My dear old Mum has a pair of 1.8m? oak, 5-bar gates at the entrance to her drive. The 100mm (wide) x 75mm (deep) posts are fixed to brick piers with some kind of expanding bolt, one of which has become loose in the brickwork, I suspect it has rusted (she's just 300 metres from the sea and even plastic rusts down there!) I want to add a further fixing to secure the post without the bother of removing the gate and the existing fixing. Q1. Should I use a sleeve anchor bolt or a concrete bolt (Thunderbolt)? Q2. If I recess the bolt head into the 75mm post, what length of bolt needs to be in the brick for a secure fixing? (I'll do my best to avoid the frog!)
Summink like this maybe http://www.screwfix.com/p/multi-fix-silver-multi-fix-masonry-bolts-12-x-150mm-pack-of-10/50323
That looks like a good call from Para. I haven't used these types of bolts myself, but the reviews are all good (and one is about fixing a timber gate post to a brick pillar like you). I'll certainly use them next time for similar jobs. I think I'd recommend using them with washers, although this will also mean the countersink hole you'll need to drill for the head will now have to be large enough to take the washer. From experience, it can be a 'mare when the nut's head starts to sink into the bottom of the timber hole, and the socket can't grip any more. Washers are also cheap - from our hosts. Since they are so potentially easy to fit, I'd be inclined to fit more than one, to be sure to be sure. I presume you have an SDS drill?
Thunderbolts are brilliant, you can you them closer to the edge of materials without the risk of busting out.
Thanks D.A. I haven't used concrete bolts before either, hence my reason for seeking advice here. I've got plenty of washers and the right size go-faster flat bit and an SDS drill. I was just wondering whether the concrete bolt would withstand the forces of the gate being slammed, together with it's fairly impressive weight. I too have suffered the sinking nut's head - luckily I had the right sized box spanner to take over when the socket wouldn't reach.
Thunderbolts & gate post thread from last year. http://community.screwfix.com/threads/fixing-fence-post-to-a-wall-for-gate-support.150121/
Ah, so 2mm smaller hole than the quoted bolt size. That's useful to know. Thanks. Now I've just read somewhere else that the quoted size is for the bolt shank and the thread is another 2mm!! I think I'll test drill an old brick to be sure before I make a faux pas!
Thanks Kiab. I had read that thread before I posted but just wanted a second opinion re sleeve anchors vs concrete bolts for my particular application. I'm getting the feeling that concrete bolts are the way to go.
Has the timber post moved away enough from the brick pillar to leave a gap? If so, I'd be inclined to inject some good adhesive (StixAll or similar) in there before tightening up. This isn't so much to actually stick the post to the pillar, but to prevent any movement betwixt them. It's the tiny movements from use that can begin to loosen almost any type of fixing.
Trust me,once you have used Thunderbolts, or whatever name they are using now, you won't go back to anything else. I have fixed engineering machine tools down with them. No problems whatsoever.
Thanks malkie. Being old school and used to rawbolts & rawlplugs, I was hesitant to trust these new-fangled 'screw straight into substrate' bolts but from opinions received, it appears that I need not be concerned about their efficacy.
I was very sceptical about these when Mr Chippie pointed them out to me. I'm happy to say that they defy the laws of classical mechanics magnificently though.
Maybe I can understand the confusion.... Screwfix describe "Multi-Fix Silver Multi-Fix Masonry Bolts 12 x 150mm Pack of 10 Product Code: 50323" but the manufacturer's label reads 10 x 150. Thankfully it also states "Drill Hole Dia. 10mm" & "Clearance Hole in Fixture: 12mm".