Type GDX Bushings are made to the same high standards as Acme’s other Gun Drill Bushings. The I.D. is ground concentric to the O.D. within .0002 T.I.R. and the face is also square to the I.D. within .0002″ T.I.R. The head is undercut and ground square to the O.D. The O.D. of length “D” is left unground. GDX Bushings are made from tool steel and thru-hardened to 61-65 RC. Special sizes and materials are available upon request.