Different Kinds of Fans
This is a short informative set of paragraphs to help you more fully understand what will be discussed in future chapters.
If you ever watch movies you're familiar with scenes where the sweaty, hot actors try and cool themselves in front of electric fans. Ever watch the fans closely? They either are rotary or oscillating, meaning they spin side to side (oscillating) or they spin in a complete circle (rotary).
Sewing machines have the same either/or feature. The hook (that's the thing that you put your bobbin into) spins round and round or they spin halfway, change direction and spin the other way back to where they began. turn the handwheel on your machine and watch how your machine' s hook works. Nowadays most machines are rotary.
A rotary hook allows for wider stitch formation thereby giving the machine the ability to make different kinds of decorative designs.
Unless the manufacturer goes to different lengths in terms of preciseness in the manufacturing process, the oscillating hook can produce a better tension but they also produce more skipped stitches. On another page shortly, we'll get into the definition of timing a machine properly and explaining what is involved in that area. The kind of fan the machine has weighs heavily in solving problems any sewing machine has.
