I bought a home last year and have been trying to put up interior walls inside my shop in the back yard. I built a wood frame and want to secure the frames to the concrete floor using masonry screws. The screws came with a masonry bit but I also bought an additional one just in case. My first hole I drilled went about 1 1/2 inches and since then I am unable to drill further than 3/4" into the concrete in multiple spots using both bits. For the life of me I cannot figure out why it can't go any further. I have tried vacuuming away debris while drilling, using oil in case the tip was getting too hot and just increasing speed and pressure in case I wasn't going fast enough. I don't think I am any where deep enough to hit rebar either.
I am completely stumped. Any tips are greatly appreciated.