Why Do Bolts & Screws Become Loose – How to Stop Screws From Loosening


Screws and bolts can get loose over time due to a combination of several factors, which brings some risks. This post will present the reasons why bolts and screws get loose and how to stop them from loosening.

Why Do Bolts & Screws Become Loose?

1. Vibrations: When a machine or equipment is in use, vibrations from moving parts can cause the bolts to gradually become loose.

2. Thermal expansion and contraction: Fluctuations in temperature can cause the materials around the bolt to expand or contract, leading to a loss of tension in the bolt.

3. Material fatigue: Over time, the repeated stress on the bolt can cause it to weaken and deform, leading to a loss of tension.

4. Insufficient torque during installation: If a bolt is not tightened to the necessary torque specifications during installation, it can become loose over time.

5. Corrosion: Exposure to moisture or other corrosive substances can weaken the bolt and cause it to become loose.

6. Joint relaxation: Over time, the materials around the bolt can “settle” into their positions, causing the bolt to lose some of its initial tension.

7. Improper use: If the machine or equipment is used in a way that puts excessive stress on the bolts, it can cause them to become loose over time.


What is the risk of screw loosening?

Screw loosening can pose different risks depending on the context where it occurs. In some cases, it may cause machinery or equipment malfunction, structural instability, or failure. In medical implants, screw loosening can lead to a loss of fixation or stability, causing pain, discomfort, and potential revision surgery. Overall, it is important to monitor and address screw loosening promptly to prevent further complications.

How to Stop Screws From Loosening?

1. Tighten screws to the appropriate torque specification using a torque wrench or other suitable tool.

2. Use thread-locking compounds such as Loctite to provide a chemical seal and prevent screws from vibrating loose.

3. Employ locking mechanisms, such as lock washers or Nylon-insert nuts, to prevent screws from rotating and loosening.

4. Use adhesive bonding techniques, such as using epoxy or other suitable adhesives to secure screws and fasteners in place.

5. Consider using anti-vibration pads or dampers to reduce vibrations that can cause screws to loosen.


How often should you tighten screws?

The frequency of screw tightening depends on the specific application and the conditions under which the screws are used. In some cases, screws may need to be tightened frequently, such as in machinery subject to frequent vibration. In other cases, screws may require less frequent tightening, such as in stationary structures. As a general rule, it is advisable to inspect screws periodically and retighten them as needed. The frequency of inspection and tightening can vary widely, from daily or weekly checks to less frequent inspections, depending on the application. In some cases, it may be useful to establish a maintenance schedule that includes regular inspection and tightening of screws. The best approach is to monitor screws regularly and tighten them as needed, taking into account the specific application and conditions under which they are used. If you have any concerns about the frequency of screw tightening in your specific context, it is recommended to consult with a knowledgeable professional.


When should you stop tightening a screw?

Stop tightening a screw when it has reached the appropriate torque specification. If a screw is tightened beyond its recommended torque limit, it can cause damage to the screw, and the surrounding material, or lead to other problems such as thread stripping. It is essential to follow the manufacturer’s recommendations on torque settings or consult with a knowledgeable professional if the recommended settings are unclear. Additionally, some applications may require additional measures or techniques to ensure proper tightenings, such as using a torque wrench or other suitable tool.