Pfaff 339 Owner's Manual - Page 9

Exchanging the Sewing Foot Raise the presser bar lifter and the needle all the way and loosen the sewing foot fastening screw until you can tilt the sew ing foot slightly to the left and take it out from underneath the screw. To replace the sewing foot place its cutout side from the left onto the presser bar and move it up until it stops at the threading of the sewing foot fastening screw. Then use a screwdriver to retighten the fastening screw firmly. Correct Size Needle and Thread For selecting the right kind and size of thread and needle for various kinds of fabric, on ing results. For medium-weight linen and cotton fabrics you should start with thread No. 60 and a needle No. 80. When working very fine or very thick material first try out on a piece of remnant whether you have chosen the correct needle and thread sze. As bobbin thread you should preferably use thread which is a little softer and finer than the upper thread. For sewing woolen i- and silk fabrics you will mostly be using sewing silk where there is no difference between upper and bobbin thread. f For fashion stitches we recommend the use of mercerized upper thread or sewing silk or machine embroidery cotton, and as bobbin thread machine embroidery cotton No. 50. H H