NYC apartment walls
 

I just moved into a building in NYC that was built in the late 60s and I wanted to mount my 42" plasma. I drilled a few test holes after I used a stud finder and discovered the walls were about 2.5" thick. The drill bit went right through, I now have a peep hole to my bedroom. The other hole went in 1.25" and stopped. The dust looks like drywall/clay dust. The walls seem thick though, I can't hear people talking in the other room.

Any ideas what kind of walls I'm dealing with?
Should I abandon all hope of mounting my TV or anything for that matter? I was hoping to mount some shelves also.

Take a picture sounds like a heavy plaster wall.... Is it textured? Stud finders don't work on plaster or not correctly anyway
Good news is you have studs just where?

It's mostly smooth. There are several patch jobs and about a half inch of paint from multiple repaints. The stud finder I have is one of the cheaper ones.
Aren't studs 2x4s?
These walls are 2.5" thick, fairly dense. No hollow sounds when I tap on them to find the studs.

Perhaps they turned the studs sideways in none bearing walls to give more room in the appartment.

Do you have Baseboard trim and or radiator? If trim pop it out look for nail heads if u see any that's we're your studs are. They could of doubled up on the Sheetrock at some point what size screws are you using?

The screws are about 2" long wood screws, typical to a TV mounting kit. The building super is out of town so I think I'm going to have to talk to him about this.

Thanks for the tips.