Klingon OTF Dagger

Good for cosplay, Halloween, or just fidget.

Patterned after the D'k Tahg weapon.

Remix of David6722's excellent OTF knife here: https://www.thingiverse.com/thing:3619717 (Update: David's knife seems to no longer be there; try https://www.thingiverse.com/thing:3668073 for a remix)

The model shown is printed in CC3D Silky Silver PLA and Solutech Black PLA.

Video of how it operates: https://youtu.be/yHsj8J9V-wY

Follow print settings recommended for the original. 35% grid infill and no bottom solid layers creates a nice outer textured appearance for the upper and lower case halves.

Mirror the right blade to get the left blade.

Center part of lock spring may need sanding to make it fit into lower half of the case, but that insures it will be snug

Assembly is the same as the original, except for the two secondary blades that engage rack-and-pinion teeth on the slider.

The case is held together with five 2x5mm metric screws. You COULD just glue the halves together, but you will eventually need to open the case to change either the spring or the rubber band, so it is best to use screws.

Getting the extend/retract to work reliably can be a bit tricky. You need to push the thumb slide with one quick motion, all the way to the opposite end stop. Do not hesitate, or the slider will interfere with the lock spring achieving a positive lock.

If it still does not work, you might try bending the lock spring so that the ends have a more aggressive bend toward the blade.

Tip: To eliminate friction and make the knife work more reliably, use a candle to rub some paraffin onto the sides and edges of the blade. Do this also on the secondary blades and their pivot points. You may need to ream out the holes in the blades if they don't rotate easily. If the case binds them, back out the screws a tiny bit.

Update 9/6/2019: Made some adjustments to the screw holes after I had some trouble with the holes being too small for some screw heads. New upper case and lower case files.