sleeve/shield anchors

[Robert]

Hello,

Screwfix sell some sleeve anchors and some shield anchors. They look very similar to me. Is there a difference between them?

SF also sell expansion plugs, which look like a sleeve anchor without the nut. Is that what they are? Can you use any bolt in them or is there a rule about the maximum length? I see that the anchors state the maximum width of the fitting that can be secured.

There are also thru bolts which look like a similar thing. All these different fixings. Is there a web site that explains them all? My head aches!

[Jón Fairbairn]

Sleeve anchors are (I think) a metal tube that is bent open by a cone being pulled in when the screw is tightened. I think that's a one-off process, so you can't really re-use them.

Shield anchors have separate parts that are pushed apart by the cone, which means that if you loosen the screw you can wiggle them out and re-use them.

Without the screw, certainly -- they look like sleeve anchors, ie metal that bends.

I'm not sure which type of expansion these have, but I think these do have nuts on a threaded stud that pulls the cone, rather than screws going into an expanding nut.

[Andy Dingley]

Generally they difference is that a shield anchor is the classic Rawlbolt, with a number of rigid, hinged shields. Sleeve anchors use a flexible tube instead. Both are expanded when an internal wedge is tightened.

The difference is mostly one of size - big ones are shields, small ones are sleeves. Where there's an overlap in the middle, a shield works well when a strong, rigid wall can accept the load from a small number of contact points. A sleeve gives a more conformal fit, so doesn't overload the wall at points - shields are more likely to give problems with cracking or crumbling their support point.

You can also remove shields by unbolting with fairly good success, but not sleeves.

[The Medway Handyman]

Wot John said was absolutely spot on, but its worth mentioning the multi monti

thunderbolt multi monti blurb reads;

Versatile alternative to the traditional shield anchor. Fast and easy to use, it's very popular in Europe. Great in cracked and uncracked concrete, F120 fire protection concrete, sand lime brick and solid brick. Its no expansion effect makes tight spacing close to the edge possible! High Quality Carbon Steel No Plugs Required Easy Driving - No Special Application Tools Required Suitable for Light, Medium & Heavy Loads Specially Designed Cutting Teeth Reduce Required Driving Force Reusable & Long Lasting for Exterior Applications

Basically you drill a hole (smaller than for a sleeve/shield anchor) & drive them in with a drill or impact driver.

Much faster to install, incredibly strong fix.

The SF ones are in larger packs (50 or 100) but available in more styles e.g. CS, Torx & hex. The TS ones are only hex head, but you can buy packs of 10.

[Robert]

I was meaning to thank John for his post, sorry I haven't done so sooner.

...

They sound very interesting. I like that they are removable. I have just discovered that a set of shelves was held up by some thrubolts and now I had got the headache of removing them (another thread).

These sound like a good idea. Is there a minimum distance that they have to fit into the wall and is there a maximum thickness of fixing that they will hold?

What I don't understand is how can they be repeatedly inserted and removed from the same hole? Doesn't the concrete/brick eventually get worn away, making the hole bigger?

Thank you Rob