Hammer drills are fine for making small holes in masonry for 1/4″ anchors and screws. But they are not up to the task of anything more serious. They use a friction plate to generate the impact force. I literally burned out two hammer drills trying to move a 1″ masonry bit through cinderblock before learning the limits of that technology.
For serious drilling or chiseling into stone, masonry, or concrete, you need a rotary hammer. I bought the bargain-priced Hitachi DH24PF3 a few years ago (available for under $170 from many online resellers) based on a comparative test published by Tools of the Trade, where it won their 2005 Editors’ Choice Awards. Their summary:
Hitachi’s powerhouse DH24PC2 rotary hammer wins for being unstoppable. In our January/February 2005 issue, our tool tester reported there was little he could do to slow this rotary hammer down drilling and chipping in 3,000-psi concrete. From recommended pressure through extreme force, the unit relentlessly and quickly sank 1/2-inch-diameter holes and blasted a bull-point chisel 3 inches deep. Add to that good comfort, low reaction torque, and a competitive price and the result is a tool that can tough it out in the roughest conditions. The DH24PC2 weighs 5.5 pounds, delivers 2.1 foot-pounds of impact energy, and has three modes of operation [(drilling only, hammering only, and drilling plus hammering)].
I subsequently used this rotary hammer for hours straight to bore through a concrete slab, footer, and compressed shale beneath as I was installing a sub-slab suction system for radon control. It also easily blew through 10″ block walls to make a 4″ opening for the PVC vent.
The tool uses standard SDS-Plus bits. An excellent source for bits is Bullet Industries.