I am trying to build a representation of a thermowell to determine its natural frequency. I plan to start at one end at .75" diameter and progress over a series of steps to the 0.5" diameter at the end.

However, when I enter 0.75" into the diameter, it automatically converts it to 1.05", which is the true OD of a 3/4" nominal pipe. Putting in .74, .73, and .72 appear to generate some kind of rounding which again makes me end up with 1.05".

How do I force the box to accept the number as an actual OD instead of a nominal one? I've been searching through the documentation, but the only mention is that the diameter is converted to actual diameter based on the selected database in setup. Going to setup, I find that I cannot specify "none" for the database.