AFCO Steel Swaged Tube 7/8 Inch O.D. 5/8-18 Threaded - 36174AFCO swaged steel tubes are formed using . 095" wall DOM material. This tubing is placed in a swaging machine that forms the reduced end size using a series of hammer to die blows. The finished product has reduced ends and the wall thickness stays within + . 001". No stretching or crimping is used to produce an AFCO swaged tube. You can't buy a better built tube for strength and weight savings. Consistent wall thickness allows better thread engagement