Why does my rotary switch not have a common pin?

Occasionally when you purchase a rotary switch you may be caught off guard to realize the there is no common contact. Some switches are constructed with a shorting contact instead, and an explanation of how they function is below.
image
As you can see in the image above, taken from the datasheet C&K F series datasheet, this particular switch has 3 positions. Position 1 will connect contacts 8 and 1, via the blue shorting contact. Turning the switch forces the shorting contact between contacts 1 and 2, then 2 and 3.

This construction of switch can prove slightly more difficult to wire, so be sure to double check on the datasheet before purchasing,and keep an eye out for “No Common Pin” located under the features filter of our rotary switch selection.
image

See also:
Rotary Switch Identification