bathtubdrill
I am trying to install a bath shower door . I need to drill holes into my tub and I am using a Milwaukee Drill with Dewalt titanium drill bit set. I am not sure what sort of bath tub mine is (fiber glass or metal) but I am having a hard time drilling 2 pilot holes. I held the drill for 20 secs and still nothing. Do I hold it for longer? What is the correct drill bit I use?
When you look up a chart of drill sizes, you want clearance sizes. As an example, this drill chart has the drill size used to create holes that will be threaded with a tap, as well as the larger size you would use to create a hole that will clear the given threaded fastener. It actually gives two clearance sizes for that. You might want to use the larger if those two sizes for non-precision work that has more than one fastener, otherwise you could end up with alignment issues between pieces, where the holes don't line up.
Here is a wikipedia table of the same thing.
Check your Tile bit to see if you have melted the edge. normally it should feel nice and sharp against your finger. Hopefully you have a nice drill (generally battery operated may be a little on the light side).
What I do, is get a straw filled with water, or a spray bottle, and get a helper to either "pipette" or spray water onto the hole while you drill.
Second, keep the drill at slow speed - high torque, pushing hard onto the tile. You should hear it biting into the tile, As soon as you go too fast and see the tile or bit-tip going red, you have probably destroyed the bit (this is especially true for ceramic tiles)
third. as you suggested, some bits actually like it when you move the drill in an orbital fashion. I find that it cuts well on some of my bits.
So basically, if you are keeping the cut surface nice and wet (cool), and you have a sharp bit, you are doing everything right.
I have previously bought diamond bits like these with very little success. (i think you need to go for name brands here)
These are the regular tile bits which I speak of. (and I am sure the ones you describe)
Best Answer
It looks like you're starting with a pretty large bit. I like to use the smallest bit I have (don't apply too much pressure, as skinny bits break easy) and work up. You're drilling more holes overall, but each one goes a lot quicker.