Knex Ball Machine 'scissor Arm' Element

About: 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't work, of course. All my knex stuff is creative common, an...

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.

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Step 1: 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

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

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

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    5 Discussions


    4 years ago

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

    1 reply

    Reply 3 years ago

    The ball needs to build momentum before entering the element.

    (Sorry for necropost)


    4 years ago

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