How I drilled a concrete ceiling without noise with a diamond crown...

There was a need for me to drill 15 holes in the concrete ceiling. I could use a puncher for these purposes.

But I have neighbors. I did not want to make any noise, and I myself do not like noise, even if I'm drilling myself.

I decided to drill with diamond bits. I took a regular screwdriver 12V 400-1200 rpm. 1200 rpm is sufficient for the use of diamond crowns provided they cool down during operation.

It is quite clear that when you drill a hole in the floor or in the wall, the water supply for cooling does not present a problem. But how to feed water to the ceiling and carefully collect it back? Tried to drill, using a foot pump to feed water. Of course I was all wet and dirty.

I figured out how....
I took a diamond-coated tubular drill, closed the sealant opposite to the working hole and poured water inside.

I drilled one hole and spoiled the drill bit. The water evaporated.

I remembered that there is a motor oil and searched at home - I did not find it. In the fridge was olive. I filled it and started drilling.

The oil boiled and spilled out of the hole (USE GLOVES AND PROTECTIVE GLASSES!!!!) and burned my hand.

I looked at the diamonds - on the spot.
Poured the rest of the oil, cleaned the drill, filled in a new oil - he began to drill further.

And so all 15 holes

Then I decided to see if there are such drills on the Internet (maybe I'm an inventor?)
It turned out that there is. From Bosch. Expensive.

I ordered one.
As it turned out they also use olive oil.
The drill was sent by post, decided to test it.

But for some reason he spoiled it very quickly.
I decided to clean it and found a piece of metal in the hole.

Where did he come from? Marriage, or overlooked under control? I never received a reply to this question.

P.S.:
Olive oil. The boiling point for "extra virgin" is 160 ° C
The optimum temperature for maintaining the integrity of diamond spraying on the head.