Objective: Sew a complete small lined potholder, combining machine setup skills from earlier lessons to produce a finished, sellable item.
A potholder is the ideal first project because it uses only straight seams, teaches seam allowance control, and results in a usable product. You'll work with three layers: two outer fabric squares (right sides facing in) and a layer of heat-resistant cotton batting. Set the MC6650 to a straight stitch (stitch 1), stitch length around 2.5mm, and keep the needle in center position. Use a consistent 1/4 inch (6mm) seam allowance by lining your fabric edge up with the guide mark on the needle plate. Always backstitch (press the reverse button on the front panel) three stitches at the start and end of each seam to lock the thread so it won't unravel during use or washing. Sew around all four sides but leave a 3-inch gap on one side so you can turn the piece right-side out. After turning, press flat and topstitch close to the edge to close the gap and give a professional finish. The MC6650's needle up/down button is useful for pivoting at corners: stop with the needle down, lift the presser foot, rotate the fabric 90 degrees, lower the foot, and continue.
Example: Cut two 8-inch squares of quilting cotton and one 8-inch square of insulated batting. Stack: batting on bottom, then one cotton square right-side up, then the second cotton square right-side down (so the two cottons face each other). Pin. Starting on one side, backstitch, then sew a 1/4-inch seam. At each corner, needle down, pivot, continue. On the final side, stop 3 inches from where you started, backstitch, and cut the thread. Trim the four corners diagonally (don't cut the stitches). Turn right-side out through the gap, push corners out with a chopstick, press. Topstitch 1/8 inch from the edge all the way around, closing the gap as you pass it. You now have a finished potholder.
Try it: Make one potholder following the example. Measure your seam allowance at three points with a ruler—each should be 1/4 inch (6mm). Confirm you backstitched at the start and end of every seam, and that your topstitching closed the turning gap. Set it on a flat surface and check that all four corners lie flat and square.