Wondering if a specific tool exists - grab thread and turn bolt

[Stuart91]

I've had an interesting job land in my lap. 

A venue we deal with has a bunch of ceiling brackets that need removed.

They're into a fairly inconsistent concrete slab above, and the fixings are through-bolt style rawlbolts, like this:

 

The problem is that the concrete is loose enough that the fixing spins freely, but the nut won't loosen at all. I had a shot at one and the only way I could ease it off was by holding the protruding thread with a pair of pliers and using a spanner. That's fiddly and time-consuming, but there's not enough clear space around the bolt heads to do much else. I can't get an angle grinder into it, for instance. 

There's a couple of dozen of these fixings need to come out, and I'm dreading the task. I'm wondering if there's some sort of specialised tool that would help with this? I'm guessing it can't be that uncommon a problem but I can't even think of what terms to start googling. 

 

[boatman]

A multitool with a metal cutting blade should do the job.

https://www.toolstation.com/dewalt-dcs356-18v-xr-multi-tool-3-speed/p98472

https://www.toolstation.com/bosch-expert-starlock-carbide-metal-plunge-cut-multi-tool-blade/p98073

Edited February 16, 2023 by boatman
Additional details.

[Dave m]

I have seen it done by stacking washers over the stud, then using the nut to jack out the stud as far as possible.

use a cut off disc on a grinder/ dremel. And hammer the remaining stud back in.

If you are lucky it falls out the back into the hole

or use the above but rather than hammering, use a reverse drill to spin the remaining stud back inwards.

 

just had an idea.

if you can damage the ceiling, a bit, use a studding extender nut welded to a metre long handle and “stir”  the handle to enlarge the bore of the hole?

Edited February 16, 2023 by Dave m

[Stuart91]

31 minutes ago, Dave m said:

if you can damage the ceiling, a bit, use a studding extender nut welded to a metre long handle and “stir”  the handle to enlarge the bore of the hole?

I like this idea - could be a plan. 

 

 

The complicating factor with any cut-off tools is that the fixings are recessed from the ceiling surface - we've got lathe-and-plaster over the concrete slab. This has been cut away to give space for the brackets, but only just. There's no room round about to get a blade in without savaging the surrounding material. 

[kerry davies]

I would need to see it to make a sensible suggestion but ....... Is there enough thread protruding to allow another nut to be screwed on? If there is one of my favourite bash-it-n-bodge-it tools is a slide hammer or bearing puller and just use BF&I on them.

[sunray]

Have you tried many to see if they spin?

I have had pretty much an identical situation where the fixings were made in a recess.

We added a stud extender nut to create a 'slide hammer' luckily several taps 'out' was enough to jam the fixing in the hole which was then enough to undo the nut.

 

However can you not use a grinder to cut off at sub ceiling level or is the nut still securing the bracket? If so does adding weight to bracket jam the fixing?

 

Another thought is extend the stud as above but but use a power drill to turn the fixing while pulling it down, hopefully it my grind a bigger hole.

[Stuart91]

1 minute ago, sunray said:

If so does adding weight to bracket jam the fixing?

That might work. 

They are standard saddle brackets so we have two fixings per bracket, but could probably pull down at an angle to apply some force behind the nut. 

[Malcolm Gordon]

Cut a screwdriver slot in the end of the thread, to hold it steady whilst using the spanner?

[indyld]

I think similar method has been suggested, but my first thought was to fabricate a puller using a bit of unistrut and whatever studs, plates, nuts and washers needed to put force on the whole thing. Maybe the whole thing will pull out, or at least jam the fixing enough to unscrew the original stud. 

Presumably, the area needs making good anyway so a bit of chipping away around the fixing might help the puller. 

[sunray]

16 hours ago, Stuart91 said:

That might work. 

They are standard saddle brackets so we have two fixings per bracket, but could probably pull down at an angle to apply some force behind the nut. 

Ah perfect.

in that case a long m12 bolt (or studding) through the middle hole with several washers and a nut and grease inside.

Use as a screw jack against the concrete slab.

Try to start both nuts before losing the ability of the jack.

[dje]

I know that this isn't specifically what's being asked of you but I'll say it anyway. I do some inspections work and often we condemn rawl bolts or chem fix anchors - both leaving the stud sticking out of the wall. When we condemn them, rather than removing the fixing, we tend to chop the ends off with either an oscillating multi-tool or a 4-inch grinder (depending on how quick you need to be and how much aesthetic damage you're allowed to do to the surrounding wall/ceiling).

This does leave a little piece of steel in the wall but if done properly it should be flush - so comes with the benefit of not leaving a hole. 

The problem with pulling out expansion fittings from concrete is that depending on the condition of the concrete, you may find that you pull out more concrete than you wished for and you end up leaving big cavities all over the wall that your client didn't ask for. These can be costly to fill in and the filler will never match the old concrete (short of giving it to a scenic artist to sort out).

[TomHoward]

It’s definitely the fixing spinning freely and not the studding turning with the bolt attached out of the taper bolt at the back of the fixing? If that were the case it should spin right out a few turns later. (It may leave some semi-loose steel fastening in the hole to fall out later on audience though depending on location) 

Edited February 17, 2023 by TomHoward

[Stuart91]

All good points, thanks everyone. 

I've explained some of the challenges to the client who is OK with me quoting a day rate and saying "it'll take as long as it takes" rather than a solid figure. 

We'll probably go armed with a variety of options to encourage the nuts to loosen. 

The plan is that the ceiling will be made good after we've done our bit - the objective is to hide any evidence of their having been fixings there. 

On 2/17/2023 at 7:59 PM, dje said:

rather than removing the fixing, we tend to chop the ends off with either an oscillating multi-tool or a 4-inch grinder (depending on how quick you need to be and how much aesthetic damage you're allowed to do to the surrounding wall/ceiling).

This would work OK - in fact I won't even need to cut the studs down, as long as I can get the nuts off and the saddle brackets removed. The studs stop well short of the ceiling so the patches will conceal them quite nicely. 

[sunray]

Silly suggestion... Hammer and chisel to split the nuts?

[alistermorton]

Or even a proper nut splitter?