Introduction: Knex Double Helix Lift

Picture of Knex Double Helix Lift
Since lots of people like this lift, I decided I would make an Instructable of it. This is the first Knex spiral lift that has two spirals instead of one. This allows twice as many balls to be lifted up into the tower than the original spiral lift. It's also the first to use tubing for the spiral, which makes it perfectly round.

This lift is a copy of the one I used in Wipe Out, except it's shorter, it uses a battery-powered motor instead of an electric one, and the tracks going in and out of the tower are different. It can be built with only one spiral, but the bottom where the balls come in might have to be changed. A cool thing about this lift is that the platform and shaft can be on any side of the tower because the double helix is in the center. It's also easy to modify.
This is my first Instructable, and it took me a long time to make because the pictures took a very long time to upload.

Here's all the pieces you'll need to build the double helix lift:

Tan (rigid)-1
Total rods:307

Dark Gray-54
Light Gray-0
Blue 3D-41
Purple 3D-71
Total connectors:262

RC Tubing- 2 pieces, each 3 feet, 5 1/2 inches long
Battery-Powered Motor-1
Black Y Clip-17
Tan Clip-10
Blue Spacer-40
Silver Spacer-28
Small Tan (or Blue) Gear-4
Red Gear-1
Large Yellow Gear-1
RC Tubing Splicer-2
Total other:106

Grand Total: 675 pieces

If you have all these pieces, let's get building!
I hope you like it!

Here's a video of the lift in action:

Click here to view the original double helix lift, used in Wipe Out:

Step 1: The Double Helix, Part 1

Picture of The Double Helix, Part 1

To start out, let's build the core of the double helix. The red rods that help make it sturdy are in a repeating pattern all the way up. The tubing will go on it in the next step.

Step 2: The Double Helix, Part 2

Picture of The Double Helix, Part 2

Now you will put the tubing on the core. Slide the dark gray connectors on the tubing first; then connect the two pieces of tubing onto the core.

You are now done building the double helix; set it to the side and start building the base.

Step 3: The Base, Part 1

Picture of The Base, Part 1

This is the part of the tower that the double helix will be attached to, and it will have all the gears (don't forget the motor). This step is very simple.

Step 4: The Base, Part 2

Picture of The Base, Part 2

This part of the base will hold a big yellow gear. It goes on top of part 1.

Step 5: The Base, Part 3

Picture of The Base, Part 3

This step is very easy. It's just a small section that will go into the side of the base.

Step 6: The Base, Part 4

Picture of The Base, Part 4

This is the final part of the base.

Step 7: Connecting Parts 1-4 of the Base

Picture of Connecting Parts 1-4 of the Base

In this step, you'll put parts 1-4 together to complete the base. Part 2 goes on top of part 1. Parts 3 and 4 go into the side.

Now that you've finished the base, it's time to move on to the bottom of the tower.

Step 8: The Bottom of the Tower

Picture of The Bottom of the Tower

Now it's time to build part A and B of the bottom. Part A is the platform where the balls are loaded onto the double helix. Part B is a track leading to the platform.

Step 9: Connecting the Bottom to the Base

Picture of Connecting the Bottom to the Base

In this step, you will connect the bottom to the base.

After you're done with all that, it's time to build the tower.

Step 10: The Tower, Part 1

Picture of The Tower, Part 1

Now you're going to build the shaft. This is only one side of the tower. Make sure to line up everything the best you can. The two sides of the shaft are different, so pay close attention to the pictures.

Step 11: The Tower, Part 2

Picture of The Tower, Part 2

For this step, build the rest of the tower.

Step 12: Connecting Parts 1 and 2 of the Tower

Picture of Connecting Parts 1 and 2 of the Tower

In this step, you'll complete the tower. Part 2 doesn't have a top or bottom, so it can go on part 1 either way.

Step 13: Connecting the Tower to the Bottom

Picture of Connecting the Tower to the Bottom

Connect the tower to the bottom. Make sure to connect all the rods on the shaft to the bottom platform.

Step 14: The Top, Part 1

Picture of The Top, Part 1

This is the top of the tower where the ball will exit from.

Step 15: The Top, Part 2

Picture of The Top, Part 2

This is the track that balls exit when they get to the top.

Step 16: Inserting the Double Helix

Picture of Inserting the Double Helix

It's (finally) time to put the double helix into the tower. The tan rod should go through the big yellow gear and the base.

Step 17: Connecting the Top Onto the Tower

Picture of Connecting the Top Onto the Tower

You're almost finished! When putting the top on, the yellow rod on top of the double helix should slide into the center on the top.

Step 18: Finished!

Picture of Finished!

Congratulations, you are now finished with the Double Helix Lift!

Just add balls and turn on the motor, and you're ready to roll (well, the balls are, anyway).

