I've been using M12 thrubolt anchors like these...
http://tinyurl.com/4lkgu
.... to attach a joist parallel to the wall, but they haven't 'worked' at
all well, in that one just pulled out of the wall when I tightened the
bolt; and when I removed the joist to try to rectify this, another one
failed as well when I replaced the bolt and retightened it. (The
remaining two are well anchored and work fine).

Looking at the actual fittings, they seem to me to fundamentally flawed:
they have no sleeve, so that as you tighten the bolt, the anchor moves
outwards, and relies on achieving enough friction with the wall of the
hole to enable the conical 'plug' to engage with the anchor and splay
its legs outwards. It doesn't seem any surprise to me at all that this
is very hit and miss, and that mine just slid straight back out of the
same hole they went in. Holes were drilled 12mm as specified, into red
brick, with placement such that anchors were in the middle of bricks in
all three planes. Am I doing something wrong?

Anyway, to rectify matters... I need to reinstate the two missing bolts,
preferably without removing the joist again, and have been searching the
archives for resin anchoring methods which I've never seen or used. Am
I right in thinking that this is an appropriate application for this?
Could I just fill the holes (ie through the joist) with resin and then
just ram a length of M10? M12? threaded bar straight down? Would
certainly solve a lot of grief!

Thanks
David

Lobster wrote:
I right in thinking that this is an appropriate application for this?


I'd think so, though I'm talking from the limited experience of having
researched and used these on one job. I posted the details to another
thread on the subject.

Could I just fill the holes (ie through the joist) with resin and
then
just ram a length of M10? M12? threaded bar straight down?

I filled through the PFC channel I was fitting so I can't see any
problems there, the applicator spout was very long and could easily
have coped with another 100mm. Get the hole as clean as you can, brush
and blow a few times. The system I used specified a 75mm deep M10 hole
for M8 studs, so use studs 2mm smaller than the holes you have.

If the bricks are hollow then you may have problems, I think you need a
liner of some sort for those cases.

The ones in the URL adon't look like they were intended for a blind
hole fixing (ie/ one sided) - they look like they were intended to be
inserted right through the workpiece from the non-fixing side....

For blind fixings, a washer goes behind the joist, and with the nut on
the outside this means the bolt 'head' in the blind hole has to expand
as the nut is tightened.

Phil wrote:
The ones in the URL adon't look like they were intended for a blind
hole fixing (ie/ one sided) - they look like they were intended to be
inserted right through the workpiece from the non-fixing side....

well, that would explain my lack of success suppose, and I did wonder
about that; but why would a fancy fitting like this be needed if you had
access on both sides? Surely an ordinary bolt, washer and nut would
suffice and do the job much better?

For blind fixings, a washer goes behind the joist, and with the nut on
the outside this means the bolt 'head' in the blind hole has to expand
as the nut is tightened.

If I understand you rightly, wouldn't that make the anchors open up
extremely close to the surface of the brick I'm attaching to (especially
as it's plastered! although I suppose that could and maybe should have
been removed), and very likely to burst out?

Thanks
David

In article ,
Lobster wrote:
I've been using M12 thrubolt anchors like these...
http://tinyurl.com/4lkgu
... to attach a joist parallel to the wall, but they haven't 'worked' at
all well, in that one just pulled out of the wall when I tightened the
bolt; and when I removed the joist to try to rectify this, another one
failed as well when I replaced the bolt and retightened it. (The
remaining two are well anchored and work fine).

Think I'd stick to the normal 'Rawlbolt' type. Those can't pull out while
tightening as they sort of pull against themselves.

--
*42.7% of statistics are made up. Sorry, that should read 47.2% *

Dave Plowman London SW
To e-mail, change noise into sound.

I used some (outwardly identical versions) of these bolts in a very
similar situation - attaching the header board of a deck to a brick
wall. The thing seemed to be that the anchor was a very tight fit in
the hole to start with - they had to be driven in with a hammer. The
protrusions then bind in the hole, and the whole thing locks solid when
it's tightened. I'm guessing that if the hole was a little large to
start with the process might not bootstrap properly and all that would
happen is the device would gradually pull out.

Does it sound like this might be what happened?

regards,

Mark

Phil wrote:
The ones in the URL adon't look like they were intended for a blind
hole fixing (ie/ one sided) - they look like they were intended to be
inserted right through the workpiece from the non-fixing side....

For blind fixings, a washer goes behind the joist, and with the nut
on
the outside this means the bolt 'head' in the blind hole has to
expand
as the nut is tightened.

Lobster wrote:

I've been using M12 thrubolt anchors like these...
http://tinyurl.com/4lkgu
... to attach a joist parallel to the wall, but they haven't 'worked' at
all well, in that one just pulled out of the wall when I tightened the
bolt; and when I removed the joist to try to rectify this, another one
failed as well when I replaced the bolt and retightened it. (The
remaining two are well anchored and work fine).

You should drill a hole of the correct depth and diameter (same as the
bolt) and hammer these in, then do up the nut. I've never used these in
brick, only concrete - are they supposed to be suitable for brickwork?
The hole diameter needs to be accurate. Perhaps loose rawl bolts would
be better? What are you actually fixing?

The washer 'stops' against a shoulder at the end of the thread. The
sleeve then transfers this foce down the hole to the 'speady outy bit'
at the end....

