Introduction: Knex Ball Machine 'scissor Arm' Element

Picture of Knex Ball Machine 'scissor Arm' Element

This element uses a 'scissor lift' geometry to move the ball sideways while acting at a small arm.

Attached is a small video of it in use.

Step 1: Scaffold

Picture of Scaffold

Here is the important part of the scaffold. Don't worry if it doesn't balance like in the first picture, as I added hidden unneeded pieces to hold it up.

Step 2: Pivot and Counterweight

Picture of Pivot and Counterweight

This part holds the pivot point and the counterweight. I used 2 pulleys (1 1/2 in), 1 snap-on hub (1 1/2 in), and 1 tire (1 1/2 in).

Step 3: Scissor, Wheels, and Ball Holder

Picture of Scissor, Wheels, and Ball Holder

I have not tested other sized scissors, but if you do then you should build a further track in step 1.

After this step you are done! Good job


Linkin_J_Knex (author)2015-10-30

the ball isn't heavy enough. I tried different counterweights but it still doesn't work :(

The ball needs to build momentum before entering the element.

(Sorry for necropost)

martijnb95 (author)2015-04-17

I would have thought that the friction were too high for this. apparently it works though :)

sandroknexmaster (author)2014-11-30


Gargamel-Knex (author)2014-11-24

Cool ball-element :-)

About This Instructable




Bio: I'm into knex ball machine stuff. My favourite parts are lift/element hybrids, probably because I tried building a perpetual ball machine. It didn ... More »
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