If you have any questions, feel free to ask!


The Knex Inventor (author)2016-06-21

Awesome lift! Wish I had that tubing...

Thanks! If you want, you could try to build it with flexi-rods, others without tubing have done that.

I will also look into purchasing some tubing.

Great idea! I will have to try that.

MajesticSepticEagle (author)2016-07-10

I quadrupled the height for my ball machine, but the motor keeps stripping. Is there anything I can do? Please help

Do you mean the motor isn't powerful enough to lift balls up? You could try gearing it down if it has trouble.

thank you so much. What I meant was to put the motor directly on the helix. but I now realize that that would make it worse. I am going to gear it down as you suggested. I could also put a second motor. That could help. Would using one of the wind-up motors help?

Putting a second motor could help, but the windup motors won't do it much good. Just be sure the motors aren't on the same rod, as they most likely won't be the same speed.

I geared it down twice and it now works! thank you so much for your help. Also, do you know of any lifts that are smaller and take up very few pieces? I just need to life the balls about 10 inches.

and my final problem is that the helix bows out in the middle. I plan on putting a guide opposite the track where the ball goes up to keep the helix stable. Does this sound like a good idea?

You could try a guide, if that doesn't work you could try strengthening the helix like this one built by Tornado96:

Cool! As for small lifts, you could try a small wheel lift like the one here. You could also use a small chainsaw lift, as those also don't use much pieces.

Shadowman39 (author)Shadowman392016-07-11

For some reason those links lead to this page... here are the urls.

Also, I love your Kne'x creations.

also the helix won't even spin,but it is not caught on anything. I am just gogin to gear it down.

It might just be too tall, my inverted helix lift would be better at such heights. I never tested making the double helix lift taller than I made it in these instructions.

Thanks :-)

I am thinking of just putting one of the newer green motors on the space directly under the big hyellow wheel.

That would make it harder to turn the helix, so I think you should do the opposite and add another set of gears to make it turn slower.

tytiger33 (author)2010-07-13

Where can you get the big yellow gears these days?

Shadowman39 (author)tytiger332010-07-13

Try eBay.

tytiger33 (author)Shadowman392010-07-13

Thanks knex dosnt sell them any more soo..... yaehhhhhh...........

bartluke (author)tytiger332012-04-13

try knex user group ,they sell everything

That's where i get my parts too


They don't sell them anymore.

Knex .com

MisterBukweet (author)2013-10-13

this lift is by far the best of any helix lifts that I have built... Great design, and look for it in one of my future machines....

Thank you! I'm glad to hear that it works well. Looking forward to your next machine. :-)

In my build, I replaced the dark gray connectors holding the purple RR rail with orange rail connectors.. the balls roll up the lift much smother..

cooljupjup (author)2013-02-21

i`am going to build this soon :D

cooljupjup (author)2013-02-20

works this lift with the newer balls?

Shadowman39 (author)cooljupjup2013-02-20

I think so.

KGuy (author)2012-07-13

Can you use the other type of motor, not the pack?

Shadowman39 (author)KGuy2012-07-14

Yes, but the speed will be different.

sandroknexmaster (author)2012-06-18

Cool, it works realy good!

Thanks, glad it works well. :-)

Gnmar2723 (author)2012-04-21

Shadowman could you make this really tall like 8 red boxes or so? Also please check me out on youtube @

Shadowman39 (author)Gnmar27232012-04-21

It probably wouldn't work if you made it that tall, since the helix wouldn't be strong enough. And I've seen your Youtube channel before, you have some good ball machines. :-)

Gnmar2723 (author)Shadowman392012-04-21

Ok i decided to build the inverted helix instead because its stronger. Thanks a lot i was totally inspired from cataclysm and wipe out! :D

Shadowman39 (author)Gnmar27232012-04-21

Cool! I'm glad you like them :-)

jameshond (author)2012-04-07

can i use big air ball tower balls

Shadowman39 (author)jameshond2012-04-07

I never tested those types of balls, but they will probably work.

jameshond (author)Shadowman392012-04-07

it works i test it and i build this lif it is an cool lift

Shadowman39 (author)jameshond2012-04-08

Cool, thanks!

MegaMetal8 (author)2010-12-22

Would build this if i had the Large Yellow Gear :-(

You don't have a large yellow gear. Ihave six of them.

Thankyou for that. (Sarcasm)

Shadowman39 (author)MegaMetal82010-12-22

You could try to hook up the motor to the axle of the double helix, without using any gears. But the helix will spin around much faster.

MegaMetal8 (author)Shadowman392010-12-23


About This Instructable




Bio: On my page you'll find lots of different Knex projects, from ball machine lifts to useful items. I hope you enjoy!  _______________________ Current avatar ... More »
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