ANSI B18.2.1 Bolt Fastening Steps

   We must insert the ANSI B18.2.1 bolts into the holes freely, and do not force the taps. The washer of ANSI B18.2.1 bolt is mounted on one side of the nut. The chamfered side of the washer hole should be in contact with the nut and cannot be reversed. If it is found that the ANSI B18.2.1 bolts are not free to penetrate, at this time, the gas cutting cannot be used to ream the holes, but the reamer can be used to re win the holes. In the repair of the hole, it is necessary to use the layer to close, in order to prevent the iron pin from entering the gap of the plate. A grinder can be used after the reaming to clear the burrs on the edge of the hole and to remove the iron filings.     The tightening of the ANSI B18.2.1 bolts is initially started. Then do the final screwing. In other words, it must be tightened twice. It is sufficient to tighten to 60% to 80% of the standard axial force of ANSI B18.2.1 bolts when making the initial tightening. The torque value of the initial tightening is not less than 30% of the final tightening torque value. The secondary tightening is the final tightening. When the final tightening, the torsion shear type high-strength bolt should be screwed off the plum blossom chuck. In order to make all the bolts in the torsional shear type ANSI B18.2.1 bolt group evenly stressed, the initial and final tightening should be carried out in a certain order.