Practical experience is usually sufficient to determine whether Commercial Quality of Drawing Quality is required for a given part.
Where experience is not adequate, the Scribed Square Test (ASTM A 568) can prove helpful. A grid of one inch squares is marked on the section representing the most severe draw. The squares are measured for percent increase in area after drawing. Experience has shown
that Commercial Quality is usually satisfactory if the increase in area is less than 25%. If more than 25%, Drawing Quality is recommendedore than 25%, Drawing Quality is recommended