Grey slider carries a worm drive (rotary table in practice). Pink template and yellow work are fixed to worm wheel shaft of the drive. The template contacts violet stationary pin under pressure of red spring and makes the slider move longitudinally when the blue worm is rotated by hand. Orange cutter creates a surface on the yellow work corresponding to profile of the template.
The pin and the cutter must be coaxial and their diameters must be equal if profiles of the template and the work are requested to be the same.