SINGER W815 - Manual (Page 24)

27. CAUSE OF COMMON DIFFICULTIES
2. Upper thread tension too tight
BREAKING OF THE UPPER THREAD;
1. Incorrect threading
3. Faulty needle or needle set incorrectly
4. Needle brushing against presser foot or other attachments
5. Needle eye too small for thread used 6. Starting the machine suddenly or with a jerk
7. Starting the machine with the take up lever at its lowest position
BREAKING OF THE LOWER THREAD:
1. Incorrect threading of the bobbin case 2. Lower thread tension too tight
3. Bobbin being wound too fully or too loose
4. Rough edge of hole in needle plate caused by improper needle action
BREAKING OF THE NEEDLE:
1. Pulling the fabric while machine is running, thus causing, the needle to strike the needle plate
2. Using bent needle
SKIPPING STITCHES:
1. Using bent or blunt needles 2. Needle inserted incorrectly
3. Needle threaded incorrectly 4 , Using wrong size needle
5. Pressure on presser foot insufficient, especially when sewing heavy material
UNEVEN STITCHES:
1. Presser foot not resting evenly on material
3. Using too short a stitch
5. Using too fine a needle with to coarse a thread
6. Thread out of tension or check spring
Feed dog not being high enough
Pulling the cloth while the machine is running