Easy Knex Elastic Band Crossbow

This is a series of easy to follow images that show how to build a simple knex crossbow.

It fires well and accurately, but to get the right length of elastic band you may have to tie elastic bands together.

You will need:

elastic bands (big and small)

knex pieces


It took me 2 hours to design, build and modify.

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Step 1: Trigger Mechanism (top View)

The cogs can be held in place by small elastic bands.

Step 2: Trigger Mechanism (bottom View)

Step 3: Loading and Firing.

push the trigger into firing position, pull the elastic onto the tape and attached to the small red snapped band, then pull the trigger.

Step 4:

1 Person Made This Project!


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4 Discussions


3 years ago

It is stronger than u think, especially my advanced model


3 years ago

I have also made a more advanced, better version, may release that sometime.