This jig is for drilling a hole on pink work.
The work is located thanks to a V-block and red stopper. The work is clamped by blue plate having brown drill bushing.
The orange gear shaft has two cones that are located in cone holes of the base. The cone angle is around 11 deg.
The shaft can move axially within small range.
Orange crank makes the plate go up and down via 45 deg. helical gear rack drive. The gear does not contact violet cyliinder.
Turn the crank counterclockwise, the plate comes into contact with the work. Turn it further for clamping work. Axial gear force pulls orange gear shaft to the right to lock the shaft by action of the left cone.
Turn the crank clockwise, axial gear force pushes orange gear shaft to the left to unlock the shaft, the plate goes up.
The red screw stops the plate at its highest position. Turn further the crank for locking the plate by action of the right cone (in brown).