lima-x / lego-technic_da-otf

A Lego-Technic Dual-Action Out-the-Front Knife [DA-OTF]

Lego-Technic Dual-Action Out-the-Front Knife [DA-OTF]

A proof of concept DA-OTF Knife made out of Lego-Technic Bricks. Powered by an ~12N Spring and two Rubberbands.

Content:

• .lxf File for Lego-Digital-Designer [LDD]
• .7z File containing Building-Instructions [HTML-Page]

Note:

I basically build this just for fun inspired by an Video on YouTube with the intention of making it compacter, smaller, more powerful and overall just better. This is the result of three days of development and two additional days of testing and upgrading. And I think it turned out pretty well, though it still has some problems caused by the compact Internals (see under "known Problems").

Additional Note:

I normally wouldn't publish something like that, but it turned out so well that I decided to make it publicly available with some half decent Documentation.

Information on what spring I used will follow sometime soon (meaning probably not. If thats the case follow the Information for a suitable spring):

Strength: ~ 10N - 12N

maximum diameter: 7mm

neutral Length when build in: 55mm

stretched Length when build in: 85mm

When building it your self you will also need 3x Pin Connector Round 1L (Tube Ø 7,84mm 1M) [Item: 18654] (this part isn't available yet in LDD)

Assembly and Demonstration:

(yeah, the Image is a link to a YouTube Video)

Known Problems:

• When sliding the Switch don't press too strong down on it, it will cause friction in the Internals and the Blade could get stuck while free floating.

Possible Fix: Just reset it manually by pulling out or pushing in the Blade all the way

• When sliding the Switch make sure to push or pull it straight, sliding it diagonally will cause friction in the Internals and the Blade could get stuck while free floating.

Possible Fix: Just reset it manually by pulling out or pushing in the Blade all the way

• Uses some rare Lego-Technic pieces aswell as an spring and rubberbands with specific measurements, which aren't even Lego pieces.

Possible Solution: NO

• Difficult to assemble/disassemble because it's so compact and powerful and therefore needs so many Connector-Pins to hold it together.

Possible Solution: Use a less powerful spring aswell as weaker rubberbands and use less Connector-Pins, but I can't guarantee you that it will either still work or if it will "disassemble itself" :D