Re: blasting smallish tunnels in hard rock

"Richard Smith"  wrote in message news:m1o7b49gna.fsf@void.com...
What the granite looks like can be seen in my webpage on
boulder-splitting
http://www.weldsmith.co.uk/tech/minerals/240314_rocksplit/240314_rocksplit_drill_feathers.html
The split sections...
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Congratulations on your successful innovation that leaps a major hurdle.
When the corded hammer drill proved useless on granite I was lucky enough to be given the big Makita (to fix) which drills 1/2" (13mm) holes into granite adequately, and my jobs are close enough to the house to not need cordless tools for the harder slogging in granite or 1" holes in oak.
I didn't know there was an application for a close quarters masonry drill. I've used right angle drills only between house studs and under cars. The contractor bought the Makita and a long 1-1/4" bit for plumbing and wiring holes through concrete foundations. It takes spline drive bits which are becoming rare, he replaced it with SDS Plus.
SDS = Steck-Dreh-Sitz, Insert-Turn-Seat.