I have a Ramset Hammer drill with the Hammer drill option set, speed set at low , and a new 1/4" masonry/concrete bit. I can't get more than an 1/8" in about 15 minutes of incremental drilling with wax and cleaning. I have tried other area's and in the foundation wall and got the same result.
The drill is in forward and in hammer mode, thank you -). The drill is not cordless, but I have had it for 30 years when I use to install Kawneer and Vistawall Curtain walls and skylights (commercially).
The bit still has the hammer flutes/blades and the are not chippedits new.
There isn’t any aggregate in the wall that’s what is odd, it’s like a solid slurry of Portland cement. - think plaster consistency, tough stuff in 3 of the four walls tested. The drill is in hammer mode the select switch mode is set and on setting 1, low speed to prevent over-heating of the bit.
I’ve drilled steel I-beams with this drill up to 1/2”, and modern concrete (90’s) with the same bit type, the drill it’s just like a Hilti, same bits will work. I got them from ‘Fasterns inc.’ [mobile construction delivery service]. Thanks for the feedback and thoughts, much appreciated.