On Sun, 15 Aug 2010 17:14:50 -0400, Bob Engelhardt
wrote:

Ignoramus7071 wrote:
...
Anyway, today I thought, what if I make a smaller version of a diesel
hammer, ...

Here's a smaller, propane version (for driving fence posts):
http://www.youtube.com/watch?v=MhJxn...eature=related

Ouch, lifting that 45 pounds each time you want to drive a t-post
would wreck you as bad as hammering with the 20# manual driver.

This one requires a gas compressor, but it's lighter @ 28#.
http://www.youtube.com/watch?v=rEAgOKem48g