This specification covers seamless and welded steel@ welded open-hearth iron@ and welded wrought-iron casing and tubing@ seamless steel drill pipe@ also (as tentative) seamless and electric-welded steel liners. It includes regular and internal-upset casing with short and long threads@ plain-end liners@ non-upset and external-upset tubing@ and internal-upset and external-upset drill pipe-in the sizes and wall thicknesses applicable to the various grades of pipe as shown in the standard lists (Tables 1 through 4)@ and in the dimensional tables (Tables 9 through 15). Dimensional requirements on threads and gages@ and stipulations on gaging practice also are covered@ as well as requirements for couplings and thread protectors. Nothing contained in this specification is to be construed as granting any right@ by implication or otherwise@ for manufacture@ sale@ or use in connection with any method@ apparatus@ or product covered by letters patent@ nor as insuring anyone against liability for infringement of letters patent.