Introduction: Knex Ball Machine - Loopy

About: K'nex is my thing!
Hello folks,

This is a fun little ball machine I came up with a while ago. All one track. Its got an interesting lift, banked turns, and balls never fall off. I have left it on for over an hour without a single ball falling off or other malfunction.

So if you like it, go build it! I warn you though, its a long build, and the instructions are designed more for an experienced builder, so if you've just started with Knex, I'd suggest coming back to this one later.

Thanks, and enjoy!

Step 1: Parts List

A big o'le parts list. You know the screwdriver.


Green - 137
White - 48
Blue - 580
Yellow - 179
Red - 11
Flexi (yellow length) - 8

Dark Grey - 9
Light Grey - 9
Red - 114
Green - 19
Yellow - 38
White - 12
Blue (3d) - 96
Purple (3d) - 392
Orange (tracking pieces) - 93
Blue Spacers - 24
Silver Spacers - 6
Hinges - 1 (if you do use the optional mod, see step 16.)
Tan Clip - 14
Y Connector - 17
Chain links - 38
Some tubing. If you have a set that comes with tubing, you should have enough.
Some tube splicers - at least two, more if your tubing is in shorter lengths.

Grab a cup of coffee, some biccys, put on your favourite music and get rollin'!

Step 2: Lift Area

The part containing the lift and the gearing mechanism. Go!

1-3: Build this panel
4: Build this panel. Same top and bottom as the other one
5: Put them together. All connections are obvious

One down...

Step 3: Gears and Whatnot

The gears that will go into the frame you made in the last step.

1: Your gonna make these three gear bits
2: The one on the right,
3: The one in the middle...
4: The one on the left
5: Snap the middle one into the frame
6: Slide in the one on the right
7: And add the middle on in where shown
8-12: Build this motor gearing thingy. Should be easy. Just wrap the cord around the motor or whatever in a way that does not interfere with the gears.
13: Snap it into the frame there
14: Close up of the connection

Two down...

Step 4: Finishing the Lift

Just a couple more bits and pieces needed to finish up the lift.

1: Make these two pieces
2-4: Make this thing
5: Slide "this thing" into the top of the lift like so
6-9: Add in the two long panel-ish things on either side
10: Make the chain
11-13: Put the chain on


Step 5: Tracking #1

One of many tracking pieces. Get going.

1: Build this part. Remember the blue rods
2-5: Build this tracking piece
6-9: Build this chunk
10: Attach the top tracking to the base, and add on the odd end piece to the larger track portion
11-13: Connect to the lift system. All connections should be simple.

Three down!

Step 6: Track #2

More track. Whoopee.

1-2: Build this bit
3: And this panel
4: Put thems together
5-8: Make this tracking piece
9-10: Add it on top of that chunk you just made

Getting there...

Step 7: Track #3

Just the third track. Small, but more complex than the rest thus far.

1-2: Build this bit
3: And build this one too
4: Connect thems
5: Attach as shown to track piece #2 as shown

Getting there...

Step 8: Track #4

A larger bit this time. Get going.

1: Build it
2-5: Also build
6: Build this warpy bit
7: Add this into the chunk you just made
8: And add the bottom. Should look like this now
9-12: Attach it up to the main lift part. All major connections shown


Step 9: Track #5

No comment.

1: Build this track piece
2: And this base piece
3: Put them together
4: MOD TIME. I made a mistake. Look at that piece I am pointing to.
5: Disconnect the purple with three blues off of the piece I was pointing to, and then rotate the circled purple like so.
6: Put that purple back in as shown. You will need to remove one blue rod from it. Should look like this.
7: Now attach this piece to the main body of the machine as shown

Sorry about that little blunder there folks. Moving on...

Step 10: Track #6

Yup. Track piece 6.

1-5: Big-ole' track piece. Go for it
6-8: The base for that ole' track piece
9: Put them together
10-12: Connect it up to the main part we've been working on


Step 11: Track #7

One long, twisty track section.

1-5: All photos of this one track piece. Do it.

Step 12: Track #8


1: Build this turn
2-5: Build this guy
6: Connect the two
7: Close up
8: Slap on that long windey piece on top


Step 13: Lets Make Some Connections

Basically, just adding the one large piece to the main machine. Why the heck am I giving it its own step? If you know, tell me.

1: Line it up like so
2-7: Make some connections


Step 14: Yellow It Up

Basically, everywhere you could possibly put a yellow rod...Put a yellow rod. It looks cool and adds some strength to the structure. How you put them on does not matter. Just whatever looks cool. You can see what I did for mine, I think it is interesting. All up to you. Enough of this indecision.

Step 15: Lets Go Tubing

Not that kind of tubing...

So lets do this. Start at the top of the lift. Snap in the tubing so that the end is roughly lined up with the end of the first orange connector. Then go. Once you get to the bottom of the lift, push any excess tubing under the chain and wrap it up underneath however you want.

Once you are done, take care to push all the orange track pieces out on the blue rods - they tend to slide into the middle whilst you are putting the tracking on.

Step 16: An Optional Modification

If your balls are falling off the track at the turn after the drop at the top, you made want to modify the first track to be steeper like so. If the balls dont fall off, dont bother.

Step 17: All Done. Go Nuts.

Yay! You're all finished. Good work!

Just like to say thank you for viewing my instructable. And if you're looking at this page, you probably built it too, so thank you! If you built it, and/or have any questions or comments, please feel free to ask.

Happy K'nexing,