I've tried several drill bits/chisels. This is the best I've found. I admire the countersink part, they seem to work forever in difficult materials. Drills dull quickly in cement board, but large 3.2mm drills are available and inexpensive. Just replace as needed. I wish they came in larger sizes!
Bit and socket set BOSCH Promoline (2.607.017.322), 26 pcs.
24 Review
Tool set Stels Tool set, 1/2", 1/4", CrV, plastic case 94 pcs, Stels, 94 pcs, black
45 Review
𧱠Bosch 2607017164 Piece Setter Masonry: Advanced Tools for Precision Masonry Work
20 Review
Tool set Ombra OMT94S12, 94 pcs, brown
27 Review