I am in Indonesia. I previously rented a jack hammer, which ended up costing around $175 for a week. The jack hammer appeared to be an old Hitachi H65.
We wanted the jack hammer to break limestone rock, and for concrete.
The jack hammer completely failed to do anything with the rock. I suspect this was because in Indonesia there is a great tendency to cut corners with poor quality tools; in this case the bit (not an original part I guess) seemed to be of very soft metal, so it was useless.
Now we are in the position where we need a tool to break relatively substantial quantities of rock, say a cubic metre or more off of a much larger (say 200 cubic metres) rock. And we also want to drill a rock to insert 16mm steel rods.
So I am looking at buying a larger rotary hammer, which is likely to be a Makita or Bosch, as that's what's generally available here. Labour is cheap here (less than $10/day), so there's not a great payoff in spending more money to save time - the machine just needs to stand up to the job.
Is there a strength the machine needs to have to destroy my rock? And what kind of technique and bits should be used to break the rock?