Ok you sketchies....I have a Challenge for you...been working on this for a while and I give up. I want to make a model of a hydraulic cylinder...or an object with a hinge on one end and a shaft that moves in and out of the other end... that I can connect to other objects to move them in some fashion.
If I can learn how to use these joints then I can build my Physics test bench. I am always trying to design an arm or something and rather than doing it all on paper....I think Sketchyphysics would be Great.

Thank you so much Mr. Kim! You have been a life saver for me...I now know how to make a "Floating" hinge! I will look forward to more of your helpful videos...

Can one of you experts help me? I have been trying to learn to follow this project from a Youtube video, but the video has no sound and the explainations for what they are doing are tough to figure out. Watched it many times and still will not work properly. Does anyone out there have this Tutorial with sound? Thanks for the help......

http://www.youtube.com/watch?v=3exA1bfA6G8