What is the best way to check the torque value on a bolt?
There are three basic methods for the checking of torques applied to bolts after their installation; namely, taking the reading on a torque gauge when:1. The socket begins to move away from the tightened position in the tightening direction. This method is frequently referred to as the “crack-on” method.2. The socket begins to move away from the tightened position in the un- tightening direction. This method is frequently referred to as the “crack-off” method.3. The fastener is re-tightened up to a marked position. With the “marked fastener” method the socket approaches a marked position in the tightening direction. Clear marks are first scribed on the socket and onto the joint surface which will remain stationary when the nut is rotated. (Avoid scribing on washers since these can turn with the nut.) The nut is backed off by about 30 degrees, followed by re-tightening so that the scribed lines coincide.For methods 1. and 2.
There are three basic methods for the checking of torques applied to bolts after their installation; namely, taking the reading on a torque gauge when: 1. The socket begins to move away from the tightened position in the tightening direction. This method is frequently referred to as the “crack-on” method. 2. The socket begins to move away from the tightened position in the un- tightening direction. This method is frequently referred to as the “crack-off” method. 3. The fastener is re-tightened up to a marked position. With the “marked fastener” method the socket approaches a marked position in the tightening direction. Clear marks are first scribed on the socket and onto the joint surface which will remain stationary when the nut is rotated. (Avoid scribing on washers since these can turn with the nut.) The nut is backed off by about 30 degrees, followed by re-tightening so that the scribed lines coincide. For methods 1. and 2. the breakloose torque is normally slightly higher than the
