For final operation jaws all milled sharp and that jaws are bored after boring jaws all put one teeth outside becouse to enter that 6.3mm dia in to the jaws by doing this jaws play will came and part easily enter in to the jaws after boring part clamped in the jaws using stoper part is first clamped in the jaws and then call the stoper and butt the part to that stoper and clamp the jaws.
when clamping time part kept cross and only 2 jaws are holding that time od dig mark will occur. 