drilling through a concrete wall

[zappy]

How do you avoid a blow out on the other side? Or is is unavoidable? Thank you for your help.

 

[iwire]

Drill a pilot bit through and then drill in from both sides with the final size you need.

 

[chris kennedy]

Drill a pilot bit through and then drill in from both sides with the final size you need.

Childs play.

 

[M4gery]

Drill a pilot bit through and then drill in from both sides with the final size you need.

That's it.

It's also cheaper this way because you only need 1 real long bit, preferably a 3/8" to use as a "Feeler Bit". For the final hole size you only need the bit to be as long as half the width of the wall. When going into larger sized bits, this can save considerable amounts of money.