If you have, or had, special names for your grandparents (Nana, Bubbe, Gam-gam, etc.), do you use that name when referencing your grandparents to others?

For example, which of these would you say to a casual friend?:
1) "My Nana knit this scarf for me."
or
2) "My grandma/grandmother knit this scarf for me."

And if you do/did have special names for your grandparents, what are they?