When I began to learn to spin I stated to many and all that my goal was to learn to spin fingering weight. It's my favourite weight of yarn to work with. But I was met with a lot of skepticism from well-meaning friends. They all told me that once I learned to spin fine, I would find in extremely difficult, impossible was implied, to spin thicker again.
Well, I'd say, you just draft more fiber, use a heavier spindle and off you go.
Oh no! said my friends with a laugh. It's not that simple, everyone has this problem.
Mary Jane said "Laurie, when you come crying to me that you can't spin thicker yarn, I will laugh in your face."
Well, look who's laughing now.
I just decided to give it a try and got these results on my first attempt. I imagine I could get better with practice. Here's a comparison with commercial Shetland fingering weight on the right: