Introduction: Falling Arm Lift, a Knex Ball Machine Lift

Picture of Falling Arm Lift, a Knex Ball Machine Lift
Hello fellow knexers!

Finally, after a long time, I managed to find some time for this ball machine lift.
The Falling Arm Lift was first seen in my knex ball machine Paradox.
This is the second new lift in a series of 4 new lifts, all from Paradox.
It's a nice lift, with an average piece count for it's height.

However, this lift doesn't always perform very well. The version I used in Paradox worked at 99%, but the second version I made only worked at, let's say, about 70%.
I want to be honest and tell this to you before you start building.
But why making instructions if the lift doesn't work very well?
1) Sometimes it does work, so you can always try.
2) Some knexers requested instructions for this lift, so I'm sure some of you are going to build it.
3) Lifts can always be modified.

If you build this lift, read every image note! It will help you a lot!
If you have any problems or questions, feel free to comment or PM me.

I hope you like it, and 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 color:


Green: 92
White: 31
Blue: 71
Yellow: 69
Red: 61
Tan: 1
Grey: 35

Total rods: 360


Dark-grey: 17
Light-grey: 11
Orange: 35
Red: 39
Green: 10
Yellow: 68
White: 14
Purple: 74
Blue: 17

Total connectors: 285


Blue spacer: 62
Silver spacer: 56
Tan clip: 19
Y-clip: 10
Blue hinge: 1
Black hinge: 1
Small blue gear: 5
Medium red gear: 5
Big yellow gear: 2
Medium hub: 1
Medium tire: 1
Motor: 1
Rubber band: 1
String: 1 meter

Total other: 166

Grand Total: 811

Step 2: Arm Catcher

Picture of Arm Catcher

This part will "catch" the arm.

Step 3: Entrance

Picture of Entrance

Here the balls will wait to enter the arm.

Step 4: Combining Arm Catcher and Entrance + Adding String

Picture of Combining Arm Catcher and Entrance + Adding String

First we'll combine the previous steps, after that we'll add the string.

Step 5: Connection Support

Picture of Connection Support

This is the easiest step, it will connect the entrance and arm catcher with the rest of the lift.

Step 6: Gears

Picture of Gears

The gears are very necessary to move the arm.

Step 7: Crank

Picture of Crank

This is the crank, it will pull the arm to the top and then let it fall down.

Step 8: Motor Section

Picture of Motor Section

This part contains the motor and the rest of the gears.

Step 9: Tower Support

Picture of Tower Support

Time to make some height!

Step 10: Exit

Picture of Exit

Here the ball will exit the lift.

Step 11: The Arm

Picture of The Arm

The arm carries the ball to the top of the lift. This is the very last step!

Step 12: Finished!

Picture of Finished!

Congratulations, your Falling Arm Lift is finished!
Always slide the switch of the motor to the left!

You can always send me a picture when you've built this lift so I can add it to this step.

Thanks for building / watching!



LindaP5 made it! (author)2015-10-01

It's fun!

sandroknexmaster (author)LindaP52015-10-03

Thanks for building, does it work well?

kirogn (author)2015-09-19

love it cant wait to get to work

sandroknexmaster (author)kirogn2015-09-20


www139 (author)2015-02-12

What about it specifically doesn't always work?

sandroknexmaster (author)www1392015-02-13

Mainly the entrance mechanism. It doesn't always work correclty, sometimes the ball didn't roll to the basket.

www139 (author)sandroknexmaster2015-02-13

oh. It's still a REALLY cool lift! :)

sandroknexmaster (author)www1392015-02-14

Thanks :)

sandroknexmaster (author)2015-01-10

Thanks! :)

cooljupjup (author)2014-01-08

nice lift! i really like it, im going to build some of your lift as soon as possible, but one question: does this work with the white-black balls?

I didn't try it, but it should work with blackwhite balls ;)

Oh I forgot to say that you probably have to mod the exit :P

DarkOwlProductions (author)2013-12-22

Yes, you've done it! It looks wondrously complex and beautifully mechanical. Good job. :p

Thanks! It's not THAT complex ;)

Shadowman39 (author)2013-12-18

Nice! I've probably said this before, but my favorite part is the second joint. :-)

Thanks :D

You're welcome, also, that crank is pretty thick. :-P

Yes it has to be, I tried to make it smaller (wich is better), but this was the best way to do it :p

Yeah, it makes it nice and strong.

JonnyBGood (author)2013-12-19

Straight forward mechanical genius

Thanks a lot :D

No prob! Commented, watched video, slapped by ingenuity, Complimented.
I need to read and watch video first than comment... in that order.XD

Haha that's how checking out an instructable works :D

JonnyBGood (author)2013-12-19

Alright! something else I want to build! Good job getting featured too!

Thanks! :D

hunter999 (author)2013-12-19

Wow this is awesome - well worth the wait!! I may use this in my future knex ball machine sinc I have already selected the lifts to include in my current one! Also congratz on the feature, you deserve it!

Its a shame this lift did not work 100% though :-(

Thanks :D

hunter999 (author)hunter9992013-12-19


Sorunome (author)2013-12-18

I liked that lift in your ball machine :)

Haha thanks :-D

Also, congrats on the insta-feature ;)

Thanks again :p

hehe, your welcome :P

Oh, and congratulations on your 5th ball machine lift! Quite an achievement! :-D

I have 2 more lifts standing in my room, ready to make instructions.
BTW the next is your freefall wheel lift :p

*Ahem* Did I say five lifts? Ah, short-term memory...
Looking forward to see what you did for the next one. It seemed to work far better than my version, so I can hardly wait to learn more! :-D As each lift comes out, I become more certain why Paradox won the contest. ;-)

It will be a bit different from the version in Paradox: The ball will roll to the center instead of falling, but it still looks a lot like your original concept.
Yes, Paradox won for a reason ;D

Ok, this lift was amazing in Paradox, and still looks pretty awesome in action! :-D Thanks for the instructions!
P.S: Do you have any idea why it worked 99% in Paradox but dropped in reliability when rebuilt? Where is the main weak point? (I would build it now to find out, but another project is in the works. ;-) )

The problem is the string: it has to be the exact lenght as the version in paradox.
It was quite difficult to find a way to explain it in an instructable, but then I found a way (locking the entrance and arm catcher, step 4)
And sometimes the ball didn't exit, but if that happens to someone they just have to tell me, now I know how to fix that problem.

Makes sense. It's so good to know that if anyone has problems, you already have the troubleshooting answer! ;-)

Haha, always a step ahead ;D

TheAwesomestDude (author)2013-12-18

luv it


dickheijboer (author)2013-12-18


Thanks! :D

Maybe I gonna use it for my next ball machine.. :)

Cool! But don't forget what I said in the intro...

Yeah, I've read it, but the lift looks so cool.. :)

Haha thanks! :p

dr. richtofen (author)2013-12-18

I love it. Not a ball machine builder myself, but I love how it works.
Great job!

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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