I am specifically referring to the standard NEMA 5-15 three hole outlet that is used in North America. What are the dimensions of the holes in the outlets?
Surprisingly, I am having difficulty in finding this information on line.
Let me introduce you to the wonderful world of Google Image search:
It's a great way to find drawings and other visual information.
Here's a drawing pulled from the search results:
Dimiensions are millimeters with a comma used instead of a decimal point.
Following some image searches and regular searches I also came across the official NEMA Website
This NEMA WD 6 - Non-Locking Plugs and Receptacles - Excerpt PDF should have the information you want.