I am working on repairing the upstairs ceiling to our 1930"s home and have run into an unusual problem. The wood making up the lathe, strapping, and joists of our old plaster ceiling is resisting all attempts to screw or drill through it. New bits haven't had any effect on it. I can get an 1/8" into the wood and then get stopped. Pecking with the drill hasn't worked either and switcing to different wood bits hasn't helped.

The plaster walls are no trouble at all so it's a bit perplexing. Has anyone encountered this or have advice on how to work through it. I'd rather not have to tear out the entire ceiling for simple plaster repairs.