Power seamers can double lock as fast as 30 feet per minute (fpm) and single lock as fast as 45 fpm. Why, then, would it be necessary to use a hand seamer? There are several conditions where hand seaming is appropriate or preferred.
The most common application for hand seaming is preparing a seam for a power seamer. Power seamers must have at least 8 inches of the seam prepared to at least the first stage. (For more on this see Preparing a seam for use with the K9 Power Seamer.)
Second are short runs where using a power seamer is impractical.
The final reason to use a hand seamer is when power seaming is impossible. Power seamers are made to work on a very specific, narrow set of tolerances. In real-world applications where seaming situations are less than ideal, or working with hard to form materials, a hand seamer is often the only option. This more traditional seaming method produces a distinctive, hand-crafted look and character that is impossible to get from a power seamer.