
23. Connect like so
24. Another view
25. It should look like this. The pillars are supposed to bend
26. Connect them to the base
27. Another view
28. Another view
29. What it should look like now

This is the rear stand and support for the machine, probably the easiest step. If you don't have an orange rod (red rod length) you can just use a red rod.

1. What you will be making
2. Make 2 of these
3. Gather these. If you don't have the orange rod, you can use a red rod
4. Connect them to one side panel as shown
5. If you are using the orange rod, be sure to connect the yellow connector to the outer slot in the orange rod
6. Put the other panel on. The panels should not be parallel to each other, they should instead veer apart from one another
7. Make sure you connect the yellow pieces to the outer slots, so the panels get spread apart
8. A view showing how the panels are supposed to spread apart

This step is optional, but it is useful and looks cool. I suggest you build it.

1. What you will make in this step
2. Make this
3. Make another
4. Make this
5. Make this
6. Make a second, be sure it is a mirror image of the first
7. Connect them
8. Build a second one
9. Connect them
10. Another view
11. Build this
12. Build a second
13. Build this
14. Another view
15. Build this
16. Another view
17. Connect them to one panel
18. Put the other panel on
19. Another view
20. Another view
21. Get these
22. Connect them. You only have to connect them in 6 places
23. Another view
24. Another view
25. Another view

You finished all the building! Now it's time to put it all together!

Yay! you built everything. Now the fun begins.

1. Gather all of the parts of the gun
2. Put the mechanism and the front stand together
3. Another view
4. Attach the feeding system
5. Another view
6. Another view. Make sure to attach the chain to the other gear, and to put it around the protruding rod
7. Another view
8. Another view. Make sure you attach the three gray clips to the blue rod
9. Another view
10. Attach the rear stand
11. Another view
12. Another view. Add the two grey spacers onto the red rod
13. Attach the magazine
14. Another view
15. Another view
16. Attach the funnel
17. Another view
18. Another view

You're done! This is the part where I say that I am not responsible for any damage done by this gun, but let's be honest, this thing isn't going to cause damage any time soon. Go have fun with it. Practice your ping pong spikes, turn it into a semi-auto gun, or experiment with it and mod it. There is lot's of potential for this gun. (I would love to see someone turn this into a ball machine lift!) Note: This gun is very picky about the size of the ping pong balls used. The smaller the better, as slightly bigger balls might not fit down the magazine. I used Kevenz 50 pack training balls. You can get those for about 3-4 dollars per 50 balls. Lastly, please comment if you have any questions.

- Jessbuilt