What is the recommended torque value for a thin plain and castellated steel hex nut used with a bolt in the shear loading average range of a size and thread pitch of 3/8-24?

What is the recommended torque value for a thin plain and castellated steel hex nut used with a bolt in the shear loading average range of a size and thread pitch of 3/8-24?

• A. 60-70 in-lbs
• B. 95-110 in-lbs
• C. 80-90 in-lbs
• D. 120-140 in-lbs

Answer: (B)

When tightening a fastener, you want enough preload to resist loosening in shear without over-stressing threads or the nut. For a 3/8-24 bolt (a fine thread) used with a thin plain or castellated steel hex nut in average shear loading, the torque must be high enough to develop proper clamping, but not so high as to strip threads or deform the thin nut. The mid-range value of about 95 to 110 inch-pounds provides that balance: it achieves the necessary preload for this size and thread pitch, while avoiding the risk of over-tightening. Values lower than this would under-tighten and could fail to prevent loosening; values higher could over-torque and damage the threads or the nut. If threads are lubricated, reduce the torque accordingly.

When tightening a fastener, you want enough preload to resist loosening in shear without over-stressing threads or the nut. For a 3/8-24 bolt (a fine thread) used with a thin plain or castellated steel hex nut in average shear loading, the torque must be high enough to develop proper clamping, but not so high as to strip threads or deform the thin nut. The mid-range value of about 95 to 110 inch-pounds provides that balance: it achieves the necessary preload for this size and thread pitch, while avoiding the risk of over-tightening. Values lower than this would under-tighten and could fail to prevent loosening; values higher could over-torque and damage the threads or the nut. If threads are lubricated, reduce the torque accordingly.