In first operation total length is maintained to 70mm and center is provided for supporting purpose and that is cleared in final set up.in 2nd set up 66.65mm length is maintained and 3.35mm step is maintained for next set up for supporting purpose.in threadding operation turning tool z-offset is taken to face of the part and threadding tool offset is taken to 3.35mm step and when 3.35mm is given in work offset to maintain 66.65 total length.when 3.35mm is moved in work offset  thread length also 3.35mm is move so thread length oversize part reject.