Introduction: Sliding Arm Lift, a Knex Ball Machine Lift

Picture of Sliding Arm Lift, a Knex Ball Machine Lift

Hi everyone!

I bring you the instructions for the third new lift first used in my knex ball machine Elysium, the Sliding Arm Lift.

In fact, this lift was used twice in the machine, both were similar.

This is a small, simple lift, and nice to watch.

Its name refers to the arm sliding down every time it has lifted up a ball. This feature is actually really useful and not only a fun extra. The best example I can give is Elysium itself. The second Sliding Arm Lift in the video is located very close to the Ferris Wheel Lift. A normal arm lift could not be placed there, because the arms would have touched the ferris wheel.

The arm uses two black rods. I tested the lift with grey rods instead of black, and it didn't work properly, so the black rods are necessary.

If you build this lift, don't forget to read the image notes in step 5: Arm and Axle, they can be useful. When you have a question or problems while building, feel free to make a comment or send me a message.

Thanks for watching / building!


Step 1: Piece Count

Picture of Piece Count

If you want you can count the pieces before you start building.

Here is a list with all pieces included in this lift, named by their original colour:


Green: 17

White: 17

Blue: 29

Yellow: 12

Red: 6

Grey: 2

Black: 2

Medium flexi: 2

Long flexi: 2

Total rods: 89


Dark-grey: 11

Light-grey: 8

Orange: 8

Red: 12

Yellow: 25

White: 6

Purple: 13

Blue: 1

Total connectors: 84


Blue spacer: 5

Silver spacer: 6

Tan clip: 5

Y-clip: 4

Small blue gear: 2

Medium red gear: 2

Motor: 1

Total other: 25

Grand Total: 198

Step 2: Entrance Track

Picture of Entrance Track

This is the track the balls will follow.

Step 3: Motor and Gears

Picture of Motor and Gears

As the title says, this step shows how to make the motor and gears section.

Step 4: Frame and Exit

Picture of Frame and Exit

The frame and the exit in one step, it's not too big for this lift.

Step 5: Arm and Axle

Picture of Arm and Axle

Look closesly to the pictures. The axle is a bit complicated, but the pictures in this step should help.

Step 6: Finished!

Picture of Finished!

Your Sliding Arm Lift is finished!

Always slide the switch of the motor to the right.

Thanks for watching / building!



dvader1248 (author)2017-09-20

it looks awesome, now i will try it on my totally different ball machine that i built out of a knex rod sorter

Thanks, sounds cool!

KneXFAN200 (author)2017-07-11

I'm going to put this on my ball machine! THANK YOU! Built and done!

Thanks for building!

kalab4 (author)2016-11-26

very nice! straightforward to build and not too many pieces. I will challenge my advanced kinder students (5 yr olds) to try. Only part I know they can't do is snap the axle.

sandroknexmaster (author)kalab42017-07-03

Thanks, wonderful to read your comment! Did they succeed? :)

kalab4 (author)sandroknexmaster2017-07-04

Yes they were very proud of it! One of them said, what he liked best about making it is it was hard, it challenged him and he likes a challenge.

stanthews made it! (author)2017-03-06

I had to modify it to take the clear motor, it works great. Thanks for adding it to instructables.

Looks good, thanks for building!

Haze013 (author)2017-03-02

I made it!

sandroknexmaster (author)Haze0132017-07-03

Thanks for building!

Grasi (author)2016-05-04


sandroknexmaster (author)Grasi2016-08-26

Thank you!

FanPlastic (author)2016-01-31

Mine works just fine, unlike others. definitely going to use it in my next machine.

Good to hear, thanks for building!

Thanks, I used it in regent

master-splinter306 (author)2015-09-20

I love this lift! Keep it up!


No problem, you deserve it!

Linkin_J_Knex (author)2015-09-19

What's the difference between a black and a grey rod?

Blacks rods are stronger and bend less. In this case they also slide better. Build the lift and test both, you'll see the difference.

Built it. Found a second black rod half way through. It doesn't seem to slide back down though?

Thanks for building!

Hm that's weird, you're the second one to say that. Both sliding arm lifts I had have always worked. Maybe the rods are bent?

Nope, perfectly straight. maybe yours are better kept? Anyway great lift but I took it apart :) I motorized my element and will make instructions soon yay! sorry to keep bugging you about it xD

Hm very weird, I'm sorry it doesn't work :(

Don't worry it's fine :)

Ah...I only have grey

Oh I have 1 black

dickheijboer (author)2015-09-21



Lexi Knex (author)2015-09-20

hum i made it (i will take a photo) and i have a little problem my black rods dosent slide

(est ce que je suis supposer mettre de l huile pour que ca glisse mieux )

Hm they should be sliding properly, maybe they're bent? And yes you could try some oil, I don't know if that will work though.

Thanks for building!

Lexi Knex (author)2015-09-19

Nice man i will made it


www139 (author)2015-09-19

whoa! only 198 pieces??

sandroknexmaster (author)www1392015-09-20

Yup :p

Linkin_J_Knex (author)2015-09-19

OMFG second view :D I finished motoring my new element btw. EPIC lift as usal :D Looks awesome!!

0_o Piece efficient AND Doesn't I have all the right pieces to build it (For once) xD

Good, you're going to build it?

Yep :)

*Remove the " doesn't " from last message xD

Thanks! :)

About This Instructable




Bio: Hey! I'm Sandroknexmaster. I like building with knex, especially ball machines. I live in Belgium. I speak Dutch, but also English and French. I ... More »
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