In a flap

Wed, 14 Jul 2010


These are the rotor parts for the flappy arm model. The core piece is approx 14mm in diameter. I'm still not sure about running square axles in round holes. But I'm not sure about creating circular shafts out of cardboard either. So for the moment I'll stick with the squares.


Here's how it all fits together. It works nicely and has a good range of movement. The mechanism is fun to make and interesting. I'm going to go straight for a completed model. I'll print out the photo above and sketch some ideas on top of it, lets see where we go!

  To receive new blog posts by email

Comments (3)

  • Andrés G. July 15, 2010 at 12:21 am

    Hi Rob:
    I believe you have

    Hi Rob:

    I believe you have been using square axles since long time. I guess that a square axle is a good solution for paper engineering, you may reinforce the hole/bushing with a glued card washer if you are not already doing it. I'm looking forward for the finished model. I have my first model almost ready.

    • robives July 16, 2010 at 7:51 am

      Thanks Andrés – I have used

      Thanks Andrés – I have used either square or triangle axles for most of my models. They do work fairly well but as you say – there is a problem with wear. I'll be experimenting with circle section axles shortly so watch this space.

  • Bo König July 16, 2010 at 6:47 pm

    How about making the arms
    How about making the arms into a pair of dog's ears? Big, floppy ones like on a bassett.

    Then the lifted position might be when the doggy is surprised… (or when passing over a ventilation exhaust grid à la Marilyn Monroe…).

Comments are closed.