The yellow work is clamped to the grey conrod of a parallelogram mechanism and has round translational motion.

Radius of inner cylindrical surface to be created is Rw (orange circle). Locus of center of the orange circle is the green circle of radius Rc (radius to be set of the green cranks by violet screws).

The red tool radius is Rt.

Rw = Rc + Rt

Tool setting position: as start position of the simulation video.

The jig is used for large inner cylindrical surfaces on bulky works.