Lesson 8
What the Drill Tells You
Read the dust and the push as you drill, and know which signals mean stop.
Builds on
The drill talks
As you drill, the wall tells you what it's made of. The colour of the dust shows which material the tip is in, and the push you need, with any sudden give, shows where one layer ends and the next begins. It's like reading a core of rock a centimetre at a time.
Two limits. Dust tells you about materials, not about cables or pipes: those you checked before the bit touched the wall, as in What Lies Beneath. And if you suspect a surface contains asbestos, don't drill it to find out; have it checked first.