Cast Iron Piston Ring, 6.00 Inch OD, 0.311 Inch Width, 0.20 Inch Wall Thickness

For the groove depth, it needs to be at least 0.015 inches deeper than the maximum radial wall thickness of the ring, with a tolerance of positive 0.003 and negative zero inches. That clearance keeps the ring from bottoming out when it compresses down to working diameter. On the width side, the groove has to be at least 0.001 inches wider than the maximum ring width, same tolerance range. Both of those minimums are there so the ring can move and seat the way it needs to without binding up in the groove.