This is a fairly simple knex grenade that is pretty powerful for its size. It only uses 12 pieces and 2 rubber bands. Sorry if this is anyone else's, it might have already been made due to its simplicity...
This will NOT blow up when you have the second rubber band (the purple one in this picture) on, take it off to activate it!
Step 1: The Pieces
Red connector x 8
White connector x 3
Blue rod x 1
Rubber Band x 2 (if you try it with 1 it will be very hard and it won't have a safety mechanism)
Step 2: Putting It Together
Okay, tke the red connectors and attach them to a white connector like so. (pic 1)
Then, wrap a rubber band around all of the red connectors. (pic 2)
Next, add the other two white connectors to the top and bottom of the device. (pic 3)
Finally, place the grenade on top of the other rubber band and pull the rubber band up through the spaces between the outide rubber band and the white connector on opposite sides. Thenput the blue rod through both loops. (pics 4 & 5)
Now you're done!
Step 3: Priming and Detonating
To prime the grenade, simply take off the outside rubber band CAREFULLY. Now it's armed.
Chuck on the ground for best power! Have fun!