please clarify why we should tell you how to make this item, you dont seem to have shown any experience or aptitude for magic on this forum as yet.
but ok get yourself a big long spring, fix it to a board and sit on it.
the resulting experience should focus your mind and allow you to refrase the question, perhapse you could say I'm new hear and would like to build my own raven but dont have the faintest idea what it is or what it does, and i dont want to fork out a whole £20 to get a thingamy gig as you could tell me how to do it for free.
or alternativly send me £25 and i will mail you all the details and a working version to practice with

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