Fasteners & Torque Loading, Module 7, Certify66

1. A torque figure is given as 200 lbf·in. Taking 1 lbf·in as 0.113 N·m, this is approximately:

22.6 N·m

1770 N·m

2.26 N·m

2. A torque of 45 N·m is required using a wrench 400 mm long. The force applied at the handle must be:

112.5 N

18 000 N

8.9 N

3. A torque of 60 N·m is required at the fastener. Using a 250 mm wrench with a 50 mm in-line extension, the wrench must be set to:

50 N·m

72 N·m

60 N·m

4. For a given torque, reducing the friction under the nut and threads will:

Increase the bolt preload

Decrease the bolt preload

Have no effect

5. Why are torque values specified with the threads in the stated lubrication condition?

Friction strongly affects the torque-preload relationship

To prevent corrosion only

To ease assembly only

6. The main purpose of tightening a bolt to a specified torque is to:

Produce the correct preload (clamping force)

Stretch the bolt to failure

Seal the joint against fluid

Fasteners & Torque Loading