Initial rough sketches, where I wanted to focus on retractable guards, an ergonomic palm fit, and a flat foot or guide with a thumb or index finger press.

Then with 9 low fidelity foam prototypes, I explored the building looking for feedback. I found Carl, who fits in the 85th percentile of males by stature, and Kristina, who fits into the 21st percentile of females by stature. Using their anthropometric measurements and verbal feedback, I continued my process with models 6 and 8 (below).

A more refined (and functional) prototype using MDF and including the circular blade. The guard is manually retractable on the prototype.

A Photoshop rendering of the redesigned Fiskars rotary blade cutter. It includes a retractable guard, is right and left hand friendly, and has light finger indentations while keeping an inner width wide enough to accomodate a higher percentage of finger knuckle spans. 

A process board to show the consideration and exploration of various concepts. Fiskars is a brand that places importance on maintaining their own visual brand language or product look and feel, as well as maintaining a high ergonomic standard.