Millwright Level 1 Practice Exam

Can hex set screws be doubled up?

1. Yes

2. No

3. Only under certain conditions

4. Depends on the application

The correct answer is: Yes

Hex set screws can indeed be doubled up to enhance holding power and provide greater resistance against loosening over time. When two set screws are used in conjunction on the same thread, they can share the load, which can improve the overall tension and stability of the connection. This technique is often employed in applications where vibration or dynamic loads may cause a single screw to loosen, offering a more secure fastening solution. Using two set screws can create a preload effect, where the combined force of both screws contributes to a stronger attachment. However, it's essential to ensure that both screws are of the appropriate size and material for the application to avoid issues like stripping or galling. In specific situations, such as when space is limited or where proper alignment cannot be achieved, doubling up may not be the best choice. Thus, although it is possible and sometimes recommended, the effectiveness of doubling hex set screws ultimately depends on the particular application and conditions they are subjected to.