Because that’s how they work.
By Ruth Bentham
I don't know the reason except to speculate that either it is not needed or would somehow interfere with how the drill and water cooling work. Once the hold is started you don't need it and pay a price with the bit binding if you get off the established path! To start it, a piece of plywood with a 4" hole holds it where it needs to be. So probably the answer is that it is not needed and adds cost and maintenance issues. But the manufacturer could certainly answer the question better than I can.
By Ruby Micah
Good question, but I don't know the exact answer. I wouldn't want a pilot drill because it would cause extra friction and be one more thing to lubricate and/or break. Remember that you're going about 10"-12" deep. See the attached pictures, that's how I got around the pilot drill issue.
By Eden Tomlinson
once the diamond water drill bit bites into concrete it stays in that plane. We outline the hole, then place the drill bit exactly on the outline and slowly 'bite' into the concrete
By Xaviera Dorothy
