Step 1: Mods to the Handle
This might be hard to assemble. Insert white rods throughout the handle, and remove the Y connector from the original. My recommended method:
Picture 2: Build the parts like this (Add white rods to the connectors in the middle layer. This isn't shown in the pictures. Make sure you replace the two red connectors in the front of the handle with green connectors.
Picture 3: Different angle
Picture 4: Attach by the middle connectors. You may need to remove one layer first, but reattach it afterwards. Add a blue spacer on the lower grey rod. This will go in front of the white rods that will soon come.
Reattach the green and white rods to the outer layers of the handle.
Step 2: Mods to the Blade
Add 22 orange connectors between the grey rods
Add 8 blue spacers to the front.
Step 3: You're Finished!
Credit to Imperar for the 3d modeled K'nex pieces.
I uploaded the model I used to make the instructions:
With the mods, this is the best K'nex knife on the site so far. It's very sturdy and durable (I've thrown it against the wall a few times, without it breaking.) But try not to stab too hard, because:
A) With enough force at an angle, the light grey connector will snap off and you'll have to gather the blue spacers (happened to me a few times). Ironically, the front is the weakest part of the knife, but as long as it doesn't hit at an angle, it stays on well (I've tested it by stabbing a piece of wood).
B) You might hurt someone if hit in the right spot
I trust you can be careful enough with it.
If it need be said, I take no responsibility for anything done with this knife (or really, the mods).
You might have guessed, but this is my first instructable. Please give advice or corrections. By the way, be as harsh as you want. I like reasoning.