Turn the block of orange and yellow gears to clamp brown work.
Two grey pads center the work along its longitudinal direction.
Condition for centering:
R1/R3 = R2/R4
(angle speeds of blue and green gears are equal)
Relation of gear pitch radia:
R4 = R1 + R2 + R3
R1, R2, R3 and R4 are pitch radius of the orange, yellow, blue and green gear respectively.