Hi Gotta know thanks for the info , when you say its useless for leather you mean heavy leather? my intentions were to use it for french seams in auto upholstery( meaning Vinyl and auto leather ) the other question i have since you own one is what is the thickest thread you can run on it being 138 bonded the max or ? i don't plan on using nylon thread ,but bonded Poly thread holds up better in the sun,