Avbruten skruv i betongvägg – hur får jag bort den?

[AZ.]

I managed to tighten a screw a bit too hard so that the actual screw head broke off (see attached images below). Now the rest of the screw is stuck in a concrete wall (in a Fischer plug).

The problem is that I'm going to put up a String shelf, and it won't look very nice to just drill a new hole next to it because the old hole will be visible. Therefore, I would like to remove the broken screw and preferably be able to use the same hole again.

I've already tried a simpler method: I took another, smaller screw and screwed it into the plastic part of the plug to then try and pull out the whole plug. Unfortunately, it didn't work well at all.

Therefore, I've started looking at screw extractors and understand that there are two common types:

1. Regular spiral extractor:
   First, you drill a hole in the broken screw and then screw in the extractor, which grips the screw and hopefully unscrews it.
   
   
2. Left-handed drill + extractor:
   You start with a left-handed HSS drill that runs in reverse. In the best case, the screw starts to unscrew itself already then; otherwise, you've made a hole for the extractor.
   
   

I've also received the tip to ignore extractors and instead use an HSS drill and just drill straight through the entire screw until it's gone.

What is really the best and smartest way to start in my case? The screw is quite thin (about 3 mm in diameter) and is stuck in a concrete wall. I would like to avoid damaging the hole as I want to be able to use the same spot again.

I'd love to receive tips and experiences!

 

[Dkvist]

I managed to tighten a screw a bit too hard so the screw head itself broke off (see attached images). Now the rest of the screw is stuck in a concrete wall (in a Fischer plug).

The problem is that I'm supposed to install a String shelf, and it wouldn’t look particularly nice to just drill a new hole next to it, as the old hole will be visible. Therefore, I’d like to remove the broken screw and preferably be able to use the same hole again.

I've already tried a simpler method: I took another, smaller screw and screwed it into the plastic part of the plug to then try to pull out the entire plug. Unfortunately, it didn’t go well at all.

I’ve therefore started looking into screw extractors and understand that there are two common types:

1. Standard spiral extractor:
   First, you drill a hole into the broken screw and then screw in the extractor which grips onto the screw and hopefully unscrews it.
   [image]
   
2. Left-handed drill + extractor:
   You start with a left-handed HSS drill that runs in reverse. Ideally, the screw starts to unscrew itself right then; otherwise, you've made a hole for the extractor.
   
   [image]

I've also been advised to skip the extractor and instead use an HSS drill and just drill through the entire screw until it's gone.

What is really the best and smartest way to start in my case? The screw is quite thin (about 3 mm in diameter) and is in a concrete wall. I’d like to avoid damaging the hole as I want to be able to use the same spot again.

Happy to receive tips and experiences!

I experienced the exact same situation when mounting the shelf. The solution was to move the shelf one centimeter to either side and fill and paint the screw holes that no longer suited. I left the screw in the hole.

 

[Alfredo]

I think you'll have trouble with some kind of extractor on such a weak screw. I would try to drill out the plug with a drill bit, maybe 2 mm, repeatedly in the plug between the screw and the concrete.

If that doesn't work, I would simply drill one or more holes next to it and then fill everything in with some house repair compound or something similar and start over.

 

[AZ.]

Thank you for taking the time to respond, Dkvist and Alfredo! I really appreciate your replies.

 

[Alfredo]

Thank you for taking the time to reply, Dkvist and Alfredo! I really appreciate your responses.

Glad to hear. Don't forget to let us know how it went.

 

[Cruzze]

You could try cutting a notch into the screw with a small diamond grinding wheel like a Dremel (which can be attached to a drill) and then try to loosen it with a regular flat-head screwdriver.