[epic]

Just went to the inlaws for a small christmas thingie and they bought me a tip-up called the "jig-up". Basically its an automatic jigging tip up. I couldnt find it online, but I'm sure they bought it somewhere in Pueblo since they live in Ordway. Anyways I'm posting it to show the simplicity of the design, its ran off 2 D cells and if you made the jiggin machine the same way it would be pretty simple.

 

[epic]

A longer shaft and a bigger spring would do it I think... I posted it for an idea, since it looked pretty simple to me. Trail and error is going to be your best method to pin down the feel you want.

 

[epic]

how about a small vaccum pump then? design it with air pressure? Then you can have more then 2 speeds depending on how good the vaccum pump can move a piston.