If you need to drill holes in concrete larger than 1-1/4″ or so, your best bet is a concrete core drill bit. Core drill bits are available for SDS plus hammers, like the Bosch Bulldogs and the Hilti TE-15, and your bigger SDS Max (Hilti calls them a TE-Y) and Spline core hammers. Bits for the SDS plus hammers are available in sizes up to 4-3/8″ and the SDS Max (Hilti TE-Y) and Spline bits are available in sizes up to 6″ in diameter. Most have a drill depth of up to 17″ or so. Most rotary hammer drills show a rating for what size core bit would be at the upper end of the capacity for the drill. I know some contractors that do exceed the recommend size, the key is to work slow and let the tool do the work. As you exceed the recommended size on a core drill bit, you over power the drill and the tool will tend to clutch out more often. Core drill bits on rotary hammers tend to blow out the concrete as they come through the work surface. If that presents a problem, you may choose to drill a pilot bit through the wall or floor and start drilling from both ends. You can find core drill bits for your SDS plus, SDS Max and Spline bits at ConstructionFastening.Net Not sure what bit your rotary hammer uses? Give us a call toll free at 1-877-212-2377.