Re: How to build a Baseball Bat Swing Machine

Such a machine would cause some serious safety concerns.  Any contraption
that was capable of driving a baseball any distance would also be capable
of causing serious concussions or worse.  Make sure that your son only uses
this device under adult supervision.

While I don't know of any specific devices to suggest to you; the simplest
way would be to use several screen door extension springs to power a wooden
arm that held the bat. The arm could be a section of 2"x4" lumber. You
would want the pivot to be pretty beefy, at least 5/8" in diameter.  This
whole device would have to be mounted to some sort of table or fixture to
keep the swing plane horizontal. You would have to experiment to find the
correct number of springs, but the following links can help you in spring
selection:
 http://www.ap.smu.ca/demos/content/mechanics/spring_constant/spring_constant.html http://en.wikipedia.org/wiki/Hooke's_law