Objective: Sew the primary load-bearing seams of your capstone item so the body holds its intended shape, pressing and checking as you go to meet resale-quality standards.
The 'core' is the skeleton of your product: the seams that join the main panels and give the item its three-dimensional form, before any hems, closures, or trims. On the Janome MC6650, use a straight stitch (stitch #1) at length 2.4–2.8mm for most woven cottons, and reduce to 2.0mm at high-stress points like underarms or bag corners. Keep a consistent seam allowance by lining your fabric edge against the 3/8" or 5/8" guide on the needle plate—consistency here is what separates a product that looks handmade-good from handmade-sloppy. Always backstitch 3–4 stitches at the start and end of a seam (hold the reverse button) so nothing unravels during wear. The non-negotiable habit at this stage is press-as-you-go: after each seam, set it with a hot iron (seam closed, flat) to meld the stitches, then press it open or to one side as your pattern directs. Pressing a seam after it's crossed by another seam is nearly impossible, so you press before you sew across. Sew in a logical order—join small subassemblies first (e.g., a pocket to a panel), then join the larger panels together—so you're never fighting fabric bulk through the machine's throat. Use the MC6650's needle-down setting to pivot cleanly at corners and the knee lifter to keep both hands on the fabric.
Example: Say your capstone is a lined zip pouch. You take the two outer panels, place them right sides together, and sew the two sides and bottom at a 3/8" seam, stitch length 2.4mm, backstitching at both ends. You stop at each corner with the needle down, lift the presser foot with the knee lifter, pivot 90°, and continue. You then press each seam open over the point of the iron. To box the corners, you pinch each bottom corner into a triangle, mark a 1.5" line, drop to length 2.0mm, and sew across—this transforms a flat pouch into a dimensional one. That assembled outer shell, pressed and square, is your completed core, ready for the lining and zipper in the next lesson.
Try it: Sew the main structural seams of your own capstone item now. Set the MC6650 to straight stitch at 2.4mm, verify your seam allowance against the needle-plate guide, and backstitch every seam. After each seam, press it (set then open or to the side) before sewing any seam that crosses it. Join subassemblies before main panels. When finished, you should have a pressed, three-dimensional core with no hems or closures yet attached. Lay it flat and photograph it for your project record.