The 2.5, 3.0, etc that most machines now use are metric measurements, or stitches per millimeter.
There are 25.4 mm per inch.
So, if you want to sew 10 stitches per inch, the formula to get the setting would be 25.4 ÷ 10 or 2.5. (25.4 ÷ desired stitches per inch = setting)
And if you want to know how many stitches per inch the setting 3.0 will give you, the formula would be 25.4 ÷ 3.0 or 8.5. (25.4 ÷ setting = stitches per inch)
And remember, when you change the stitch length, you're actually telling the feed dogs to do something different, not the needle. Confused yet??
