Notice before you buy!
The product does not come pre-assembled. You are only paying for the printed parts.
Parts will arrive connected by small lines of plastic. These can be removed by a knife or wire cutters.
Expect lots of sanding and cleaning of the parts.
Rubber bands/springs, screws, and string are not included.
For my version, I used #2-56x1 bolts with corresponding nuts, size 8 rubber bands, fishing line, and superglue.
The blade shown in the video was a prototype and the design has changed slightly since then.
The video is merely a quick overview of how the parts fit together. It is not intended for a detailed tutorial.
Do not buy unless you are familiar with the mechanisms!