Most Carhart jackets are sold to industrial/construction industies and are
heavy duty jackets that get dirty a lot. Satin stich will certainly come
loose or the threads break with the type of work that they do. All it takes
is something sharp and your lettering has come apart. I would use a fill
stich. It will take longer to sew out but your lettering will last much
longer than a satin stitch. Pull your letters close enough to each other and
use closest point so you won't have to do any trimming. (I do this on all
lettering.) This will save some time after the job is complete.
Lisa Wolf Embroidery Wolfemb@xxxxxxxx Lisa and Don Ridley