What is safety distance of 2nd hole when 1st hole drilled wrong. Engineering advise required.

[novetan]

I DIY, drilled and insert an expansion bolt (m6) into the concrete ceiling to hang a 6 kg chandelier. The manual recommended M6 bolt. I accidentally drilled a much bigger dia hole and the bolt keep turning render it not effective. Neither can I take it out. I’d hv to grind off. Now I hv to drill another hole which this time I will drill it same dia as the bolt. I cannot afford to shift the chandelier too off center. I believed the new hole can’t be too close to the 1st hole.

Is there a min distance for the 2nd hole away fr the 1st hole. Is 1” away too close? Any engineer here care to advise?

 

[Steven-iphone]

Is it possible to fill the void around the bolt with epoxy to stabilize it

 

[novetan]

Is it possible to fill the void around the bolt with epoxy to stabilize it

The bolt not able to removed because it is an expansion bolt

 

[Macky-Mac]

maybe the info at this site will help;

Rule: Concrete fasteners should not be set closer than 10-anchor diameters from each other.

link

 

[PinkyMacGodess]

But if the bolt won't come out, it sounds like it's working?

You might be able to tap the end of the bolt, freeing it from the wedges, and slowly wheedle it out. You might need to tap it like that and take your time extracting it. Those bolts are a PITA, and I've gotten a few stuck in the past. (NEVER 'test fit' an expansion bolt. Just don't) Depending on the bolt, you might be able to hook a drill to it, and if it will turn, just try to 'burn it out', but if it won't turn, or loosen, either live with it, or chip it out and cast a j-bolt in place: Use expansion concrete, and mix it slightly dry, and pack it in, and then jam the bolt in, and then pack more around and smooth. Keep smoothing it every few minutes, and it will eventually start to setup. Once it feels set, leave it for a day or three, and it should be good. This depends on the concrete, the thickness, and your luck/patience. It it's thin enough, and the top isn't exterior, you could go through the slab, and bolt from the top. Good luck...

I do remember seeing an 'extractor' for wedge/expansion bolts. Never tried to use one, but some claim they work. Another idea, depending how deep the hole is, you could try cementing it in place, if you can get some in, or use an epoxy for bolts and literally glue it in place. It's done all the time now. The glue is in a caulk tube, and has a special mixing end that mixes the two parts of the epoxy. Follow the instructions, and make sure the bolt is straight. Again, good luck...

 

[novetan]

Tks Macky, Pinky.

I managed to grind off the protruding threads. I will follow the 10-anchor dia rule for the new hole. That sound reasonable to me.