Air percussion rock driller. 2:18 video:
https://www.youtube.com/watch?v=ipk1rLXoJDA
More: TERRA-JET 3008 ES pit launch machine
Previously:
https://www.homemadetools.net/forum/...515#post155011
https://www.homemadetools.net/forum/...830#post129255
https://www.homemadetools.net/forum/...244#post116078
https://www.homemadetools.net/forum/...414#post101520
https://www.homemadetools.net/forum/...3602#post99570
https://www.homemadetools.net/forum/...1250#post74040
