SMALL LETTERING
What's the secret?
 

Smallest thread (top is 40 weight, bottom is 60 weight), smallest tension, smallest hoop, smallest needle, smallest stretch in bobbin (I use cotton bobbins on small lettering for less stretch) equals best small lettering and smallest amount of headaches!.

 It is only 4" wide uppercase is 3.9mm tall and lowercase is 2.75mm

Thanks to Carl Clark of Mid-Coast Designs for the sample and picture.