Facit TK Mechanical Calculator Demo (1936)

This is a demo of the Facit TK mechanical calculator. This Swedish pinwheel calculator was introduced in 1936 and got famous for introducing number entry with a numerical keypad instead of levers. Despite its simplicity, it has numerous clever features, a few demonstrated here. A legacy of the Facit calculator to this day is the digital numerical keypad with the zero at the bottom. See companion video of the mechanism inside here:    • Inside the Facit TK Mechanical Calculator