The hammer in versions have a length of unthreaded bolt on the end of
the thread to hit them in with....

wrote:
I used some (outwardly identical versions) of these bolts in a very
similar situation - attaching the header board of a deck to a brick
wall. The thing seemed to be that the anchor was a very tight fit in
the hole to start with - they had to be driven in with a hammer. The
protrusions then bind in the hole, and the whole thing locks solid when
it's tightened. I'm guessing that if the hole was a little large to
start with the process might not bootstrap properly and all that would
happen is the device would gradually pull out.

Thanks for all the replies.

Does it sound like this might be what happened?

Yes, sure. Mine certainly weren't that tight; I had to tap them in with
a hammer but it didn't take much effort. Soft brick? Too-heavy Ferm
SDS drill wobbling in the hole? The thread on the fittings is M12, and
the pack specified a 12 mm hole, which is what I drilled in the brick
(would that be expected to yield a very tight fit?)

David

Dave Plowman (News) wrote:
In article ,
Lobster wrote:

I've been using M12 thrubolt anchors like these...
http://tinyurl.com/4lkgu
... to attach a joist parallel to the wall, but they haven't 'worked' at
all well, in that one just pulled out of the wall when I tightened the
bolt; and when I removed the joist to try to rectify this, another one
failed as well when I replaced the bolt and retightened it. (The
remaining two are well anchored and work fine).


Think I'd stick to the normal 'Rawlbolt' type. Those can't pull out while
tightening as they sort of pull against themselves.

Mm. will do next time!

Can anybody else (ie as well as urchaidh!) confirm that my 'resin' plan
is a good way forward now?

David

Lobster wrote:
Dave Plowman (News) wrote:
In article ,

I've been using M12 thrubolt anchors like these...
http://tinyurl.com/4lkgu
... to attach a joist parallel to the wall, but they haven't
'worked' at
all well, in that one just pulled out of the wall when I tightened
the
bolt; and when I removed the joist to try to rectify this, another
one
failed as well when I replaced the bolt and retightened it. (The
remaining two are well anchored and work fine).


Think I'd stick to the normal 'Rawlbolt' type. Those can't pull out
while
tightening as they sort of pull against themselves.

Mm. will do next time!

Can anybody else (ie as well as urchaidh!) confirm that my 'resin'
plan
is a good way forward now?

David

Resin is the best, used kilos of the stuff and it gives A1 fixing
performance. If you use the non-epoxy types, move fast, as it sets very
quickly indeed. Inject resin, stick threaded rod in, let set. Much
superior to expansion fixings.


NT

In article
glegroups.com,
wrote:
Resin is the best, used kilos of the stuff and it gives A1 fixing
performance. If you use the non-epoxy types, move fast, as it sets very
quickly indeed. Inject resin, stick threaded rod in, let set. Much
superior to expansion fixings.

In what way? Cheaper?

I've used loads of rawlbolt type fittings around the house and never had
one fail. Dunno about fixing into lightweight blocks, though.

--
*Consciousness: That annoying time between naps.

Dave Plowman London SW
To e-mail, change noise into sound.

Lobster wrote:
Dave Plowman (News) wrote:

In article ,
Lobster wrote:

I've been using M12 thrubolt anchors like these...
http://tinyurl.com/4lkgu
... to attach a joist parallel to the wall, but they haven't 'worked'
at all well, in that one just pulled out of the wall when I tightened
the bolt; and when I removed the joist to try to rectify this,
another one failed as well when I replaced the bolt and retightened
it. (The remaining two are well anchored and work fine).



Think I'd stick to the normal 'Rawlbolt' type. Those can't pull out while
tightening as they sort of pull against themselves.


Mm. will do next time!

Can anybody else (ie as well as urchaidh!) confirm that my 'resin' plan
is a good way forward now?

David

WTF are these posts prefaced "REPOST"? Where have they come from? I
certainly haven't reposted my query...

David

Dave Plowman (News) wrote:
In article
glegroups.com,
wrote:
Resin is the best, used kilos of the stuff and it gives A1 fixing
performance. If you use the non-epoxy types, move fast, as it sets
very
quickly indeed. Inject resin, stick threaded rod in, let set. Much
superior to expansion fixings.

In what way? Cheaper?

they bond better to the brick, as theyre bonding to every square mill
in the hole, not just some of the area. Also they put no forces on the
brick, so dont tend to break it, which expansion fixings sometimes do.
Also they bond the material round the hole togther, which again
expansion fixings dont. Theyre especially recommended for near-edge
fixings, where expansion fixers would simply break the material.


NT

In article , "Lobster"
says...
snip

WTF are these posts prefaced "REPOST"? Where have they come from? I
certainly haven't reposted my query...

If you look at the header you will see

Sender:
X-Reposted-By:
X-Comments: This article is being re-posted. It was canceled
X-Comments: in error. For more information, please contact:
X-Comments: .

Rob Morley wrote:
In article , "Lobster"
says...
snip

WTF are these posts prefaced "REPOST"? Where have they come from? I
certainly haven't reposted my query...


If you look at the header you will see

Sender:
X-Reposted-By:
X-Comments: This article is being re-posted. It was canceled
X-Comments: in error. For more information, please contact:
X-Comments: .

Does this mean what I think it does: that one particular newsfeed has
accidentally cancelled some posts on its system, so has decided to
rebroadcast them to the entire internet? Why would it do that? Just
curious...

David