Anchor bolt nut working loose

[mouk]

I have fitted a fence post to a brick wall using acnhor bolts


A bit like in the pic below. Only difference is that the thread on mine is much longer so the anchor part is within the wall and the thread goes all the way through the fence post and has a nut and washer at the front of the fence post holding it to the wall.

What you end up seeing at the front of the post is about 2cm of thread and the nut and washer.

I didn't get round to finishing the entire project so when I came back after a few months I note that the nuts (4 of them) had started to unwide and were night fixed as tight as they originally were. Any reaso nfor this?

Solutions? Put a second nut on? Glue the nut into place. At the moment I have put some fence panel paint on it i nthe hope it will act like a glue and stop the nut coming back up the thread but probably need something a bit more solid.

Untitled

• mouk
• 13 Sep 2014
• 1

 

[Burnerman]

The fixing isn't pulling out, is it?
If it isn't, a second nut will lock things up.
John

 

[mouk]

well as the nut unwinds the post starts coming loose because I think the bit inside the wall gets smaller as the nut is undone - when i tightened the nut back up it expands again and the post is ocne again held firmly. So I need to stop the nut from unwinding.

 

[EddieM]

Probably the oscillation slowly loosening it, yep either another nut, or an anti shake washer and / or threadlock.

 

[tony1851]

It could be because the post may have shrunk slightly as it dries out. Just tighten the nuts up.

 

[theprinceofdarkness]

To keep the anchor tight the nut must be tight, but the wood shrinks, so loosens it. One way would be to use a nut and washer on the thread to lock the anchor in place. The hole in the back of the post is relieved for the depth of the nut's thickness. Then refix the wood with another nut and washer, this way if the wood shrinks only its nut becomes loose, the anchor stays in place.
Frank