Thread designation in iPart

[DRoam]

I have an iPart where I need to have different thread designations for a certain NPT-type thread feature. In the iPart Author window, I've gone to the Threads tab, and brought the "NPT_Thread: Designation" property over. However, I'm having issues with whatever I choose to put as the value for the designation. When I put "G 1/8-28" as the designation (I still have no idea why I need the "G" but Inventor won't accept it otherwise), Inventor accepts it ok. Then I save the table and close it.

But then, as soon as I try and choose a different part from the table in the navigation tree on the left, Inventor brings up a warning that reads:

The values in the Active Row of the table do not match the document's current values. Do you wish to update the table before continuing?   NPT_thread: Designation : "G 1/8-28" != "5.555555555556E-02"

Where the heck did that 5.55555etc. business come from?? If I choose no, that box comes up any time I change parts or try to insert the iPart in an assembly. If I choose yes, then it changes the designation to the huge scientific number, and then when I try and edit and close the iPart table, Inventor brings up a message that says,

Detected potentially damaging errors in table.

   Thread designation not found in thread table:

"5.55555555555556E-02"

Do you wish to continue?

It seems like Inventor could just recognize "1/8-28 as a thread designation and leave it alone, but it seems to insist on changing it to this scientific number and then complain that it doesn't know what it just did. How can I resolve this? Thanks for any advise.

[Paul-Mason]

At  a guess I'd say that the "G" is designation for GENERAL FIT such as we in the European, pain in the butt, Union use a metric thread designated as M10 F = 10mm Fine