Objective: Learn and correctly use the essential sewing vocabulary and machine-part names that every later lesson and project instruction in this course will assume you know.
Before you can follow a project, you need a shared language. On the Janome MC6650, the presser foot holds fabric flat against the feed dogs (the metal teeth that pull fabric through). The needle moves up and down to form stitches with the bobbin thread (lower) and the needle/top thread. The throat plate under the needle has engraved seam allowance guide lines. Key concepts: Seam allowance is the distance between the fabric's raw edge and your stitching line, most commonly 1/4 inch for quilting and 5/8 inch for garments. Stitch length is how far the fabric advances per stitch (measured in mm; 2.4-2.5mm is a standard straight stitch; longer basting stitches are 4-5mm). Stitch width applies to zig-zag and decorative stitches and controls side-to-side swing. Thread tension balances how tightly the top and bottom threads pull against each other; balanced tension means the threads lock in the middle of the fabric layers, not on top or underneath. Backstitch (reverse) locks stitches at the start and end so seams don't unravel. Right side is the finished/public side of fabric; wrong side faces inward. Understanding these terms turns confusing instructions like 'sew a 5/8" seam at 2.5mm, backstitch at both ends' into clear actions.
Example: Instruction reads: 'With right sides together, sew a 1/4" seam, stitch length 2.5mm.' Translation: place the two fabric pieces so their finished sides face each other; line the raw edge up with the 1/4" line on the throat plate; set the MC6650's stitch length display to 2.5; sew, keeping the edge on that line the whole way. The threads should lock neatly between the layers, showing even dots top and bottom.
Try it: Point to or write down the location of these six items on your MC6650: presser foot, feed dogs, bobbin, throat plate seam guides, reverse/backstitch button, and the stitch length control. Then write a one-sentence plain-English definition for each of these four terms without looking back: seam allowance, stitch length, tension, right side of fabric.