Electrical wire gages and metal gages are different standards. Most likely the gages he is referring to is SAE (society of automotive engineers) standards.

Steel, brass, etc. can be gaged in American wire or Brown & Sharp gage, Steel Wire gage, British Standard gage, Music or Piano Wire gage, Birmingham or Stub's iron gage and finally Stub's wire gage. Confusing, right? Well don't worry. It's probably in Steel Wire gage which equates to the following dimensions: Outside diamenter

16 gage= 0.0625 inches or 1/16 inch or 1.5875 mm

10 gage= 0.134 inches or 3.40 mm

Hope that helps

Rod