Objective: Assemble the main structural seams of your signature project on the Janome MC6650, producing a clean, durable core body before adding details or finishing.
The core is the load-bearing skeleton of your product: the panel-to-panel seams that give it shape and strength. On the MC6650 you build the core with a straight stitch (stitch #1), length set to 2.4-2.5mm for general seams, dropping to 1.8mm where seams will take stress (bag bottoms, strap anchors). Use the 1/4in or 3/8in guide line etched on the needle plate to hold your planned allowance consistently. Always backstitch 3-4 stitches at the start and end using the reverse lever, or let the machine's auto lock-stitch button secure the thread tails. Work in your planned sequence from lesson 2 so you never sew yourself into a corner. Two habits separate hobby work from sellable work: press every seam open or to one side immediately after sewing it, and grade or trim bulk at intersections where multiple seam allowances stack, so corners turn crisp rather than lumpy. Keep an even feed by letting the dual feed (if engaged) and presser foot pull the fabric; guide, don't pull. Check your seam allowance against your pattern at each checkpoint before moving on, because a 2mm drift repeated across six seams becomes a visible sizing error.
Try it: Sew the core seams of your signature project now. Set stitch #1, length 2.5mm, and line your fabric edge on the 3/8in plate guide. Sew your first two main panels right sides together, backstitching at both ends. Press the seam, then measure the finished allowance with a ruler at three points; it should read a consistent 3/8in. Join the remaining core panels in your planned order, dropping to 1.8mm on any stress seam and trimming intersection bulk to a staggered 1/8in and 1/4in. Stop when the main body holds its intended 3D shape without details attached.