Introduction: Knex Stair-Arm Lift

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Hello everyone! It's been a while since I built this lift in Citadel, but the instructions are finally here! The main things I like about this lift are its advantages over my original stair lift: It has less friction so it can go higher, and the balls lift from one "stair" to the other at an angle of 45 degrees rather than 22.5 like in the normal stair lift (and you can make the angle go even higher than that). It works very well at the base of a machine, but can look good anywhere. Like most lifts, it can be extended, and it has the added bonus of working with the newer Knex balls as well as the older ones.

Here's a video of the lift in action (direct link):

If you'd like to partake in the building of this lift, let's move on to Step 1! (I'm sure you know what it's about)

Step 1: Acquire Pieces

Here are the pieces you will need to build this version. As always, you could take shortcuts to use less pieces. Just be sure to take the right shortcuts, or else you'll end up in the middle of the Canadian wilderness.

Rods: 237







Connectors: 202

dark grey-28

light grey-3








Other: 69

blue spacer-32

silver spacer-20

tan clip-4

small blue/brown gear-1

medium red gear-1

small wheel-3

small tire-3

medium wheel-2

medium tire-2

newer-style battery-powered motor (green)*-1

Total: 508

*You can use a different motor if you wish, but you'll have to modify the motor section.

Step 2: Base and Crankshaft

Wow, already beginning the mechanics? You bet! But, you won't be adding the motor till the end, so you won't get to see it move yet (I know this is torturous, but be patient). The crankshaft is located at the bottom, so it'll be the first thing you build.

Much like my last Instructable, with all the pictures, there's an image note that explains the particular picture, rather than a list in the step description like I used to have. This way you won't have to constantly close full-screen mode to read the explanations. You'll be able to save time by doing that, and use it in other ways -- like for reading this sentence.

Step 3: Base Structures

These small tower sections will hold the arms, and whatever else you decide to add to it later. Just don't sit on it or something. Start from one end of the base and work your way to the other end. Lastly, you'll add some rods to the crankshaft to prepare for installing the arms.

Step 4: Lower Arm

The lower arm is special, so he gets his own step all to himself. There is a counterweight on the back that accounts for not only the weight of this arm, but the other ones as well. It doesn't really need the counterweight, but the movement of the lift will be smoother with it included.

If you make your lift with an even number of arms, you can leave the counterweight out and still have smooth movement. But, to go all out, I would recommend adding small counterweights to each arm so each arm balances out on its own. This will reduce the stress on the crankshaft, especially if you make the lift have many arms.

Step 5: Upper Arms

These arms are exactly the same, so you'll end up repeating what you did for the first 7 pictures. Like the last step, at the end you'll build the support sections and attach the arms.

Step 6: Entrance and Exit

Unless you want to manually place the ball in, you'll need these small track sections. Thankfully, this version of the lift doesn't need a gate at the beginning like the original had.

Step 7: Motor

The end is approaching, but first add the all-important motor. Perhaps more important, however, is the blue gear that you'll build first. I'd recommend you put batteries in the motor first, or else you'll get super excited to turn it on and have it do nothing, thus extinguishing your excitement.

Step 8: You're Done!

Great job, builder! You have finished the Stair-Arm Lift. Now you can press the switch in either direction and watch it run. As I usually say, if you have any questions/comments/concerns, leave a comment below. If you want your lift featured on here, click the "I made it" button and upload a picture!

Thanks for viewing, and happy ball-machine-building!