Should you use CSK screws on metal applications?

A question we are often asked relates to countersunk screws (CSK screws) and whether they should be used on metal applications. Unfortunately, the answer isn’t straightforward, as it’s both yes and no.  

However, we can explain and that’s what we’re going to try and do in this article. Here, we will discuss both sides of the coin and hopefully, that can help you.  

We also have a video for you, which explains the reasons for not using CSK screws on metal applications. You can watch that below.  

What are the reasons for not using CSK screws on metal applications?  

It is generally advised not to use CSK screws on steel-to-steel fixings. This is because whenever a CSK screw comes into contact with metal, all of the pressure is where the screw head comes into contact with the steel plate.  

This can cause the screw to malfunction, which is less than ideal. As such, hexhead screws are a much better bet as they stop the fixing from breaking, while also keeping the material flat.  

In addition, a CSK screw can actually distort the material it is being used on. Because of the nature of CSK screws, they can bend the material – especially if it’s thin metal – out of shape.  

This won’t happen with a hexhead screw, which will instead make sure that the material remains flat. As such, it’s advised not to use CSK screws with metal applications.  

And what are the reasons for using CSK screws on metal applications? 

However, that doesn’t mean you can’t full stop. There is a way around the above, which is actually a very simple solution.  

If you countersink the corresponding hole, which will allow it to accept the screw head instead, then you’ll be able to use CSK screws on metal applications.  

This is because by countersinking the corresponding hole, the load will be spread evenly across the CSK screws, instead of all the force being on one small CSK screw.  

If all the force is on one small CSk screw, a failure is almost certain. As such, use a hexhead screw or countersink the corresponding hole to use CSK screws.  

Finding a solution 

As we stated earlier in the article, it’s not just as simple as saying yes or no, but hopefully with the explanation above, you’ll have some clarity around the situation.  

If you would like to speak to Multifix about CSK screws, then please feel free to do so. You can get in touch with us by following this link.