On Thursday, August 1, 2013 5:58:21 AM UTC-5, Bob_Villa wrote:
The wall is ceramic tile, drywall, foam, and then 12" concrete block (I can't detect any hollow). I have a 12" long masonry bit but the total wall is something like 18 inches! Is there a way of detecting where the drill is located from the outside (after maxing the depth from the inside)? I was wondering about studfinders that can detect live wires and metal studs or a non-contact voltage detector and connecting a live wire to the bit or rod...any thoughts on this? Thanks! Bob_V

An extension holder for the bit is not that expensive, assuming you have a decent hardware store within 20 miles or so.