Is it the drill or the bit?
they drilled the mortar just fine. They also have been used for drilling metal and wood just fine too.


They are probably ordinary "HSS" drill bits mainly intended for drilling metal but also usable for wood (and, with care and low speed, most plastics)

HSS bits will get blunted quickly if used to make holes into mortar or brick. You can sharpen them if you have some suitable tools.

For drilling holes in bricks, you'll get the fastest results from


A masonry bit. These have a piece of tungsten carbide brazed into the tip.
A drill with hammer action.


A corded drill will usually perform better than a battery-powered drill of the same price.

An SDS drill would be the very best but purchasing one is probably overkill if you only have a few holes to drill. 

Other experts herebouts have previously pointed out that you can succeed with an ordinary electric drill and an HSS bit. I have found that to be hard work (different types of brick vary a lot in hardness) and much prefer using a masonry bit in a hammer (or "combi") drill.